Background. The role of active hepatitis C virus (HCV) replication in chronic kidney disease (CKD) risk has not been clarified.
Methods. We compared CKD incidence in a large cohort of HIV-infected subjects who were HCV seronegative, HCV viremic (detectable HCV RNA), or HCV aviremic (HCV seropositive, undetectable HCV RNA). Stages 3 and 5 CKD were defined according to standard criteria. Progressive CKD was defined as a sustained 25% glomerular filtration rate (GFR) decrease from baseline to a GFR < 60 mL/min/1.73 m2. We used Cox models to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).
Results. A total of 52 602 HCV seronegative, 9508 HCV viremic, and 913 HCV aviremic subjects were included. Compared with HCV seronegative subjects, HCV viremic subjects were at increased risk for stage 3 CKD (adjusted HR 1.36 [95% CI, 1.26, 1.46]), stage 5 CKD (1.95 [1.64, 2.31]), and progressive CKD (1.31 [1.19, 1.44]), while HCV aviremic subjects were also at increased risk for stage 3 CKD (1.19 [0.98, 1.45]), stage 5 CKD (1.69 [1.07, 2.65]), and progressive CKD (1.31 [1.02, 1.68]).
Conclusions. Compared with HIV-infected subjects who were HCV seronegative, both HCV viremic and HCV aviremic individuals were at increased risk for moderate and advanced CKD.
HIV; hepatitis C virus; chronic kidney disease; hepatitis C RNA; cohort study; glomerular filtration rate; injection drug use
Diabetes and hypertension, common conditions in antiretroviral (ART) treated HIV-infected individuals, are associated with glomerular hyperfiltration, which precedes the onset of proteinuria and accelerated kidney function decline. In the Multicenter AIDS Cohort Study, we examined the extent to which hyperfiltration is present and associated with metabolic, cardiovascular, HIV and treatment risk factors among HIV-infected men.
Cross-sectional cohort using direct measurement of glomerular filtration rate (GFR) by iohexol plasma clearance for 367 HIV-infected men and 241 HIV-uninfected men who were free of CKD.
Hyperfiltration was defined as GFR >140 ml/min/1.73m2 - 1 ml/min/1.73m2 per each year over age 40. Multivariate logistic regression was used to estimate the odds ratios (OR) of prevalent hyperfiltration for metabolic, cardiovascular, HIV and cumulative ART exposure factors.
Among subjects without CKD, the prevalence of hyperfiltration was higher for HIV-infected participants (25%) compared to uninfected participants (17%; p=0.01). HIV infection was associated with hyperfiltration (OR: 1.70, 95%CI: 1.11, 2.61) and modified the association between diabetes and hyperfiltration, such that the association among HIV-uninfected men (OR: 2.56 95%CI: 1.33, 5.54) was not observed among HIV-infected men (OR: 1.19, 95%CI: 0.69, 2.05). These associations were independent of known risk factors for hyperfiltration. Indicators of hyperglycemia and hypertension were also associated with hyperfiltration as was cumulative zidovudine exposure.
Hyperfiltration, a potential modifiable predictor of kidney disease progression, is common among ART-treated HIV-infected men. HIV infection is associated with significant odds of hyperfiltration in addition to known risk factors for kidney damage.
Glomerular hyperfiltration; glomerular filtration rate; HIV; antiretroviral therapy; iohexol
In the context of HIV, the initiation of effective antiretroviral therapy (ART) has been found to increase the risk of dyslipidemia in HIV-infected individuals, and dyslipidemia has been found to be a risk factor for kidney disease in the general population. Therefore, we examined changes in lipid profiles in HIV-infected men following ART initiation and the association with future kidney dysfunction. HIV-infected men from the Multicenter AIDS Cohort Study initiating ART between December 31, 1995 and September 30, 2011 with measured lipid and serum creatinine values pre-ART and post-ART were selected. The associations between changes in total cholesterol or high-density lipoprotein following ART initiation and the estimated change in glomerular filtration rate (eGFR) over time were assessed using piecewise linear mixed effects models. There were 365 HIV-infected men who contributed to the analysis. In the adjusted models, at 3 years post-ART, those with changes in total cholesterol >50 mg/dl had an average decrease in eGFR of 2.6 ml/min/1.73 m2 per year (p<0.001) and at 5 years post-ART, the average decrease was 2.4 ml/min/1.73 m2 per year (p=0.008). This decline contrasted with the estimates for those with changes in total cholesterol ≤50 mg/dl: 1.4 ml/min/1.73 m2 decrease per year (p<0.001) and 0.1 ml/min/1.73 m2 decrease per year (p=0.594) for the same time periods, respectively. Large decreases in high-density lipoprotein (a decline of greater than 5 mg/dl) were not associated with declines in eGFR. These results indicate that large ART-related increases in total cholesterol may be a risk factor for kidney function decline in HIV-infected men. Should these results be generalizable to the broader HIV population, monitoring cholesterol changes following the initiation of ART may be important in identifying HIV-infected persons at risk for kidney disease.
Body fat changes in HIV-infected persons are associated with increased systemic inflammation and increased mortality. It is unknown whether lipodystrophy is also associated with declines in physical function. Between 2001 and 2003, 33 HIV-infected men with evidence of lipodystrophy (LIPO+), 23 HIV-infected men without lipodystrophy (LIPO−), and 33 seronegative men were recruited from the Multicenter AIDS Cohort Study (MACS) for the Body Composition substudy. Visceral adipose tissue (VAT) was assessed by quantitative computed tomography. Lean body mass (LBM) and extremity fat were measured by dual-energy x-ray absorptiometry. Insulin resistance was estimated by Homeostatic Model Assessment (HOMA). Serum interleukin (IL)-6, soluble tumor necrosis factor (TNF)-α receptors I and II (sTNFRI and sTNFRII), and highly sensitive C-reactive protein (hs-CRP) concentrations were quantified from archived serum samples. These measurements were correlated with grip strength measured in 2007 using linear regression. At the substudy visit, the LIPO+ group had higher HOMA, sTNFRI, sTNFRII, and IL-6 levels than the LIPO− group. In 2007, the LIPO+ group had lower median grip strength than the LIPO− group (34.4 vs. 42.7 kg, p=0.002). Multivariable analysis of HIV+ men showed older age, lower LBM, higher sTNFRII concentrations, and LIPO+ status [adjusted mean difference −4.9 kg (p=0.045)] at the substudy visit were independently associated with lower subsequent grip strength. Inflammation, lower LBM, and lipodystrophy in HIV-infected men were associated with lower subsequent grip strength. These findings suggest that inflammation may contribute to declines in functional performance, independent of age.
To test the predictive accuracy of the Framingham Risk Score for Stroke (FRS-S) in HIV-infected (HIV+) vs HIV-uninfected (HIV−) men.
The Multicenter AIDS Cohort Study (MACS) is an ongoing prospective study of HIV+ and HIV− men who have sex with men (MSM) enrolled in 4 US cities. We ascertained all reported stroke events during a recent 15-year timeframe (July 1, 1996 to June 30, 2011) among 3,945 participants (1,776 HIV+ and 2,169 HIV−). For those with strokes, FRS-S were calculated 10 years before the stroke event and assessed according to HIV status.
A total of 114 stroke events occurred, including 57 HIV+ and 37 HIV− participants with first-ever strokes and 19 fatal strokes. The incidence of first-ever stroke was 1.7/1,000 person-years among HIV− and 3.3/1,000 person-years among HIV+ participants. Among those with strokes, HIV+ participants were younger than HIV− participants (median age 51.3 vs 61.8 years, p < 0.0001). For these men with stroke, the average 10-year risk of stroke was higher for HIV− MSM (6.6% [range 3%–26%] vs 4.9% for HIV+ MSM [range 0%–15%], p < 0.04). Traditional risk factors for stroke were similar among the Framingham cohort and the MACS HIV+ and HIV− participants.
FRS-S prediction was systematically different in HIV+ vs HIV− men with stroke events. The FRS-S underestimates the long-term risk of stroke in HIV+ men.
Highly active antiretroviral therapy (HAART) has been successful in delaying the progression to AIDS in HIV-1-infected individuals. Exposure to HAART can result in metabolic side effects, such as dyslipidemia, in a subset of recipients. Longitudinal data and frozen peripheral blood mononuclear cell pellets were obtained from 1,945 men enrolled in the Multicenter AIDS Cohort. Individuals were genotyped for ancestry informative markers (AIMs) and stratified by biogeographical ancestry (BGA). Then serum levels of total cholesterol (TCHOL), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TRIG) were examined controlling for a number of HIV and HAART-related covariates using multivariate mixed-effects linear regression. HIV-1 infection, in the absence of HAART, was associated with altered lipid levels for all phenotypes tested when compared to HIV-negative men. HIV-1-infected men receiving HAART also had significantly different lipid levels compared to HIV-negative men, except for LDL-C. There were statistically significant interactions between BGA and HIV/HAART status for all lipids tested. BGA remained significantly associated with lipid levels after controlling for other HIV and HAART-related covariates. There was low concordance between self-reported race (SRR) and BGA in admixed populations. BGA performed better than SRR in our statistical models. Lipid profiles in untreated HIV-1-positive men and HIV-1-positive men receiving HAART differ from HIV-negative men and this effect varies by BGA. BGA performed better in our statistical analysis as a racial classifier but SRR remains a good clinical surrogate for BGA.
Natural history studies suggest increased risk for kidney function decline with HIV infection, but few studies have made comparisons with HIV-uninfected women. We examined whether HIV infection treated with highly active antiretroviral therapy (HAART) remains associated with faster kidney function decline in the Women's Interagency HIV Study. HIV-infected women initiating HAART with (n=105) or without (n=373) tenofovir (TDF) were matched to HIV-uninfected women on calendar and length of follow-up, age, systolic blood pressure, hepatitis C antibody serostatus, and diabetes history. Linear mixed models were used to evaluate differences in annual estimated glomerular filtration rate (eGFR). Person-visits were 4,741 and 11,512 for the TDF-treated and non-TDF-treated analyses, respectively. Mean baseline eGFRs were higher among women initiated on TDF-containing HAART and lower among those on TDF-sparing HAART compared to their respective HIV-uninfected matches (p<0.05 for both). HIV-infected women had annual rates of eGFR changes similar to HIV-uninfected matches (p-interaction >0.05 for both). Adjusting for baseline eGFR, mean eGFRs at 1 and 3 years of follow-up among women initiated on TDF-containing HAART were lower than their uninfected matches (−4.98 and −4.26 ml/min/1.73 m2, respectively; p<0.05 for both). Mean eGFR of women initiated on TDF-sparing HAART was lower versus uninfected matches at 5 years (–2.19 ml/min/1.73 m2, p=0.03). HAART-treated HIV-infected women had lower mean eGFRs at follow-up but experienced rates of annual eGFR decline similar to HIV-uninfected women. Tenofovir use in HIV-infected women with normal kidney function did not accelerate long-term kidney function decline relative to HIV-uninfected women.
In the last decade, timely initiation of antiretroviral therapy and resulting virologic suppression have greatly improved in North America concurrent with the development of better tolerated and more potent regimens, but significant barriers to treatment uptake remain.
Background. Since the mid-1990s, effective antiretroviral therapy (ART) regimens have improved in potency, tolerability, ease of use, and class diversity. We sought to examine trends in treatment initiation and resulting human immunodeficiency virus (HIV) virologic suppression in North America between 2001 and 2009, and demographic and geographic disparities in these outcomes.
Methods. We analyzed data on HIV-infected individuals newly clinically eligible for ART (ie, first reported CD4+ count <350 cells/µL or AIDS-defining illness, based on treatment guidelines during the study period) from 17 North American AIDS Cohort Collaboration on Research and Design cohorts. Outcomes included timely ART initiation (within 6 months of eligibility) and virologic suppression (≤500 copies/mL, within 1 year). We examined time trends and considered differences by geographic location, age, sex, transmission risk, race/ethnicity, CD4+ count, and viral load, and documented psychosocial barriers to ART initiation, including non–injection drug abuse, alcohol abuse, and mental illness.
Results. Among 10 692 HIV-infected individuals, the cumulative incidence of 6-month ART initiation increased from 51% in 2001 to 72% in 2009 (Ptrend < .001). The cumulative incidence of 1-year virologic suppression increased from 55% to 81%, and among ART initiators, from 84% to 93% (both Ptrend < .001). A greater number of psychosocial barriers were associated with decreased ART initiation, but not virologic suppression once ART was initiated. We found significant heterogeneity by state or province of residence (P < .001).
Conclusions. In the last decade, timely ART initiation and virologic suppression have greatly improved in North America concurrent with the development of better-tolerated and more potent regimens, but significant barriers to treatment uptake remain, both at the individual level and systemwide.
antiretroviral therapy; healthcare disparities; HIV; time factors; viral load
HIV infection and low CD4+ T-cell count are associated with an increased risk of persistent oncogenic HPV infection – the major risk factor for cervical cancer. Few reported prospective cohort studies have characterized the incidence of invasive cervical cancer (ICC) in HIV-infected women.
Data were obtained from HIV-infected and -uninfected female participants in the NA-ACCORD with no history of ICC at enrollment. Participants were followed from study entry or January, 1996 through ICC, loss-to follow-up or December, 2010. The relationship of HIV infection and CD4+ T-cell count with risk of ICC was assessed using age-adjusted Poisson regression models and standardized incidence ratios (SIR). All cases were confirmed by cancer registry records and/or pathology reports. Cervical cytology screening history was assessed through medical record abstraction.
A total of 13,690 HIV-infected and 12,021 HIV-uninfected women contributed 66,249 and 70,815 person-years (pys) of observation, respectively. Incident ICC was diagnosed in 17 HIV-infected and 4 HIV-uninfected women (incidence rate of 26 and 6 per 100,000 pys, respectively). HIV-infected women with baseline CD4+ T-cells of ≥ 350, 200–349 and <200 cells/uL had a 2.3-times, 3.0-times and 7.7-times increase in ICC incidence, respectively, compared with HIV-uninfected women (Ptrend =0.001). Of the 17 HIV-infected cases, medical records for the 5 years prior to diagnosis showed that 6 had no documented screening, 5 had screening with low grade or normal results, and 6 had high-grade results.
This study found elevated incidence of ICC in HIV-infected compared to -uninfected women, and these rates increased with immunosuppression.
Human papilloma virus; HIV-infection; Invasive Cervical Cancer; Immunosuppression
Tenofovir has been associated with renal tubular injury. Biomarkers that signal early tubular dysfunction are needed because creatinine rise lags behind tenofovir-associated kidney dysfunction. We examined several urinary biomarkers to determine if rises accompanying tenofovir initiation preceded creatinine changes.
Three urinary biomarkers of tubular impairment- neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl- β -D-glucosaminidase (NAG), and β-2-microglobulin (β2MG)-were measured across three time points (one pre-tenofovir visit and two post tenofovir visits) in one hundred and thirty two HIV-positive women from the Women's Interagency HIV Study (WIHS). Women initiating HAART containing tenofovir were propensity score matched to women initiating HAART without tenofovir and women not on HAART.
There were no differences between groups for NGAL or NAG but β2MG was 19 times more likely to be elevated among tenofovir users at the 2nd post tenofovir visit compared to non-TDF users at the pre-tenofovir visit (p<0.01). History of proteinuria was associated with elevated NGAL (p <0.01). Factors associated with elevated NAG were GFR<60 ml/min, history of proteinuria, hepatitis C (p<0.01 for all) and diabetes mellitus (p=0.05). Factors associated with increased odds of elevated β2MG were HIV RNA>100,000 copies/ml, hepatitis C, boosted protease inhibitor (PI) use, and GFR<60 ml/min (p≤0.01 for all).
β2MG levels are elevated in women on tenofovir indicating probable early renal dysfunction. Biomarker elevation is additionally associated with baseline chronic kidney disease, uncontrolled viremia, and boosted PI use. Future studies are needed to explore urinary biomarker thresholds in identifying treated HIV-infected individuals at risk for renal dysfunction.
Tenofovir; urinary biomarkers; HIV infected women
In HIV-infected women, urine concentrations of novel tubulointerstitial injury markers, interleukin-18 (IL-18) and kidney injury marker-1 (KIM-1) are associated with kidney function decline and all-cause mortality. We hypothesized that HIV-infected individuals with preserved kidney filtration function would have more extensive kidney injury, as determined by urine injury markers, compared to the uninfected controls, and that risk factors for tubulointerstitial injury would differ from risk factors for albuminuria.
In this cross-sectional study, we compared urine concentrations of IL-18, KIM-1, and ACR in 908 HIV-infected and 289 HIV-uninfected women enrolled in the Women’s Interagency HIV Study, utilizing stored urine specimens from visits between 1999 and 2000.
After multivariate-adjusted linear regression analysis, mean urine concentrations were higher in HIV-infected individuals by 38% for IL-18 (p<0.0001), 12% for KIM-1 (p=0.081), and 47% for ACR (p<0.0001). Higher HIV RNA level (15% per 10-fold increase, p<0.0001), lower CD4 count (8% per doubling, p=0.0025), HCV infection (30%, p=0.00018), and lower HDL (5% per 10 mg/dL, p=0.0024) were each associated with higher IL-18 concentrations. In contrast, hypertension (81%, p<0.0001) and diabetes (47%, p=0.018) were among the strongest predictors of higher ACR, though HIV RNA level (15% per 10-fold increase, p=0.0004) was also associated with higher ACR.
HIV-infected women had more extensive tubulointerstitial and glomerular injury than uninfected women, but the associated factors differed among the urine biomarkers. Combinations of urinary biomarkers should be investigated to further characterize early kidney injury in HIV-infected women.
Cystatin C could improve chronic kidney disease (CKD) classification in HIV-infected women relative to serum creatinine.
Retrospective cohort analysis.
Cystatin C and creatinine were measured from specimens taken and stored during the 1999–2000 exam among 908 HIV-infected participants in the Women’s Interagency HIV study (WIHS). Mean follow-up was 10.2 years. The associations of baseline categories (<60, 60–90, and >90 mL/min/1.73m2) of creatinine eGFR (eGFRcr), cystatin C eGFR (eGFRcys), and combined creatinine-cystatin C eGFR (eGFRcr-cys) with all-cause mortality were evaluated using multivariable Cox regression. The net reclassification index (NRI) was calculated to evaluate the effect of cystatin C on reclassification of CKD staging.
The prevalence of CKD (eGFR<60) at baseline was higher with eGFRcys (10.1%) compared to eGFRcr (6.7%, p=0.0006) and eGFRcr-cys (7.5%, p=0.011). Relative to eGFR >90, the eGFR <60 category by eGFRcys (Adjusted HR: 2.56; 95% CI: 1.63, 4.02), eGFRcr-cys (3.11; 1.94–5.00), and eGFRcr (2.34; 1.44–3.79) was associated with increased mortality risk. However, the eGFR 60–90 category was associated with increased mortality risk for eGFRcys (1.80; 1.28–2.53) and eGFRcr-cys (1.91; 1.38–2.66) but not eGFRcr (1.20; 0.85–1.67). The overall NRI for mortality was 26% when reclassifying from eGFRcr to eGFRcys (p<0.001) and was 20% when reclassifying from eGFRcr to eGFRcr-cys (p<0.001).
Cystatin C detected a higher prevalence of CKD relative to creatinine and improves CKD staging relative to creatinine by reclassifying individuals at the highest mortality risk to lower eGFR categories.
Creatinine; Cystatin C; Glomerular Filtration Rate; HIV; Mortality; Kidney; Women
Formulae used to estimate glomerular filtration rate (GFR) underestimate higher GFRs and have not been well-studied in HIV-infected (HIV(+)) people; we evaluated the relationships of HIV infection and known or potential risk factors for kidney disease with directly measured GFR and the presence of chronic kidney disease (CKD).
Cross-sectional measurement of iohexol-based GFR (iGFR) in HIV(+) men (n = 455) receiving antiretroviral therapy, and HIV-uninfected (HIV(−)) men (n = 258) in the Multicenter AIDS Cohort Study.
iGFR was calculated from disappearance of infused iohexol from plasma. Determinants of GFR and the presence of CKD were compared using iGFR and GFR estimated by the CKD-Epi equation (eGFR).
Median iGFR was higher among HIV(+) than HIV(−) men (109 vs. 106 ml/min/1.73 m2, respectively, p = .046), and was 7 ml/min higher than median eGFR. Mean iGFR was lower in men who were older, had chronic hepatitis C virus (HCV) infection, or had a history of AIDS. Low iGFR (≤90 ml/min/1.73 m2) was associated with these factors and with black race. Other than age, factors associated with low iGFR were not observed with low eGFR. CKD was more common in HIV(+) than HIV(−) men; predictors of CKD were similar using iGFR and eGFR.
iGFR was higher than eGFR in this population of HIV-infected and -uninfected men who have sex with men. Presence of CKD was predicted equally well by iGFR and eGFR, but associations of chronic HCV infection and history of clinically-defined AIDS with mildly decreased GFR were seen only with iGFR.
HIV-infected persons have substantially higher risk of kidney failure than persons without HIV, but serum creatinine levels are insensitive for detecting declining kidney function. We hypothesized that urine markers of kidney injury would be associated with declining kidney function among HIV-infected women.
In the Women's Interagency HIV Study (WIHS), we measured concentrations of albumin-to-creatinine ratio (ACR), interleukin-18 (IL-18), kidney injury marker-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) from stored urine among 908 HIV-infected and 289 uninfected participants. Primary analyses used cystatin C based estimated glomerular filtration rate (CKD-EPI eGFRcys) as the outcome, measured at baseline and two follow-up visits over eight years; secondary analyses used creatinine (CKD-EPI eGFRcr). Each urine biomarker was categorized into tertiles, and kidney decline was modeled with both continuous and dichotomized outcomes.
Compared with the lowest tertiles, the highest tertiles of ACR (−0.15ml/min/1.73m2, p<0.0001), IL-18 (−0.09ml/min/1.73m2, p<0.0001) and KIM-1 (−0.06ml/min/1.73m2, p<0.001) were independently associated with faster eGFRcys decline after multivariate adjustment including all three biomarkers among HIV-infected women. Among these biomarkers, only IL-18 was associated with each dichotomized eGFRcys outcome: ≥3% (Relative Risk 1.40; 95%CI 1.04-1.89); ≥5% (1.88; 1.30-2.71); and ≥10% (2.16; 1.20-3.88) for the highest versus lowest tertile. In alternative models using eGFRcr, the high tertile of KIM-1 had independent associations with 5% (1.71; 1.25-2.33) and 10% (1.78; 1.07-2.96) decline, and the high IL-18 tertile with 10% decline (1.97; 1.00-3.87).
Among HIV-infected women in the WIHS cohort, novel urine markers of kidney injury detect risk for subsequent declines in kidney function.
HIV; KIM-1; NGAL; IL-18; albumin-to-creatinine ratio; cystatin C; kidney injury
Chronic kidney disease and HIV infection both independently increase the risk of anemia. It is not known if individuals with both HIV infection and kidney dysfunction are at greater than expected risk of anemia resulting from the combined effect of these factors. Men from the Multicenter AIDS Cohort Study with AIDS-free time after 1996 were included in the analysis if they had an initial hemoglobin value greater than 13 g/dl and available serum creatinine measurements for the estimation of glomerular filtration rate. Hemoglobin data were fit parametrically using a linear mixed effects model and effects of medication use on hemoglobin levels were removed using censoring methods. The effect of both HIV infection and glomerular filtration rate less than 60 ml/min/1.73 m2 on the mean hemoglobin value was assessed. The risk of having anemia (hemoglobin level falling below 13 g/dl) was estimated. There were 862 HIV-infected and 1,214 HIV-uninfected men who contributed to the analysis. Hemoglobin values across all 17,341 person-visits, adjusting for age, were generally lower in HIV-infected AIDS-free men with impaired kidney function by −0.22 g/dl (95% CI: −0.42, −0.03) compared to men with either HIV infection or impaired kidney function, but not both. HIV-infected AIDS-free men with impaired kidney function have a higher risk of anemia by 1.2% compared to HIV-uninfected men with normal kidney function. Comorbid conditions and medication use did not explain this increase in risk. HIV infection and impaired kidney function have a combined impact on lowering hemoglobin levels, resulting in a higher risk of anemia.
Serum ferritin and transferrin saturation (TSAT) are used to assess iron status in children with chronic kidney disease (CKD), but their sensitivity in identifying those at risk of lower hemoglobin (HGB) values is unclear.
We assessed the association of iron status markers (ferritin, TSAT, and serum iron) with age- and gender-related HGB percentile in mild-to-moderate CKD in 304 children in the Chronic Kidney Disease in Children (CKiD) Study. Standardized HGB percentile values were examined by KDOQI-recommended ferritin (≥100 ng/ml) and TSAT (≥20 %) thresholds. Regression tree methods were used to identify iron status markers and clinical characteristics most associated with lower HGB percentiles.
The cohort was 62 % male, 23 % African American, and 12 % Hispanic, median age 12 years, and median HGB 12.9 g/dl. 34 % had low TSAT and 93 % low ferritin as defined by KDOQI. Distribution of HGB percentile values was lower in those with ferritin ≥100 ng/ml, while TSAT ≥20 % was associated with only modest increase in HGB percentile. In regression tree analysis, lower glomerular filtration rate (GFR), serum iron <50 μg/dl and ferritin ≥100 ng/ml were most strongly associated with lower HGB percentile.
The level of GFR was significantly associated with HGB. Higher serum ferritin was associated with lower HGB in this cohort. Low serum iron in the context of normal/increased ferritin and low HGB may be a useful indicator of iron-restricted erythropoiesis.
Chronic kidney disease; Hemoglobin; Iron deficiency; Anemia
More than two-thirds of the world's HIV-positive individuals live in sub-Saharan Africa, where genetic susceptibility to kidney disease is high and resources for kidney disease screening and antiretroviral therapy (ART) toxicity monitoring are limited. Equations to estimate glomerular filtration rate (GFR) from serum creatinine were derived in Western populations and may be less accurate in this population.
We compared results from published GFR estimating equations with a direct measure of GFR by iohexol clearance in 99 HIV-infected, ART-naïve Kenyan adults. Iohexol concentration was measured from dried blood spots on filter paper. The bias ratio (mean of the ratio of estimated to measured GFR) and accuracy (percentage of estimates within 30% of the measured GFR) were calculated.
The median age was 35 years, and 60% were women. The majority had asymptomatic HIV, with median CD4+ cell count of 355 cells/mm3. Median measured GFR was 115 mL/min/1.73 m2. Overall accuracy was highest for the Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation. Consistent with a prior report, bias and accuracy were improved by eliminating the coefficient for black race (85% of estimates within 30% of measured GFR). Accuracy of all equations was poor in participants with GFR 60–90 mL/min/1.73 m2 (<65% of estimates within 30% of measured GFR), although this subgroup was too small to reach definitive conclusions.
Overall accuracy was highest for the CKD-EPI equation. Eliminating the coefficient for race further improved performance. Future studies are needed to determine the most accurate GFR estimate for use in individuals with GFR <90 mL/min/1.73 m2, in whom accurate estimation of kidney function is important to guide drug dosing. Direct measurement of GFR by iohexol clearance using a filter paper based assay is feasible for research purposes in resource-limited settings, and could be used to develop more accurate GFR estimates in African populations.
In adults with chronic kidney disease (CKD), cigarette smoking is associated with an increased risk for CKD progression and transplant failure. In children, secondhand smoke (SHS) exposure has been associated with elevated blood pressure. There are no studies on the prevalence and effect of SHS exposure in CKD.
Subjects were enrolled in the Chronic Kidney Disease in Children (CKiD) Study, an observational cohort of 366 children aged 1 to 16 years with CKD. Secondhand smoke exposure was obtained via questionnaire. SHS exposure was also determined based on urine cotinine (Ucot) measurements (1 ng/mL≤Ucot<75 ng/mL). The cross-sectional association of SHS exposure with proteinuria was assessed.
Using Ucot, 22 % of subjects were exposed to SHS. SHS exposure was significantly associated with lower maternal education and African American race, and a greater prevalence of nephrotic range proteinuria and left ventricular hypertrophy. In a multivariate model (including sex, age, race, maternal education, income level, private insurance status, abnormal birth history and CKD diagnosis), the prevalence odds of nephrotic range proteinuria was 2.64, (95 % confidence interval 1.08, 6.42) higher in children exposed to SHS compared to those unexposed.
In our cohort of children with CKD, SHS exposure was common (22 %) and independently associated with nephrotic range proteinuria. Exposure to SHS may be an important factor to consider in CKD progression.
Proteinuria; Tobacco use; Chronic kidney disease progression; Secondhand smoke exposure; Urine cotinine; Pediatric chronic kidney disease
Background: The role of environmental exposure to lead as a risk factor for chronic kidney disease (CKD) and its progression remains controversial, and most studies have been limited by a lack of direct glomerular filtration rate (GFR) measurement.
Objective: We evaluated the association between lead exposure and GFR in children with CKD.
Methods: In this cross-sectional study, we examined the association between blood lead levels (BLLs) and GFR measured by the plasma disappearance of iohexol among 391 participants in the Chronic Kidney Disease in Children (CKiD) prospective cohort study.
Results: Median BLL and GFR were 1.2 µg/dL and 44.4 mL/min per 1.73 m2, respectively. The average percent change in GFR for each 1-µg/dL increase in BLL was –2.1 (95% CI: –6.0, 1.8). In analyses stratified by CKD diagnosis, the association between BLL and GFR was stronger among children with glomerular disease underlying CKD; in this group, each 1-µg/dL increase in BLL was associated with a –12.1 (95% CI: –22.2, –1.9) percent change in GFR. In analyses stratified by anemia status, each 1-µg/dL increase in BLL among those with and without anemia was associated with a –0.3 (95% CI: –7.2, 6.6) and –4.6 (95% CI: –8.9, –0.3) percent change in GFR, respectively.
Conclusions: There was no significant association between BLL and directly measured GFR in this relatively large cohort of children with CKD, although associations were observed in some subgroups. Longitudinal analyses are needed to examine the temporal relationship between lead and GFR decline, and to further examine the impact of underlying cause of CKD and anemia/hemoglobin status among patients with CKD.
children; chronic kidney disease; kidney; lead; nephrotoxicity; pediatric
Data from 1790 HIV-infected and uninfected men in the Multicenter AIDS Cohort Study (MACS) were analyzed to evaluate relationships between physical function, incident diabetes mellitus (DM) and insulin resistance among HIV-infected and -uninfected men. DM was defined in two ways, using less stringent and more stringent criteria. The 10-item Physical Functioning Scale from the Short Form-36 Health Survey measured baseline physical function. Cumulative DM incidence was highest among HIV-uninfected and HIV-infected men with low physical function. Physical function was a risk factor for DM in HIV-uninfected men and remained so after controlling for BMI, DM family history and race. Among HIV-infected men, physical function was an independent risk factor for DM using the less stringent diabetes definition. This study supports our previous findings that low physical function is an important risk factor for DM in the MACS cohort.
AIDS; diabetes mellitus; HIV; insulin resistance; physical function
To compare the health related quality of life (HRQOL) of children with chronic kidney disease (CKD) to healthy children; to evaluate the association between CKD severity and HRQOL; to identity demographic, socioeconomic and health-status variables associated with impairment in HRQOL in children with mild to moderate CKD.
Patients and Methods
This is a cross-sectional assessment of HRQOL in children aged 2-16 with mild to moderate CKD using the Varni PedsQL™. Overall HRQOL and PedsQL domain means for parents and youth were compared to previously published norms using independent sample t-tests. Study participants were categorized according to kidney disease stage (measured by iohexol based glomerular filtration rate, iGFR) and group differences in HRQOL were evaluated using ANOVA and Cuzick trend tests. The association between hypothesized predictors of HRQOL and PedsQL scores was evaluated with linear and logistic regression analyses.
The study sample was comprised of 402 participants (Mean age =11 yrs, 60% male, 70% Caucasian, 40% anemic, median iGFR=42.5 ml/min/1.73m2, median CKD duration= 7 yrs). Youth with CKD had significantly lower physical, school, emotional and social domain scores than healthy youth (p<.001). IGFR was not associated with HRQOL. Longer disease duration and older age was associated with higher PedsQL scores in the domains of physical, emotional and social functioning (p<.05). Older age was associated with lower school functioning domain scores (p<.05). Maternal education ≥16 years was associated with higher PedsQL scores in the domains of physical, school, and social functioning (p<.05). Short stature was associated with lower scores in the physical functioning domain (p<.05).
Children with mild to moderate CKD, in comparison to healthy children, report poorer overall HRQOL as well as poorer physical, school, emotional and social functioning. Early intervention to improve linear growth and to address school functioning difficulties is recommended.
HRQOL; kidney disease; QOL; short-stature
Fungal load quantification is a critical component of fungal community analyses. Limitation of current approaches for quantifying the fungal component in the human microbiome suggests the need for new broad-coverage techniques.
We analyzed 2,085 18S rRNA gene sequences from the SILVA database for assay design. We generated and quantified plasmid standards using a qPCR-based approach. We evaluated assay coverage against 4,968 sequences and performed assay validation following the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines.
We designed FungiQuant, a TaqMan® qPCR assay targeting a 351 bp region in the fungal 18S rRNA gene. Our in silico analysis showed that FungiQuant is a perfect sequence match to 90.0% of the 2,617 fungal species analyzed. We showed that FungiQuant’s is 100% sensitive and its amplification efficiencies ranged from 76.3% to 114.5%, with r2-values of >0.99 against the 69 fungal species tested. Additionally, FungiQuant inter- and intra-run coefficients of variance ranged from <10% and <20%, respectively. We further showed that FungiQuant has a limit of quantification 25 copies and a limit of detection at 5 copies. Lastly, by comparing results from human-only background DNA with low-level fungal DNA, we showed that amplification in two or three of a FungiQuant performed in triplicate is statistically significant for true positive fungal detection.
FungiQuant has comprehensive coverage against diverse fungi and is a robust quantification and detection tool for delineating between true fungal detection and non-target human DNA.
Determination of the prevalence of accumulated antiretroviral drug resistance among persons infected with human immunodeficiency virus (HIV) is complicated by the lack of routine measurement in clinical care. By using data from 8 clinic-based cohorts from the North American AIDS Cohort Collaboration on Research and Design, drug-resistance mutations from those with genotype tests were determined and scored using the Genotypic Resistance Interpretation Algorithm developed at Stanford University. For each year from 2000 through 2005, the prevalence was calculated using data from the tested subset, assumptions that incorporated clinical knowledge, and multiple imputation methods to yield a complete data set. A total of 9,289 patients contributed data to the analysis; 3,959 had at least 1 viral load above 1,000 copies/mL, of whom 2,962 (75%) had undergone at least 1 genotype test. Using these methods, the authors estimated that the prevalence of accumulated resistance to 2 or more antiretroviral drug classes had increased from 14% in 2000 to 17% in 2005 (P < 0.001). In contrast, the prevalence of resistance in the tested subset declined from 57% to 36% for 2 or more classes. The authors’ use of clinical knowledge and multiple imputation methods revealed trends in HIV drug resistance among patients in care that were markedly different from those observed using only data from patients who had undergone genotype tests.
antiretroviral therapy, highly active; drug resistance; genotype; HIV
Immune responses to Pneumocystis jirovecii are not well understood in HIV infection, but antibody responses to proteins may be useful as a marker of Pneumocystis risk or presence of Pneumocystis pneumonia (PcP).
Retrospective analysis of a prospective cohort
Enzyme-linked immunosorbent assays of antibodies to recombinant Pneumocystis proteins of major surface glycoprotein fragments (MsgC1, C3, C8, and C9) and of antibody titers to recombinant kexin protein (KEX1) were performed on three sequential serum samples up to 18 months prior to and three samples after first AIDS-defining illness from Multicenter AIDS Cohort Study participants and compared between those who had PcP or a non-PcP AIDS-defining illness.
Fifty-four participants had PcP and 47 had a non-PcP AIDS-defining illness. IgG levels to MsgC fragments were similar between groups prior to first AIDS-defining illness, but the PcP group had higher levels of IgG to MsgC9 (median units/ml 50.2 vs. 22.2, p=0.047) post-illness. Participants with PcP were more likely to have an increase in MsgC3 (OR 3.9, p=0.02), MsgC8 (OR 5.5, p=0.001), and MsgC9 (OR 4.0, p=0.007). The PcP group was more likely to have low KEX1 IgG prior to development of PcP (OR 3.6, p=0.048) independent of CD4 cell count and to have an increase in high IgG titers to KEX1 after PcP.
HIV-infected individuals develop immune responses to both Msg and kexin proteins after PcP. Low KEX1 IgG titers may be a novel marker of future PcP risk before CD4 cell count has declined below 200 cells/μl.
HIV; Acquired Immunodeficiency Syndrome; Pneumocystis; serology
In the early highly active antiretroviral therapy (HAART) era, kidney dysfunction was strongly associated with death among HIV-infected individuals. We re-examined this association in the later HAART period to determine whether chronic kidney disease (CKD) remains a predictor of death after HAART-initiation.
To evaluate the effect of kidney function at the time of HAART initiation on time to all-cause mortality, we evaluated 1415 HIV-infected women initiating HAART in the Women’s Interagency HIV Study (WIHS). Multivariable proportional hazards models with survival times calculated from HAART initiation to death were constructed; participants were censored at the time of the last available visit or December 31, 2006.
CKD (eGFR <60 ml/min/1.73 m2) at HAART initiation was associated with higher mortality risk adjusting for age, race, hepatitis C serostatus, AIDS history and CD4+ cell count (hazard ratio [HR]=2.23, 95% confidence interval [CI]: 1.45–3.43). Adjustment for hypertension and diabetes history attenuated this association (HR=1.89, CI: 0.94–3.80). Lower kidney function at HAART initiation was weakly associated with increased mortality risk in women with prior AIDS (HR=1.09, CI: 1.00–1.19, per 20% decrease in eGFR).
Kidney function at HAART initiation remains an independent predictor of death in HIV-infected individuals, especially in those with a history of AIDS. Our study emphasizes the necessity of monitoring kidney function in this population. Additional studies are needed to determine mechanisms underlying the increased mortality risk associated with CKD in HIV-infected persons.
kidney disease; mortality; HIV; WIHS; antiretroviral therapy