Epidemiology and health services: year in review

PURPOSE OF REVIEW: Epidemiology began as the study of the occurrence of disease in populations. Initial studies focused on the presence of diseases by person, place, and time to identify risk factors for disease. The field has grown to include many subfields recognizing the contributions of multiple factors to disease susceptibility. RECENT FINDINGS: This review will focus on articles published October 2005-November 2006 relevant to genetic epidemiology, pharmacoepidemiology, and social determinants of health and health disparities. SUMMARY: Genetic epidemiology is the study of genetic contributions to disease occurrence, and of population-based genetic risks for disease. Genetics influences not only susceptibility to disease, but also the phenotype and severity of disease. Pharmacoepidemiology examines the outcomes of medication use, including clinical benefits and adverse effects. Gene-environment interactions are also included in this area. Typical topics in pharmacoepidemiology include studies of medication use, risks, benefits and genetic factors influencing the metabolism of medications. Social epidemiology is the study of social determinants of health, including psychosocial behaviors, socioeconomic status, interactions of individuals, the collective health of the community in which a person lives, and the position of the individual within society. Social epidemiology is directly relevant to studies of socioeconomic and ethnic disparities.     

State-of-the-art methodologies in alcohol-related health services research

Many of the failures to replicate clinical findings of treatment efficacy in more realistic field and community settings can be attributed to inappropriate research designs and other methodological shortcomings. In order to increase research designers' awareness of existing methodologies that may be better suited to answer the critical questions inherent in health services research on alcohol-related issues, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) convened an expert conference with three specific goals: (1) to identify the critical issues involved in alcohol services research; (2) to develop a primer that explicated each key area; and (3) to compile the resulting primers into an accessible resource for researchers, policy makers and consumers. The 9 papers in this special supplement are the product of that conference and are organized broadly around three phases of the research process: study design and implementation, data collection and use, and the analysis and interpretation of data. A final summary paper discusses the issues and offers a synthesis of key themes as well as some direction for the future.     

Hypertension and outcomes research From clinical trials to clinical epidemiology

Outcomes research seeks to identify effective evidence-based methods of providing the best medical care. While randomized clinical trials (RCT) usually provide the clearest answers, they are often not done or not practicable. More than a decade after the introduction of calcium channel blockers and angiotensin converting enzyme (ACE) inhibitors, clinical trial data about their effect on major disease endpoints in patients with hypertension are still not available. The primary alternatives are the use of randomized trials that include surrogate endpoints, such as level of blood pressure or extent of carotid atherosclerosis, and the use of observational studies that include major disease endpoints. Both approaches, their strengths and limitations, are discussed in detail. The possibility of residual confounding limits the strength of inferences that can be drawn from observational studies. Similarly, the possibility of important drug effects, other than those involving the surrogate endpoint, limits the inferences that can be drawn from randomized trials that rely solely on surrogate outcomes as guides to therapy. In the absence of evidence from large clinical trials that include major disease endpoints, treatment decisions and guidelines need to synthesize the best available information from a variety of sources. Consistency of findings across various study designs, outcomes, and populations is critical to the practice of evidence-based medicine and the effort to maximize the health benefits of antihypertensive therapies.     

The influence of race on health status outcomes one year after an acute coronary syndrome.

OBJECTIVES: The goal of this study was to compare health status (symptoms, function, and quality of life) outcomes of whites and blacks one year after an acute coronary syndrome (ACS). BACKGROUND: Although racial differences in the use of angiography and revascularization after ACS are known to exist, differences in health status outcomes have not been described. METHODS: We conducted a prospective registry of 1,159 consecutive ACS patients treated between February 1, 2000 and October 31, 2001. One-year health status was quantified with the Seattle Angina Questionnaire (SAQ) and Short Form-12 Physical Component Score (SF-12 PCS). Multivariable models were used to adjust for racial differences in sociodemographic, clinical, and treatment characteristics. RESULTS: Mortality rates were similar among the 196 black and 963 white patients (7.1% vs. 7.0%, p = 0.93); 81 died during follow-up, and 199 (17%) could not be interviewed. At one year, blacks had a higher prevalence of angina (43.4% vs. 27.1%), worse quality of life (SAQ score = 70.6 +/- 28.3 vs. 83.9 +/- 20.8), and poorer physical function (SF-12 PCS = 36.8 +/- 12.3 vs. 43.2 +/- 11.4; p < 0.0001 for all). Multivariable models, including hospital treatments, revealed a trend for more angina (odds ratio 1.46 [95% confidence interval 0.91 to 2.34]) and significantly worse quality of life (mean difference = -7.7 +/- 2.4, p = 0.002) and physical function (-3.6 +/- 1.3, p = 0.005). CONCLUSIONS: Blacks have more angina, worse quality of life, and worse physical function one year after an ACS than do whites. Closer surveillance of black ACS patients is needed to determine whether additional treatment can improve their outcomes.