Elizabeth Wasilevich

Association of daily asthma emergency department visits and hospital admissions with ambient air pollutants among the pediatric Medicaid population in Detroit: Time-series and time-stratified case-crossover analyses with threshold effects

BACKGROUND Asthma morbidity has been associated with ambient air pollutants in time-series and case-crossover studies. In such study designs, threshold effects of air pollutants on asthma outcomes have been relatively unexplored, which are of potential interest for exploring concentration-response relationships. METHODS This study analyzes daily data on the asthma morbidity experienced by the pediatric Medicaid population (ages 2-18 years) of Detroit, Michigan and concentrations of pollutants fine particles (PM2.5), CO, NO2 and SO2 for the 2004-2006 period, using both time-series and case-crossover designs. We use a simple, testable and readily implementable profile likelihood-based approach to estimate threshold parameters in both designs. RESULTS Evidence of significant increases in daily acute asthma events was found for SO2 and PM2.5, and a significant threshold effect was estimated for PM2.5 at 13 and 11 μg m(-3) using generalized additive models and conditional logistic regression models, respectively. Stronger effect sizes above the threshold were typically noted compared to standard linear relationship, e.g., in the time series analysis, an interquartile range increase (9.2 μg m(-3)) in PM2.5 (5-day-moving average) had a risk ratio of 1.030 (95% CI: 1.001, 1.061) in the generalized additive models, and 1.066 (95% CI: 1.031, 1.102) in the threshold generalized additive models. The corresponding estimates for the case-crossover design were 1.039 (95% CI: 1.013, 1.066) in the conditional logistic regression, and 1.054 (95% CI: 1.023, 1.086) in the threshold conditional logistic regression. CONCLUSION This study indicates that the associations of SO2 and PM2.5 concentrations with asthma emergency department visits and hospitalizations, as well as the estimated PM2.5 threshold were fairly consistent across time-series and case-crossover analyses, and suggests that effect estimates based on linear models (without thresholds) may underestimate the true risk.

Pediatric asthma surveillance using Medicaid claims.

Objective. The purpose of this study was to describe the prevalence of asthma among children using alternative case definitions applied to administrative claims data, and to assess year-to-year classification concordance. Methods. This study was a retrospective cohort analysis of 357,729 children 0–18 years using 2001–2002 Michigan Medicaid claims. Asthma cases were classified using six alternative definitions based on outpatient, emergency department, inpatient, and pharmacy claims for asthma, including the Health Plan Employer Data Information Set (HEDIS) persistent asthma criteria commonly used for assessments of asthma health care quality: at least one asthma inpatient admission or emergency department visit, four or more asthma medications events, or four asthma outpatient visits and two asthma medication events. Results. Overall, asthma prevalence varied widely between alternative case definitions, ranging from 14.9% based on claims evidence of any type of asthma utilization to 3.7% when restricted to those with four or more asthma medication dispensing events. Among cases meeting HEDIS persistent asthma criteria in 2001, 55.5% met these criteria in 2002. Those with four or more asthma medication dispensing events had the best overall classification concordance between 2001 and 2002. Utilization of asthma services and prevalence estimates were highest among children younger than 5 years old, but year-to-year classification concordance was poorest among these cases (p<0.0001), irrespective of case definition. Conclusions. While overall asthma prevalence may remain relatively stable from year to year, individuals may not be classified consistently as cases over time, regardless of case definition. Studies that identify asthma cases in one year and assess asthma outcomes in a subsequent year may introduce substantial bias as a result of case misclassification. Among the case definitions considered in this study, our findings suggest that this bias is minimized among cases classified using the four or more asthma medication dispensing events criterion.

Asthma exacerbation and proximity of residence to major roads: a population-based matched case-control study among the pediatric Medicaid population in Detroit, Michigan

BackgroundThe relationship between asthma and traffic-related pollutants has received considerable attention. The use of individual-level exposure measures, such as residence location or proximity to emission sources, may avoid ecological biases.MethodThis study focused on the pediatric Medicaid population in Detroit, MI, a high-risk population for asthma-related events. A population-based matched case-control analysis was used to investigate associations between acute asthma outcomes and proximity of residence to major roads, including freeways. Asthma cases were identified as all children who made at least one asthma claim, including inpatient and emergency department visits, during the three-year study period, 2004-06. Individually matched controls were randomly selected from the rest of the Medicaid population on the basis of non-respiratory related illness. We used conditional logistic regression with distance as both categorical and continuous variables, and examined non-linear relationships with distance using polynomial splines. The conditional logistic regression models were then extended by considering multiple asthma states (based on the frequency of acute asthma outcomes) using polychotomous conditional logistic regression.ResultsAsthma events were associated with proximity to primary roads with an odds ratio of 0.97 (95% CI: 0.94, 0.99) for a 1 km increase in distance using conditional logistic regression, implying that asthma events are less likely as the distance between the residence and a primary road increases. Similar relationships and effect sizes were found using polychotomous conditional logistic regression. Another plausible exposure metric, a reduced form response surface model that represents atmospheric dispersion of pollutants from roads, was not associated under that exposure model.ConclusionsThere is moderately strong evidence of elevated risk of asthma close to major roads based on the results obtained in this population-based matched case-control study.

Barriers and Facilitators for Utilization of Genetic Counseling and Risk Assessment Services in Young Female Breast Cancer Survivors

Introduction. Women diagnosed with breast cancer at a young age are more likely to carry a cancer predisposing genetic mutation. Per the current NCCN recommendations, women diagnosed under age 50 should be referred to cancer genetic counseling for further risk evaluation. This study seeks to assess patient-reported barriers and facilitators to receiving genetic counseling and risk assessment among a community-based population of young breast cancer survivors (YBCS). Methods. Through the Michigan Cancer Surveillance Program, a state-based cancer registry, 488 women diagnosed with breast cancer before age 50 in 2006-2007 were identified. They received a mail survey regarding family history and facilitators and barriers to receiving genetic counseling and risk assessment. Results. Responses were received from 289 women (59.2%). One hundred twenty-two (42.2%) reported having received cancer genetic counseling. The most frequent reason identified for receiving services was to benefit their familys future. The top reasons for not attending were “no one recommended it” and “medical insurance coverage issues.” Discussion. This study is the first published report using a state cancer registry to determine facilitators and barriers to receiving genetic counseling and risk assessment among YBCS. These findings demonstrate the need for additional awareness and education about appropriate indications for genetic services.

An Examination of EPPM Predictions When Threat Is Perceived Externally: An Asthma Intervention With School Workers

Little research informs the use of the Extended Parallel Process Model (EPPM) of persuasion when threat and efficacy judgments are rendered for someone other than the message recipient. Nevertheless, a wide range of health promotion consists of influencing such judgments. Two studies examine the utility of using the EPPM in a context involving threats to others. Results show that the expected measurement models hold in this new context, and that an additive model is a stronger fit than a multiplicative one when considering how threat and efficacy combine to affect behavioral intentions but not when considering behavior. The study also examines the effects of a print intervention implemented with school employees in Michigan derived from the EPPM. The results are discussed in terms of their theoretical import and their application in this new context.

Prevalence of work-related asthma in Michigan, Minnesota, and Oregon.

Introduction. Adults who have asthma that is caused or aggravated by triggers at work experience a reduced quality of life. In this study, the authors sought to estimate the proportion of asthma that is associated with work using a state-based survey of adults with asthma. Methods. In 2005, Michigan, Minnesota, and Oregon piloted the Behavioral Risk Factor Surveillance System Adult Asthma Call-Back Survey, with sample sizes of 867, 469, and 1072, respectively. Six questions addressing work-related asthma (WRA) were analyzed to generate estimates of the proportion of adult asthma that is work-related and compare those with and without WRA. Results. Over half of all adults with asthma (53%) reported that their asthma was caused or made worse by any job they ever had, and among these respondents reporting WRA, only 21.5% to 25.1% reported ever telling or being told by a health professional that their asthma was work-related. Additionally, adults with WRA consistently reported poorer asthma control and higher health care utilization than adults with non-WRA. Conclusions. WRA is a common but frequently unrecognized health problem, and this lack of recognition might contribute to poorer asthma control among adults with WRA. Because early recognition, treatment, and management of WRA are crucial for improving long-term prognosis, clinicians need to include assessment of workplace triggers in both their diagnostic and treatment plans for adult patients with asthma.

Short-term Outdoor Temperature Change and Emergency Department Visits for Asthma Among Children: A Case-Crossover Study

Although weather changes are known to cause asthma symptoms, their impact on asthma-related health-care utilization is poorly understood. The objective of the present study was to determine the association between short-term outdoor temperature change and asthma-related emergency department (ED) visits among children 3-18 years of age in Detroit, Michigan, in 2000-2001. Descriptive analyses of patient and ED visit characteristics were performed. A case-crossover study utilizing time-stratified controls was conducted to determine the impact of maximum temperature change and change rate measured during 4-, 8-, 12-, and 24-hour periods. Multivariable conditional logistic regression demonstrated the relation between ED visits and temperature change after controlling for other weather and pollutant measures. There were 4,804 asthma-related ED visits during the study period, and they occurred most frequently in the fall and during morning hours. The case-crossover study showed a statistically significant inverse relation between ED visits and maximum 24-hour temperature change after adjustment for climatic factors (for temperature change, odds ratio = 0.992, P = 0.04; for temperature change rate, odds ratio 0.972, P = 0.01). The association persisted after air pollutant measures were added to the model, although the association was not significant. Despite the finding that a greater 24-hour temperature change decreased the risk of asthma-related ED visits, the overall results suggested a negligible association with short-term temperature change.

Asthma surveillance using medicaid administrative data: A call for a national framework

Connecticut, Michigan, and New York have successfully used Medicaid administrative data to conduct surveillance of asthma prevalence, related health service utilization and costs, and quality of asthma care. Since these assessments utilize beneficiary-level data, a wide range of population-based summaries is feasible. Opportunities exist to build upon the collective experiences of these three states to establish a national framework for asthma surveillance using Medicaid administrative data. This framework could be designed to respond to each states unique data considerations and asthma management priorities, while establishing standardized criteria to enhance the comparability of asthma surveillance data among states. Importantly, a common asthma case definition using comparable methods is necessary to enable comparisons of prevalence estimates between states. Case definitions that could serve as the foundation for such a framework are presented. Mechanisms to foster sharing of methodologies and experiences will be instrumental for broad implementation across states. This collaboration will be of increasing importance as states experience mounting financial pressures due to increasing Medicaid enrollment and dwindling resources.

Using Billing Data to Describe Patterns in Asthma-Related Emergency Department Visits in Children

OBJECTIVES. To describe the development and evaluation of a pilot emergency department (ED)-based asthma surveillance system for childhood asthma visits based on billing data and to illustrate how the data can be used to document trends and patterns in ED visits for asthma in children. METHODS. During 2001 and 2002, aggregate reports based on ED billing data from 3 hospitals in western Michigan were obtained from a single physician billing company. Data were tabulated and graphed to show trends in the monthly number of ED visits for asthma in children. Comparisons were made by age, gender, and site. We evaluated the system by using established guidelines. RESULTS. The data illustrated strong seasonal trends, as well as marked differences in ED use according to age and gender. The total numbers of asthma ED visits were remarkably similar between the 2 years evaluated; however, the timing and duration of the seasonal peaks differed. Our evaluation of the system found that it met many of the characteristics that define successful surveillance systems, including simplicity, flexibility, acceptability, sensitivity and positive predictive value, timeliness, and stability. However, the surveillance systems representativeness was limited by the inability to calculate valid population-based ED-visit rates. Despite this limitation, the data provided useful information by documenting the burden and demographic profile of children who use the ED for asthma care and in identifying seasonal and time-related trends. CONCLUSIONS. We were able to successfully implement a pilot ED-based surveillance system for childhood asthma visits by using billing data. This system promotes the understanding of the burden of asthma among children visiting the ED. The development of an ED-based surveillance system for childhood asthma visits using billing data is recommended, particularly when there is a desire to understand the characteristics of children with asthma who use the ED and/or a need to understand the impact of local asthma quality-improvement programs.

Investigating asthma deaths among children and young adults: Michigan asthma mortality review

Objective. We developed a surveillance system to investigate asthma deaths in children and young adults. Methods. A rapid asthma death notification and investigation system for Michigan was developed to identify interventions to prevent future deaths among people aged 2–34 years. Multidisciplinary panels to determine causal factors and recommend preventative actions reviewed information from death certificates, autopsies, next-of-kin interviews, and medical records. An annual report was disseminated to public health workers, health-care providers, insurers, and others. Results. Eighty-six asthma deaths in Michigan residents, aged 2–34, occurred from 2002–2004. Sixty-one next of kin were interviewed and medical records were obtained for 84 of the deceased. Summaries were prepared on each of the deceased and were reviewed by expert panels, which reached consensus on causal factors and potential preventive action for each death. Each year an annual report, which summarized the causal factors and potential preventive activity, was prepared. Conclusion. This review has informed and catalyzed interventions to improve asthma care and management in Michigan. Factors leading to the reviews success and future activities are discussed.