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1.  Algorithm for analysis of administrative pediatric cancer hospitalization data according to indication for admission 
Childhood cancer relies heavily on inpatient hospital services to deliver tumor-directed therapy and manage toxicities. Hospitalizations have increased over the past decade, though not uniformly across childhood cancer diagnoses. Analysis of the reasons for admission of children with cancer could enhance comparison of resource use between cancers, and allow clinical practice data to be interpreted more readily. Such comparisons using nationwide data sources are difficult because of numerous subdivisions in the International Classification of Diseases Clinical Modification (ICD-9) system and inherent complexities of treatments. This study aimed to develop a systematic approach to classifying cancer-related admissions in administrative data into categories that reflected clinical practice and predicted resource use.
We developed a multistep algorithm to stratify indications for childhood cancer admissions in the Kids Inpatient Databases from 2003, 2006 and 2009 into clinically meaningful categories. This algorithm assumed that primary discharge diagnoses of cancer or cytopenia were insufficient, and relied on procedure codes and secondary diagnoses in these scenarios. Clinical Classification Software developed by the Healthcare Cost and Utilization Project was first used to sort thousands of ICD-9 codes into 5 mutually exclusive diagnosis categories and 3 mutually exclusive procedure categories, and validation was performed by comparison with the ICD-9 codes in the final admission indication. Mean cost, length of stay, and costs per day were compared between categories of indication for admission.
A cohort of 202,995 cancer-related admissions was grouped into four categories of indication for admission: chemotherapy (N=77,791, 38%), to undergo a procedure (N=30,858, 15%), treatment for infection (N=30,380, 15%), or treatment for other toxicities (N=43,408, 21.4%). The positive predictive value for the algorithm was >95% for each category. Admissions for procedures had higher mean hospital costs, longer hospital stays, and higher costs per day compared with other admission reasons (p<0.001).
This is the first description of a method for grouping indications for childhood cancer admission within an administrative dataset into clinically relevant categories. This algorithm provides a framework for more detailed analyses of pediatric hospitalization data by cancer type.
Electronic supplementary material
The online version of this article (doi:10.1186/1472-6947-14-88) contains supplementary material, which is available to authorized users.
PMCID: PMC4197316  PMID: 25274165
Cancer; Health administrative data; Healthcare utilization; Child
2.  The Myositis Autoantibody Phenotypes of the Juvenile Idiopathic Inflammatory Myopathies 
Medicine  2013;92(4):223-243.
The juvenile idiopathic inflammatory myopathies (JIIM) are systemic autoimmune diseases characterized by skeletal muscle weakness, characteristic rashes, and other systemic features. In follow-up to our study defining the major clinical subgroup phenotypes of JIIM, we compared demographics, clinical features, laboratory measures, and outcomes among myositis-specific autoantibody (MSA) subgroups, as well as with published data on adult idiopathic inflammatory myopathy patients enrolled in a separate natural history study. In the present study, of 430 patients enrolled in a nationwide registry study who had serum tested for myositis autoantibodies, 374 had either a single specific MSA (n = 253) or no identified MSA (n = 121) and were the subject of the present report. Following univariate analysis, we used random forest classification and exact logistic regression modeling to compare autoantibody subgroups. Anti-p155/140 autoantibodies were the most frequent subgroup, present in 32% of patients with juvenile dermatomyositis (JDM) or overlap myositis with JDM, followed by anti-MJ autoantibodies, which were seen in 20% of JIIM patients, primarily in JDM. Other MSAs, including anti-synthetase, anti-signal recognition particle (SRP), and anti-Mi-2, were present in only 10% of JIIM patients. Features that characterized the anti-p155/140 autoantibody subgroup included Gottron’s papules, malar rash, “shawl-sign” rash, photosensitivity, cuticular overgrowth, lowest creatine kinase (CK) levels, and a predominantly chronic illness course. The features that differed for patients with anti-MJ antibodies included muscle cramps, dysphonia, intermediate CK levels, a high frequency of hospitalization, and a monocyclic disease course. Patients with the anti-synthetase antibody had higher frequencies of interstitial lung disease, arthralgia, and mechanic’s hands, and had an older age at diagnosis. The anti-SRP group, which had exclusively juvenile polymyositis, was characterized by high frequencies of black race, severe onset, distal weakness, falling episodes, Raynaud’s phenomenon, cardiac involvement, high CK levels, chronic disease course, frequent hospitalization, and wheelchair use. Characteristic features of the anti-Mi-2 subgroup included Hispanic ethnicity, classic dermatomyositis and malar rashes, high CK levels, and very low mortality. Finally, the most common features of patients without any currently defined MSA or myositis-associated autoantibodies included linear extensor erythema, arthralgia, and a monocyclic disease course. Several demographic and clinical features were shared between juvenile and adult idiopathic inflammatory myopathy subgroups, but with several important differences. We conclude that juvenile myositis is a heterogeneous group of illnesses with distinct autoantibody phenotypes defined by varying clinical and demographic characteristics, laboratory features, and outcomes.
PMCID: PMC3721421  PMID: 23877355
juvenile myositis; dermatomyositis; polymyositis; overlap myositis; phenotype; myositis autoantibody; Jo1; anti-p155/140 autoantibody; anti-MJ autoantibody; anti-signal recognition particle
3.  Ultraviolet Radiation Exposure is Associated with Clinical and Autoantibody Phenotypes in Juvenile Myositis 
Arthritis and rheumatism  2013;65(7):1934-1941.
Genetic and environmental factors may contribute to the etiology of the juvenile idiopathic inflammatory myopathies (JIIM), systemic autoimmune diseases characterized by muscle and skin inflammation. We investigated the association between ultraviolet radiation (UVR) exposure and the clinical and autoantibody expression of JIIM.
We assessed the relationship between UVR exposure in the month before symptom onset and prevalence of juvenile dermatomyositis (JDM) versus polymyositis (JPM) in 298 patients. Among JDM patients, the association between UVR exposure and myositis autoantibodies was assessed. Regression models were stratified by sex and race. The association between regional UV index in U.S. geoclimatic zones and the clinical and autoantibody subgroups was examined by weighted least squares regression analysis.
We observed increasing odds of JDM compared with JPM per unit increase in the patients’ highest UV index in the month before symptom onset in girls (OR = 1.18; 95% CI = 1.00–1.40). The average and highest UV indices were associated with increasing odds of anti-p155/140 autoantibodies, which was strongest in white males (OR 1.30 and 1.23, respectively). No association was observed between the UV index and anti-MJ autoantibodies or patients without myositis autoantibodies. Across US geoclimatic regions, the average UV index was associated with increasing odds of JDM and anti-p155/140 autoantibodies but decreasing odds of anti-MJ autoantibodies.
Short-term UVR exposure prior to illness onset may have a role in the clinical and serologic expression of juvenile myositis. Research examining mechanisms of UVR in JIIM pathogenesis is suggested from these findings.
PMCID: PMC3727975  PMID: 23658122
ultraviolet radiation; juvenile myositis; dermatomyositis; polymyositis; phenotype; clinical subgroup; myositis; idiopathic inflammatory myopathy; myositis autoantibodies
4.  Health Savings Accounts and Health Care Spending 
Health Services Research  2010;45(4):1041-1060.
The impact of consumer-driven health plans (CDHPs) has primarily been studied in a small number of large, self-insured employers, but this work may not generalize to the wide array of firms that make up the overall economy. The goal of our research is to examine effects of health savings accounts (HSAs) on total, medical, and pharmacy spending for a large number of small and midsized firms.
Data Sources
Health plan administrative data from a national insurer were used to measure spending for 76,310 enrollees over 3 years in 709 employers. All employers began offering a HSA-eligible plan either on a full-replacement basis or alongside traditional plans in 2006 and 2007 after previously offering only traditional plans in 2005.
Study Design
We employ difference-in-differences generalized linear regression models to examine the impact of switching to HSAs.
Data Extraction Methods
Claims data were aggregated to enrollee-years.
Principal Findings
For total spending, HSA enrollees spent roughly 5–7 percent less than non-HSA enrollees. For pharmacy spending, HSA enrollees spent 6–9 percent less than traditional plan enrollees. More of the spending decrease was observed in the first year of enrollment.
Our findings are consistent with the notion that CDHP benefit designs affect decisions that are at the discretion of the consumer, such as whether to fill or refill a prescription, but have less effect on care decisions that are more at the discretion of the provider.
PMCID: PMC2910568  PMID: 20528988
Consumer-driven health plans; high deductible health insurance; health savings accounts; benefit design
5.  Electrophysiological evidence for aging effects on local contextual processing 
We used event-related potentials to investigate how aging affects local contextual processing. Local context was defined as the occurrence of a short predictive series of visual stimuli before delivery of a target event. Stimuli were presented to either the left or right visual field and consisted of 15% targets (downward facing triangle) and 85% of equal numbers of three types of standards (triangles facing left, upwards and right). Recording blocks consisted of targets preceded by either randomized sequences of standards or by sequences including a three-standard predictive sequence signaling the occurrence of a subsequent target event. Subjects pressed a button in response to targets. Predictive local context affected target detection by reducing the duration of stimulus evaluation compared to detection of non-predictive random targets comparably for both young and older adults, as shown by a P3b latency shift. The peak of an earlier latency context positivity, which was seen only in the predicted compared to the random target condition, was prolonged in the older population compared to young adults. Finally, older subjects elicited a late sustained positivity in the predictive condition, not seen in the younger subjects. Taken together, theses findings suggest that local contextual effects on target detection processes are altered with age.
PMCID: PMC2826523  PMID: 19559410
aging; context; P3b; EEG; context positivity
6.  The association between state mandates of colorectal cancer screening coverage and colorectal cancer screening utilization among US adults aged 50 to 64 years with health insurance 
Several states in the US have passed laws mandating coverage of colorectal cancer (CRC) screening tests by health insurance plans. The impact of these state mandates on the use of colorectal cancer screening has not been evaluated among an age-eligible target population with access to care (i.e., health care insurance coverage).
We collected information on state mandates implemented by December 31, 2008 and used data on insured adults aged 50 and 64 years from the Behavioral Risk Factor Surveillance System between 2002 and 2008 to classify individual-level exposure to state mandates for at least 1 year. Multivariate logistic regression models (with state- and year- fixed effects, and patient demographic and socioeconomic characteristics) were used to estimate the effect of state mandates on recent endoscopy screening (either flexible sigmoidoscopy or colonoscopy during the past year).
From 1999-2008, twenty-two states in the US, including the District of Columbia passed comprehensive laws requiring health insurance coverage of CRC screening including endoscopy tests. Residence in states with CRC screening coverage mandates in place for at least 1 year was associated with a 1.4 percentage point increase in the probability of utilization of recent endoscopy (i.e., 17.5% screening rates in those with mandates versus 16.1% in those without, Adjusted OR = 1.10, 95% CI: 1.02 - 1.20, p = 0.02).
The findings suggest a positive, albeit small, impact of state mandates on the use of recent CRC screening endoscopy among the target eligible population with health insurance. However, more research is needed to evaluate potential effects of mandates across health insurance types while including controls for other system-level factors (e.g. endoscopy and primary care capacity). National health insurance reform should strive towards a system that expands access to recommended CRC screening tests.
PMCID: PMC3038893  PMID: 21272321
7.  Prefrontal cortex is critical for contextual processing: evidence from brain lesions 
Brain  2009;132(11):3002-3010.
We investigated the role of prefrontal cortex (PFC) in local contextual processing using a combined event-related potentials and lesion approach. Local context was defined as the occurrence of a short predictive series of visual stimuli occurring before delivery of a target event. Targets were preceded by either randomized sequences of standards or by sequences including a three-stimulus predictive sequence signalling the occurrence of a subsequent target event. PFC lesioned patients were impaired in their ability to use local contextual information. The response time for controls revealed a larger benefit for predictable targets than for random targets relative to PFC patients. PFC patients had reduced amplitude of a context-dependent positivity and failed to generate the expected P3b latency shift between predictive and non-predictive targets. These findings show that PFC patients are unable to utilize predictive local context to guide behaviour, providing evidence for a critical role of PFC in local contextual processing.
PMCID: PMC2768662  PMID: 19713281
context; prefrontal cortex; P3b; EEG; context positivity
9.  Specificity and Sensitivity of Claims-Based Algorithms for Identifying Members of Medicare+Choice Health Plans That Have Chronic Medical Conditions 
Health Services Research  2004;39(6 Pt 1):1839-1858.
To examine the effects of varying diagnostic and pharmaceutical criteria on the performance of claims-based algorithms for identifying beneficiaries with hypertension, heart failure, chronic lung disease, arthritis, glaucoma, and diabetes.
Study Setting
Secondary 1999–2000 data from two Medicare+Choice health plans.
Study Design
Retrospective analysis of algorithm specificity and sensitivity.
Data Collection
Physician, facility, and pharmacy claims data were extracted from electronic records for a sample of 3,633 continuously enrolled beneficiaries who responded to an independent survey that included questions about chronic diseases.
Principal Findings
Compared to an algorithm that required a single medical claim in a one-year period that listed the diagnosis, either requiring that the diagnosis be listed on two separate claims or that the diagnosis to be listed on one claim for a face-to-face encounter with a health care provider significantly increased specificity for the conditions studied by 0.03 to 0.11. Specificity of algorithms was significantly improved by 0.03 to 0.17 when both a medical claim with a diagnosis and a pharmacy claim for a medication commonly used to treat the condition were required. Sensitivity improved significantly by 0.01 to 0.20 when the algorithm relied on a medical claim with a diagnosis or a pharmacy claim, and by 0.05 to 0.17 when two years rather than one year of claims data were analyzed. Algorithms that had specificity more than 0.95 were found for all six conditions. Sensitivity above 0.90 was not achieved all conditions.
Varying claims criteria improved the performance of case-finding algorithms for six chronic conditions. Highly specific, and sometimes sensitive, algorithms for identifying members of health plans with several chronic conditions can be developed using claims data.
PMCID: PMC1361101  PMID: 15533190
Medical informatics; claim review; algorithms; specificity and sensitivity
10.  Impact of HMO Withdrawals on Vulnerable Medicare Beneficiaries 
Health Care Financing Review  2005;26(3):5-30.
The Medicare+Choice (M+C) program has faced successive waves of plan withdrawals since 1999. We collected data from 1,055 beneficiaries who were involuntarily disenrolled from a health maintenance organization (HMO) that withdrew from six large markets in 1999 to investigate how they were impacted by the forced change in coverage. Administrative data from this HMO were used to oversample beneficiaries who were perceived to be vulnerable based on their poor health status in the period before the HMO withdrawal. Although most beneficiaries dealt with the withdrawals without major problems, appreciable numbers of beneficiaries did report adverse impacts. These negative impacts were more likely to occur for low-education, low-income, minority beneficiaries. We found little evidence, however, that beneficiaries who were vulnerable due to their poorer health experienced more adverse effects.
PMCID: PMC4194939  PMID: 17290625

Results 1-10 (10)