Rationale: Human rhinoviruses (HRV) are the leading cause of upper respiratory infections and have been postulated to trigger asthma exacerbations. However, whether HRV are detected during crises because upper respiratory infections often accompany asthma attacks, or because they specifically elicit exacerbations, is unclear. Moreover, although several hypotheses have been advanced to explain virus-induced exacerbations, their mechanism remains unclear.
Objectives: To determine the role of HRV in pediatric asthma exacerbations and the mechanisms mediating wheezing.
Methods: We prospectively studied 409 children with asthma presenting with upper respiratory infection in the presence or absence of wheezing. Candidate viral and immune mediators of illness were compared among children with asthma with different degrees of severity of acute asthma.
Measurements and Main Results: HRV infections specifically associated with asthma exacerbations, even after adjusting for relevant demographic and clinical variables defined a priori (odds ratio, 1.90; 95% confidence interval, 1.21–2.99; P = 0.005). No difference in virus titers, HRV species, and inflammatory or allergic molecules was observed between wheezing and nonwheezing children infected with HRV. Type III IFN-λ1 levels were higher in wheezing children infected with HRV compared with nonwheezing (P < 0.001) and increased with worsening symptoms (P < 0.001). Moreover, after adjusting for IFN-λ1, children with asthma infected with HRV were no longer more likely to wheeze than those who were HRV-negative (odds ratio, 1.18; 95% confidence interval, 0.57–2.46; P = 0.66).
Conclusions: Our findings suggest that HRV infections in children with asthma are specifically associated with acute wheezing, and that type III IFN-λ1 responses mediate exacerbations caused by HRV. Modulation of IFN- λ1 should be studied as a therapeutic target for exacerbations caused by HRV.
asthma; interferon-λ; rhinovirus; children; asthma exacerbation
Optimal timing of antiretroviral therapy in HIV-infected persons is unclear, although two recent large observational studies have improved our understanding of the best CD4 threshold for initiation. These studies compared the effect of starting HAART on mortality and mortality/AIDS between strata defined using broad ranges of CD4 counts. We sought to expand this understanding using a novel statistical approach proposed by Robins and colleagues.
Using observational data from 1034 antiretroviral-naïve HIV-infected patients from Nashville, Tennessee, we directly estimated the optimal CD4 count for initiation of HAART to maximize patient health 6, 12, 24, and 36 months after the first instance of CD4 falling below 750. We measured health using two outcome metrics, one based on CD4 counts at the end of follow-up and the other based on a published quality-of-life scale; both metrics incorporated death, AIDS-defining events, serious non-AIDS events, and CD4 at the end of follow-up if asymptomatic.
The CD4-based metric estimated that to maximize health 6, 12, 24, and 36 months after study entry, HAART should be initiated within 3 months of CD4 first dropping below 495 (95% confidence interval [CI] = 468 – 522), 554 (459 – 750), 489 (427 – 750), and 509 (460 – 750), respectively. The quality-of-life-based metric produced CD4 initiation threshold estimates of 337 (95% CI = 201–442), 354 (288 – 386), 358 (294 – 750), and 475 (287 – 750) for the same time points.
Our results support early initiation of antiretroviral therapy, although the criterion for starting therapy depends on the choice of health outcome.
To assess incidence, burden of illness, and risk factors for human rhinoviruses (HRVs) in a cohort of very low birth weight (VLBW) infants.
A 2-year prospective cohort study was conducted among VLBW premature infants in Buenos Aires, Argentina. Infants were enrolled in the NICU from June 1, 2003, to May 31, 2005, and managed monthly and with every acute respiratory illness (ARI) during the first year of life. Nasal wash samples were obtained during every respiratory episode and tested for HRV, respiratory syncytial virus (RSV), human parainfluenza viruses, influenza viruses, and human metapneumovirus using reverse transcriptase-polymerase chain reaction.
Of 119 patients, 66 (55%) had HRV-associated ARIs. The incidence of HRV-associated ARI was 123 events per 100 child-years of follow-up. Of those infants experiencing an episode of bronchiolitis, 40% had HRV versus 7% with RSV. The incidence of HRV-associated bronchiolitis was 75 per 100 infant-years of follow-up. HRV was associated with 12 of 36 hospitalizations (33%), and RSV was associated with 9 of 36 hospitalizations (25%). The incidence of HRV-associated hospitalization was 12 per 100 infant-years of follow-up. The risk of HRV-associated hospitalization was higher for infants with bronchopulmonary dysplasia and those who were not breastfed.
HRV is an important and frequent pathogen associated with severe respiratory infections in VLBW infants. Bronchopulmonary dysplasia and the absence of breastfeeding are risk factors for hospitalization. The results of our study reveal that HRV is the predominant pathogen of respiratory infections in premature infants.
premature infants; rhinovirus; very low birth weight
Sarcoidosis is a non-caseating granulomatous disease for which a role for infectious antigens continues to strengthen. Recent studies have reported molecular evidence of mycobacteria or propionibacteria. We assessed for immune responses against mycobacterial and propionibacterial antigens in sarcoidosis bronchoalveolar lavage (BAL) using flow cytometry, and localized signals consistent with microbial antigens with sarcoidosis specimens, using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS).
BAL cells from 27 sarcoidosis, 14 PPD- controls, and 9 subjects with nontuberculosis mycobacterial (NTM) infections were analyzed for production of IFN-γ after stimulation with mycobacterial ESAT-6 and Propionibacterium acnes proteins. To complement the immunological data, MALDI-IMS was performed to localize ESAT-6 and Propionibacterium acnes signals within sarcoidosis and control specimens.
CD4+ immunologic analysis for mycobacteria was positive in 17/27 sarcoidosis subjects, compared to 2/14 PPD-subjects, and 5/9 NTM subjects (p=00.008 and p=00.71 respectively, Fisher's exact test). There was no significant difference for recognition of P. acnes, which occurred only in sarcoidosis subjects that also recognized ESAT-6. Similar results were also observed for the CD8+ immunologic analysis. MALDI-IMS localized signals consistent with ESAT-6 only within sites of granulomatous inflammation, whereas P. acnes signals were distributed throughout the specimen.
MALDI-IMS localizes signals consistent with ESAT-6 to sarcoidosis granulomas, whereas no specific localization of P. acnes signals is detected. Immune responses against both mycobacterial and P. acnes are present within sarcoidosis BAL, but only mycobacterial signals are distinct from disease controls. These immunologic and molecular investigations support further investigation of the microbial community within sarcoidosis granulomas.
Sarcoidosis; mycobacteria; propionibacteria; bronchoalveolar lavage; mass spectrometry; MALDI-IMS
Human immunodeficiency virus (HIV)-infected women in India and other developing country settings are living longer on antiretroviral therapy, yet their risk for human papillomavirus (HPV)-induced cervical cancer remains unabated because of lack of cost-effective and accurate secondary prevention methods. Visual inspection after application of dilute acetic acid on the cervix (VIA) has not been adequately studied against the current standard: conventional cervical cytology (Pap smears) among HIV-infected women. We evaluated 303 nonpregnant HIV-infected women in Pune, India, by simultaneous and independent screening with VIA and cervical cytology with disease ascertainment by colposcopy and histopathology. At the cervical intraepithelial neoplasia (CIN2+) disease threshold, the sensitivity, specificity and positive and negative predictive value estimates of VIA were 80, 82.6, 47.6 and 95.4% respectively, compared to 60.5, 59.6, 22.4 and 88.7% for the atypical squamous cells of undetermined significance or severe (ASCUS+) cutoff on cytology, 60.5, 64.6, 24.8 and 89.4% for the low-grade squamous intraepithelial cells or severe (LSIL+) cutoff on cytology and 20.9, 96.0, 50.0 and 86.3% for high-grade squamous intraepithelial lesion or severe (HSIL+) cutoff on cytology. A similar pattern of results was found for women with the presence of carcinogenic HPV-positive CIN2+ disease, as well as for women with CD4+ cell counts <200 and <350 µL−1. Overall, VIA performed better than cytology in this study with biologically rigorous endpoints and without verification bias, suggesting that VIA is a practical and useful alternative or adjunctive screening test for HIV-infected women. Implementing VIA-based screening within HIV/acquired immunodeficiency syndrome care programs may provide an easy and practical means of complementing the highly anticipated low-cost HPV-based rapid screening tests in the near future, thereby contributing to improve program effectiveness of screening.
cervical cancer; visual inspection; cytology; screening; HIV/AIDS; India
In a cohort of human immunodeficiency virus–infected adults beginning antiretroviral therapy, CD4+ lymphocyte recovery at 12 months was highest among overweight patients (body mass index, 25–30 kg/m2). Similar results were observed in the subgroups with virologic suppression and minimal weight change.
Background. Higher body mass index (BMI) was associated with slower human immunodeficiency virus (HIV) disease progression before the availability of effective antiretroviral therapy (ART), but the relationship between pretreatment BMI and CD4+ lymphocyte recovery on ART is not well described.
Methods. We conducted an observational cohort study of HIV-infected, ART-naive adults starting treatment at a clinic affiliated with Vanderbilt University in Nashville, Tennessee. We assessed the relationship between pretreatment BMI and CD4+ lymphocyte count change from baseline to 12 months in all subjects, among those with plasma HIV-1 RNA levels <400 copies/mL for ≥6 months and those with <10% change in weight during follow-up. Linear regression models were adjusted for age, sex, race, protease inhibitor usage, year of ART initiation, and baseline CD4+ lymphocyte count and HIV-1 RNA level.
Results. A total of 915 patients met inclusion criteria; 78% were male, and their median age, BMI, and CD4+ lymphocyte count were 39 years, 24 kg/m2, and 171 cells/μL, respectively. The CD4+ lymphocyte increase at 12 months was greatest among patients with a pretreatment BMI of ∼25–30 kg/m2 and diminished above and below this range (P = .03). Similar patterns were observed in the subgroup analyses. Among patients with a pretreatment CD4+ lymphocyte count <200 cells/μL, a BMI of ∼25 kg/m2 was associated with the highest odds of reaching a CD4+ lymphocyte count >350 cells/μL at 12 months (P = .05).
Conclusions. 12-month immune reconstitution on ART was highest among patients commonly classified as overweight, suggesting there may be an optimal BMI range for immune recovery on ART.
Some retrospective studies have found that HIV-infected women have a higher mortality risk than men after adjusting for baseline characteristics, while others have not. Anemia is a known predictor of HIV-related mortality. We assessed whether anemia contributed to the sex difference in mortality in our cohort.
We conducted a retrospective cohort study among HIV-infected persons in care at the Comprehensive Care Center (Nashville, TN) between 1998 and 2009. Cox proportional hazards models compared time from first clinic visit to death and AIDS-defining events (ADE), adjusted for baseline characteristics with and without baseline hemoglobin.
Of 3,633 persons, 879 (24%) were women. Women had lower median baseline hemoglobin compared to men: 12.4 g/dL (inter-quartile range (IQR) 11.3–13.4) vs. 14.4 (IQR 13.1–15.5), respectively (P<0.001). In multivariable models without hemoglobin, the risk of death was higher among women: hazard ratio (HR) 1.46 (95% confidence interval (CI) 1.17, 1.82; P = 0.001). In multivariable models with hemoglobin, the risk of death in women was diminished and no longer statistically significant: HR 1.2 (95% CI 0.93, 1.55; P = 0.17). The risk of ADE was higher among women in both models, but not statistically significant: HR 1.1 (95% CI 0.85–1.42; P = 0.46) in the model without hemoglobin and 1.11 (95% CI 0.82–1.48; P = 0.50) in the model with hemoglobin. Hemoglobin was a strong predictor of death: HR 0.88 per 1 g/dL increase (95% CI 0.83, 0.93; P<0.001).
In our study population of HIV-infected persons in care, women had lower baseline hemoglobin, and lower hemoglobin contributed to their higher risk of ADE and death.
A data coordinating team performed on-site audits and discovered discrepancies between the data sent to the coordinating center and that recorded at sites. We present statistical methods for incorporating audit results into analyses. This can be thought of as a measurement error problem, where the distribution of errors is a mixture with a point mass at 0. If the error rate is non-zero, then even if the mean of the discrepancy between the reported and correct values of a predictor is 0, naive estimates of the association between two continuous variables will be biased. We consider scenarios where there are 1) errors in the predictor, 2) errors in the outcome, and 3) possibly correlated errors in the predictor and outcome. We show how to incorporate the error rate and magnitude, estimated from a random subset (the audited records), to compute unbiased estimates of association and proper confidence intervals. We then extend these results to multiple linear regression where multiple covariates may be incorrect in the database and the rate and magnitude of the errors may depend on study site. We study the finite sample properties of our estimators using simulations, discuss some practical considerations, and illustrate our methods with data from 2815 HIV-infected patients in Latin America, of whom 234 had their data audited using a sequential auditing plan.
Data quality; HIV/AIDS; Measurement error
In randomized studies researchers may be interested in the effect of treatment assignment on a time-to-event outcome that only exists in a subset selected after randomization. For example, in preventative HIV vaccine trials, it is of interest to determine whether randomization to vaccine affects the time from infection diagnosis until initiation of antiretroviral therapy. Earlier work assessed the effect of treatment on outcome among the principal stratum of individuals who would have been selected regardless of treatment assignment. These studies assumed monotonicity, that one of the principal strata was empty (eg, every person infected in the vaccine arm would have been infected if randomized to placebo). Here we present a sensitivity analysis approach for relaxing monotonicity with a time-to-event outcome. We also consider scenarios where selection is unknown for some subjects because of non-informative censoring (e.g., infection status k years after randomization is unknown for some because of staggered study entry). We illustrate our method using data from an HIV vaccine trial.
Causal inference; HIV; Kaplan-Meier; Monotonicity; Principal stratification
Injection drug use is associated with poor HIV outcomes even among persons receiving highly active antiretroviral therapy (HAART), but there are limited data on the relationship between non-injection drug use and HIV disease progression.
We conducted an observational study of HIV-infected persons entering care between January 1, 1999 and December 31, 2004, with follow-up through December 31, 2005.
There were 1,712 persons in the study cohort: 262 with a history of injection drug use (IDU), 785 with a history of non-injection drug use, and 665 with no history of drug use; 56% were white, and 24% were females. Median follow-up was 2.1 years, 33% had HAART prior to first visit, 40% initiated first HAART during the study period, and 306 (17.9%) had an AIDS-defining event or died. Adjusting for sex, age, race, prior antiretroviral use, CD4 cell count, and HIV-1 RNA, patients with a history of injection drug use were more likely to advance to AIDS or death than non-users (adjusted hazard ratio (HR) = 1.97, 95% confidence interval (CI) 1.43-2.70, P<0.01). There was no statistically significant difference of disease progression between non-injection drug users and non-users (HR=1.19, 95% CI 0.92-1.56, P=0.19). An analysis among the subgroup who initiated their first HAART during the study period (n=687) showed a similar pattern (IDUs: 1.83, 1.09-3.06, P=0.02; non-IDUs: 1.21, 0.81-1.80, P=0.35). Seventy-four patients had active IDU during the study period, 768 active non-IDU, and 870 no substance use. Analyses based on active drug use during the study period did not substantially differ from those based on history of drug use.
This study shows no relationship between non-injection drug use and HIV disease progression. This study is limited by using history drug use and lumping together different types of drugs. Further studies ascertaining specific type and extent of non-injection drug use in a prospective way, and with longer follow-up, are needed.
Injection drug use; non-injection drug use; CD4 cell count; HIV viral load; HIV disease progression; antiretroviral therapy
HIV infected individuals have heightened cancer risk. With the advent of HAART, the frequency of some AIDS defining cancers (ADC) has decreased while certain non-AIDS defining cancers (NADC) are becoming more frequent. Cancers among HIV-infected individuals in Latin American and the Caribbean have not yet been carefully studied.
Cancer cases among the Caribbean, Central and South American network for HIV Research (CCASAnet) cohort were identified reviewing clinical records and preexisting databases.
There were 406 cancers reported: 331 ADC (224 Kaposi´s sarcomas and 98 non Hodgkin lymphomas). Most frequent NADC (n=75) were Hodgkin lymphoma and skin cancers. Seventy-three percent of NADC and 45% of ADC were diagnosed >1 year after HIV diagnosis. 56% of ADC occurred before HAART start. Median time from HAART start until cancer diagnosis was 2.5 years for NADC and 0.5 years for ADC (p=<0.001). Within 3372 HAART starters, 158 were diagnosed with 165 cancers (82.4% ADC); 85 cases were previous to or concomitant with HAART initiation. Incidence of cancer after HAART initiation in 8080 person-years of follow-up was 7.2 per 1000 person-years (95%CI= 5.5–9.3) for ADC and 2.7 (95%CI= 1.8–4.1) for NADC; incidence was higher in the first two months, particularly for ADC (47.6). A pre-HAART ADC was a predictor of mortality after adjusting for age, sex, and CD4 at HAART initiation.
ADC were the most frequent cancers in this region and were often diagnosed close to HIV diagnosis and HAART start. Incidence of cancer was highest around HAART initiation.
Neoplasms; HIV; Latin America; Caribbean; Cohort Studies
Observational studies of health conditions and outcomes often combine clinical care data from many sites without explicitly assessing the accuracy and completeness of these data. In order to improve the quality of data in an international multi-site observational cohort of HIV-infected patients, the authors conducted on-site, Good Clinical Practice-based audits of the clinical care datasets submitted by participating HIV clinics. Discrepancies between data submitted for research and data in the clinical records were categorized using the audit codes published by the European Organization for the Research and Treatment of Cancer. Five of seven sites had error rates >10% in key study variables, notably laboratory data, weight measurements, and antiretroviral medications. All sites had significant discrepancies in medication start and stop dates. Clinical care data, particularly antiretroviral regimens and associated dates, are prone to substantial error. Verifying data against source documents through audits will improve the quality of databases and research and can be a technique for retraining staff responsible for clinical data collection. The authors recommend that all participants in observational cohorts use data audits to assess and improve the quality of data and to guide future data collection and abstraction efforts at the point of care.
To examine the association between douching and four sexually transmitted infections (STIs).
We followed 411 high-risk HIV-infected and uninfected female adolescents ages 12–19 over a median three-year period, both by time from study entry/first STI-free visit until an incident STI for participants who never, intermittently, and always douched, and also by reported douching at a given STI-free visit and incidence of STI at the next visit, using adjusted Cox proportional hazards models to calculate hazards ratios (HR).
The time to STI was shorter for adolescents who always (HR=2.1; 95% CI, 1.2–3.4) and intermittently (HR=1.5; 95% CI:1.0–2.2) douched compared to never-douchers. An adjusted hazard for STI was 1.8 times larger for always-douchers (95%CI:1.1–3.1) and 1.4 times larger for intermittent-douchers (95%CI:0.9–2.0) compared to never-douchers. When classifying by follow-up post an STI-free visit, always-douchers had a shorter STI-free time than never-douchers (HRadj=2.1; 95%CI:1.5–3.1).
Counseling to discourage douching may reduce STI risk in adolescents.
To compare incidence and distribution of non-AIDS-defining events (NADEs) among HIV-1-infected adults receiving combination antiretroviral therapy (cART) in urban sub-Saharan African versus United States settings.
Retrospective cohort analysis of clinical trial and observational data.
Compared crude and standardized (to US cohort by age and sex) NADE rates from two urban adult HIV-infected cART-initiating populations: a clinical trial cohort in Gaborone, Botswana (Botswana) and an observational cohort in Nashville, Tennessee (USA).
Crude NADE incidence rates were similar: 10.0 [95% confidence interval 6.3–15.9] per 1000 person-years in Botswana versus 12.4 [8.4–18.4] per 1000 person-years in the United States. However, after standardizing to an older, predominantly male US population, the overall NADE incidence rates were higher in Botswana [18.7 (8.3–33.1) per 1000 person-years]. Standardized rates differed most for cardiovascular events (8.4 versus 5.0 per 1000 person-years) and non-AIDS-defining malignancies (8.0 versus 0.5 per 1000 person-years) – both higher in Botswana. Conversely, hepatic NADE rates were higher in the United States (4.0 versus 0.0 per 1000 person-years), whereas renal NADE rates [3.0 per 1000 person-years (United States) versus 2.4 per 1000 person-years (Botswana)] were comparable.
Crude NADE incidence rates were similar between cART-treated patients in a US observational cohort and a sub-Saharan African clinical trial. However, when standardized to the US cohort, overall NADE rates were higher in Botswana. NADEs appear to be a significant problem in our sub-Saharan African setting, and the monitoring, prevention, and treatment of NADEs should be a critical component of care in resource-limited settings.
combination antiretroviral therapy; HIV/AIDS; non-AIDS-defining events; urban sub-Saharan Africa; urban United States
We evaluated the burden of sexual- or injection drug use (IDU)-related infections in male prisoners in Karachi, Pakistan.
We administered a structured questionnaire in a cross-sectional survey of 365 randomly selected imprisoned men. We analyzed blood for human immunodeficiency virus (HIV) and Hepatitis B and C by ELISA, and for syphilis by rapid plasma reagin and Treponema pallidum hemagglutination assay confirmation. Subjects with possible tuberculosis (WHO criteria) provided sputum samples for an acid fast bacillus smear and culture.
Prevalence of tuberculosis was 2.2% (95%CI: 0.71, 3.8). HIV infected 2.0% (95%CI: 0.55, 3.4) of 357 randomly selected prisoners (8 refused to give blood), with confirmed syphilis in 8.9% (95%CI: 6.0, 11.8), hepatitis B virus in 5.9% (95%CI: 3.5, 8.3), and hepatitis C virus in 15.2% (95%CI: 11.7, 18.8). By self-report, 59.0% had used any illicit drugs, among whom 11.8% (95%CI: 8.5, 15.0) had injected drugs. The median length of stay in the prison had been 3.2 (range 1-72) months.
All four infections were prevalent among the prisoners in Pakistan. Prisons are excellent venues for infectious disease screening and intervention given conditions of poverty and drug addiction. Collaboration with community-based health providers is vital for post-discharge planning.
Infectious disease; substance abuse; prison; epidemiology; Pakistan
Starting HAART in a very advanced stage of disease is assumed to be the most prevalent form of initiation in HIV-infected subjects in developing countries. Data from Latin America and the Caribbean is still lacking. Our main objective was to determine the frequency, risk factors and trends in time for being late HAART initiator (LHI) in this region.
Cross-sectional analysis from 9817 HIV-infected treatment-naïve patients initiating HAART at 6 sites (Argentina, Chile, Haiti, Honduras, Peru and Mexico) from October 1999 to July 2010. LHI had CD4+ count ≤200cells/mm3 prior to HAART. Late testers (LT) were those LHI who initiated HAART within 6 months of HIV diagnosis. Late presenters (LP) initiated after 6 months of diagnosis. Prevalence, risk factors and trends over time were analyzed.
Among subjects starting HAART (n = 9817) who had baseline CD4+ available (n = 8515), 76% were LHI: Argentina (56%[95%CI:52–59]), Chile (80%[95%CI:77–82]), Haiti (76%[95%CI:74–77]), Honduras (91%[95%CI:87–94]), Mexico (79%[95%CI:75–83]), Peru (86%[95%CI:84–88]). The proportion of LHI statistically changed over time (except in Honduras) (p≤0.02; Honduras p = 0.7), with a tendency towards lower rates in recent years. Males had increased risk of LHI in Chile, Haiti, Peru, and in the combined site analyses (CSA). Older patients were more likely LHI in Argentina and Peru (OR 1.21 per +10-year of age, 95%CI:1.02–1.45; OR 1.20, 95%CI:1.02–1.43; respectively), but not in CSA (OR 1.07, 95%CI:0.94–1.21). Higher education was associated with decreased risk for LHI in Chile (OR 0.92 per +1-year of education, 95%CI:0.87–0.98) (similar trends in Mexico, Peru, and CSA). LHI with date of HIV-diagnosis available, 55% were LT and 45% LP.
LHI was highly prevalent in CCASAnet sites, mostly due to LT; the main risk factors associated were being male and older age. Earlier HIV-diagnosis and earlier treatment initiation are needed to maximize benefits from HAART in the region.
This retrospective cohort study of HIV-infected women receiving highly active antiretroviral therapy (HAART) while pregnant assessed the effect of postpartum HAART discontinuation on maternal AIDS-defining events (ADEs), non-AIDS–defining events (non-ADEs), and death 1997–2008 in Nashville, Tennessee. Cox proportional hazards models compared rates of ADE or all-cause death and non-ADE or all-cause death, and competing risks analyses compared rates of ADE or ADE-related death and non-ADE or non-ADE–related death across the groups. There were two groups: women who stopped HAART postpartum (discontinuation, n = 54) and women who continued HAART postpartum (continuation, n = 69). Fifty percent were African American, 40% had prior non-HAART antiretroviral therapy (ART) use, and 38% had a history of illicit drug use. Median age was 27.5 years, baseline CD4(%) was 532 (34%) and CD4 nadir was 332 cells/mm3, baseline and peak HIV-1 RNA were 2.6 and 4.32 log10 copies per milliliter, respectively. Women in the continuation group were older, had lower baseline CD4, CD4%, and CD4 nadir, and had higher peak HIV-1 RNA. In multivariable proportional hazards models, the hazard ratios [95% confidence interval (CI)] of ADE or all-cause death and non-ADE or all-cause death were lower in the continuation group, but not statistically significantly: 0.50 (0.12, 2.12; p = 0.35) and 0.69 (0.24, 1.95; p = 0.48), respectively. The results were similar in competing risks analyses. Despite having characteristics associated with worse prognosis, women who continued HAART postpartum had lower hazard ratio point estimates for ADEs or death and non-ADEs or death than women who discontinued HAART. Larger studies with longer follow-up are indicated to assess this association.
A low body mass index (BMI) at antiretroviral therapy (ART) initiation is a strong predictor of mortality among HIV-infected adults in resource-constrained settings. The relationship between nutrition and inflammation-related serum biomarkers and early treatment outcomes (e.g., less than 90 days) in this population is not well described.
An observational cohort of 142 HIV-infected adults in Lusaka, Zambia, with BMI under 16 kg/m2 or CD4+ lymphocyte counts of less than 50 cells/mm3, or both, was followed prospectively during the first 12 weeks of ART. Baseline and serial post-treatment phosphate, albumin, ferritin and highly sensitive C-reactive protein (hsCRP) serum levels were measured. The primary outcome was mortality.
Lower baseline phosphate and albumin serum levels, and higher ferritin and hsCRP, were significantly associated with mortality prior to 12 weeks (p < 0.05 for all comparisons), independent of known risk factors for early ART-associated mortality in sub-Saharan Africa. The time-dependent interval change in albumin was associated with mortality after adjusting for the baseline value (AHR 0.62 [0.43, 0.89] per 5 g/L increase), but changes in the other biomarkers were not.
The predictive value of serum biomarkers for early mortality in a cohort of adults with malnutrition and advanced HIV in a resource-constrained setting was primarily driven by pre-treatment values, rather than post-ART changes. Interventions to promote earlier HIV diagnosis and treatment, address nutritional deficiencies, and identify the etiologies of increased systemic inflammation may improve ART outcomes in this vulnerable population.
We propose a new set of test statistics to examine the association between two ordinal categorical variables X and Y after adjusting for continuous and/or categorical covariates Z. Our approach first fits multinomial (e.g., proportional odds) models of X and Y, separately, on Z. For each subject, we then compute the conditional distributions of X and Y given Z. If there is no relationship between X and Y after adjusting for Z, then these conditional distributions will be independent, and the observed value of (X, Y) for a subject is expected to follow the product distribution of these conditional distributions. We consider two simple ways of testing the null of conditional independence, both of which treat X and Y equally, in the sense that they do not require specifying an outcome and a predictor variable. The first approach adds these product distributions across all subjects to obtain the expected distribution of (X, Y) under the null and then contrasts it with the observed unconditional distribution of (X, Y). Our second approach computes “residuals” from the two multinomial models and then tests for correlation between these residuals; we define a new individual-level residual for models with ordinal outcomes. We present methods for computing p-values using either the empirical or asymptotic distributions of our test statistics. Through simulations, we demonstrate that our test statistics perform well in terms of power and Type I error rate when compared to proportional odds models which treat X as either a continuous or categorical predictor. We apply our methods to data from a study of visual impairment in children and to a study of cervical abnormalities in human immunodeficiency virus (HIV)-infected women. Supplemental materials for the article are available online.
Categorical data analysis; Concordance–discordance; Regression for ordinal outcome; Residual for ordinal outcome
To evaluate a model for predicting time to AIDS or death among HIV-infected persons initiating highly active antiretroviral therapy (HAART).
Study Design and Setting
The model was constructed from 1,891 HAART initiators in the Collaborations in HIV Outcomes Research/US (CHORUS) cohort. The model's predictive ability was assessed using internal bootstrap validation techniques and data from 716 HAART initiators at Johns Hopkins HIV Clinical Cohort (JHHCC) in whom HIV disease was, in general, more advanced.
The estimated concordance statistic was 0.632 with the bootstrap method and 0.625 in JHHCC. Mean predicted and observed 3-year AIDS-free survival for JHHCC was 0.76 and 0.73 (95% CI 0.69−0.77), respectively; mean predicted and observed 5-year AIDS-free survival was 0.69 and 0.57 (95% CI 0.52−0.62). Sensitivity analyses showed that the discrepancy between predicted and observed AIDS-free survival after 3 years could be due to differences in lost-to-follow-up rates between cohorts.
The model was fair at using baseline characteristics to order patients’ risk of disease progression, but did not accurately predict AIDS-free survival >3 years after HAART initiation. Different variable definitions, patient characteristics, and loss-to-follow-up highlight the challenges of using data from one cohort to predict AIDS-free survival in an independent cohort.
AIDS; Antiretroviral therapy; Bootstrap; CD4 lymphocyte percent; Loss-to-follow-up; Validation; Heterogeneity
In 2003 Thompson and colleagues reported that daily use of finasteride reduced the prevalence of prostate cancer by 25% compared to placebo. These results were based on the double-blind randomized Prostate Cancer Prevention Trial (PCPT) which followed 18,882 men with no prior or current indications of prostate cancer annually for seven years. Enthusiasm for the risk reduction afforded by the chemopreventative agent and adoption of its use in clinical practice, however, was severely dampened by the additional finding in the trial of an increased absolute number of high-grade (Gleason score ≥ 7) cancers on the finasteride arm. The question arose as to whether this finding truly implied that finasteride increased the risk of more severe prostate cancer or was a study artifact due to a series of possible post-randomization selection biases, including differences among treatment arms in patient characteristics of cancer cases, differences in biopsy verification of cancer status due to increased sensitivity of prostate-specific antigen under finasteride, differential grading by biopsy due to prostate volume reduction by finasteride, and nonignorable drop-out. Via a causal inference approach implementing inverse probability weighted estimating equations, this analysis addresses the question of whether finasteride caused more severe prostate cancer by estimating the mean treatment difference in prostate cancer severity between finasteride and placebo for the principal stratum of participants who would have developed prostate cancer regardless of treatment assignment. We perform sensitivity analyses that sequentially adjust for the numerous potential post-randomization biases conjectured in the PCPT.
Causal inference; principal stratification; treatment effects; selection bias
HAART rollout in Latin America and the Caribbean has increased from approximately 210,000 in 2003 to 390,000 patients in 2007, covering 62% (51%–70%) of eligible patients, with considerable variation among countries. No multi-cohort study has examined rates of and reasons for change of initial HAART in this region.
Antiretroviral-naïve patients > = 18 years who started HAART between 1996 and 2007 and had at least one follow-up visit from sites in Argentina, Brazil, Chile, Haiti, Honduras, Mexico and Peru were included. Time from HAART initiation to change (stopping or switching any antiretrovirals) was estimated using Kaplan-Meier techniques. Cox proportional hazards modeled the associations between change and demographics, initial regimen, baseline CD4 count, and clinical stage.
Of 5026 HIV-infected patients, 35% were female, median age at HAART initiation was 37 years (interquartile range [IQR], 31–44), and median CD4 count was 105 cells/uL (IQR, 38–200). Estimated probabilities of changing within 3 months and one year of HAART initiation were 16% (95% confidence interval (CI) 15–17%) and 28% (95% CI 27–29%), respectively. Efavirenz-based regimens and no clinical AIDS at HAART initiation were associated with lower risk of change (hazard ratio (HR) = 1.7 (95% CI 1.1–2.6) and 2.1 (95% CI 1.7–2.5) comparing neverapine-based regimens and other regimens to efavirenz, respectively; HR = 1.3 (95% CI 1.1–1.5) for clinical AIDS at HAART initiation). The primary reason for change among HAART initiators were adverse events (14%), death (5.7%) and failure (1.3%) with specific toxicities varying among sites. After change, most patients remained in first line regimens.
Adverse events were the leading cause for changing initial HAART. Predictors for change due to any reason were AIDS at baseline and the use of a non-efavirenz containing regimen. Differences between participant sites were observed and require further investigation.
Patients starting antiretroviral therapy (ART) for acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa have high rates of mortality in the initial weeks of treatment. We assessed the association of serum phosphate with early mortality among HIV-infected adults with severe malnutrition and/or advanced immunosuppression.
An observational cohort of 142 HIV-infected adults initiating ART in Lusaka, Zambia with body mass index (BMI) <16 kg/m2 or CD4+ lymphocyte count <50 cells/µL, or both, was followed prospectively during the first 12 weeks of ART. Detailed health and dietary intake history, review of systems, physical examination, serum metabolic panel including phosphate, and serum ferritin and high-sensitivity C-reactive protein (hsCRP) were monitored. The primary outcome was mortality. Baseline serum phosphate was a significant predictor of mortality; participants alive at 12 weeks had a median value of 1.30 mmol/L (interquartile range [IQR]: 1.04, 1.43), compared to 1.06 mmol/L (IQR: 0.89, 1.27) among those who died (p<0.01). Each 0.1 mmol/L increase in baseline phosphate was associated with an incremental decrease in mortality (AHR 0.83; 95% CI 0.72 to 0.95). The association was independent of other metabolic parameters and known risk factors for early ART-associated mortality in sub-Saharan Africa. While participant attrition represented a limitation, it was consistent with local program experience.
Low serum phosphate at ART initiation was an independent predictor of early mortality among HIV patients starting ART with severe malnutrition or advanced immunosuppression. This may represent a physiologic phenomenon similar to refeeding syndrome, and may lead to therapeutic interventions that could reduce mortality.
We consider estimation, from a double-blind randomized trial, of treatment effect within levels of base-line covariates on an outcome that is measured after a post-treatment event E has occurred in the subpopulation 𝒫E,E that would experience event E regardless of treatment. Specifically, we consider estimation of the parameters γ indexing models for the outcome mean conditional on treatment and base-line covariates in the subpopulation 𝒫E,E. Such parameters are not identified from randomized trial data but become identified if additionally it is assumed that the subpopulation 𝒫Ē,E of subjects that would experience event E under the second treatment but not under the first is empty and a parametric model for the conditional probability that a subject experiences event E if assigned to the first treatment given that the subject would experience the event if assigned to the second treatment, his or her outcome under the second treatment and his or her pretreatment covariates. We develop a class of estimating equations whose solutions comprise, up to asymptotic equivalence, all consistent and asymptotically normal estimators of γ under these two assumptions. In addition, we derive a locally semiparametric efficient estimator of γ. We apply our methods to estimate the effect on mean viral load of vaccine versus placebo after infection with human immunodeficiency virus (the event E) in a placebo-controlled randomized acquired immune deficiency syndrome vaccine trial.
Counterfactuals; Missing data; Potential outcomes; Principal stratification; Structural model; Vaccine trials
Considerable evidence supports the concept that CD4+ T cells are important in sarcoidosis pathogenesis, but the antigens responsible for the observed Th1 immunophenotype remain elusive. The epidemiologic association with bioaerosols and the presence of granulomatous inflammation support consideration of mycobacterial antigens. To explore the role of mycobacterial antigens in sarcoidosis immunopathogenesis, we assessed the immune recognition of mycobacterial antigens, the 6-kDa early secreted antigenic protein (ESAT-6) and catalase-peroxidase (KatG), by T cells derived from bronchoalveolar lavage (BAL) fluid obtained during diagnostic bronchoscopy. We report the presence of antigen-specific recognition of ESAT-6 and KatG in T cells from BAL fluid of 32/44 sarcoidosis subjects, compared to 1/27 controls (P < 0.0001). CD4+ T cells were primarily responsible for immune recognition (32/44 sarcoidosis subjects), although CD8+ T-cell responses were observed (25/41 sarcoidosis subjects). Recognition was significantly absent from BAL fluid cells of patients with other lung diseases, including infectious granulomatous diseases. Blocking of Toll-like receptor 2 reduced the strength of the observed immune response. The presence of immune responses to mycobacterial antigens in cells from BAL fluid used for sarcoidosis diagnosis suggests a strong association between mycobacteria and sarcoidosis pathogenesis. Inhibition of immune recognition with monoclonal antibody against Toll-like receptor 2 suggests that induction of innate immunity by mycobacteria contributes to the polarized Th1 immune response.