ASSESSING THE HEALTH OF THE NATION - THE PREDICTIVE-VALIDITY OF A PREFERENCE-BASED MEASURE AND SELF-RATED HEALTH

Health-related quality-of-life (HRQOL) measures are becoming increasin gly important for evaluating the effectiveness of medical intervention s and assessing the health of populations. Preference-based instrument s, a subset of HRQOL measures, allow comparisons of overall health sta tus in populations and in clinical settings, and are suitable for econ omic analyses; but validity studies have used selected samples, mostly examining morbidity. This study compared the performance of a prefere nce-based instrument with self-rated health in predicting subsequent s elf-rated health, hospitalization, and mortality in a national cohort. A version of the Health Utility Index (HUI), constructed from questio ns in the 1982 to 1984 National Health and Examination Survey I Epidem iologic Follow-up Study (NHEFS), was used to develop scores for the 19 82 to 1984 survey sample. The relationship between both the NHEFS-HUI and self-rated health in 1982 to 1984, and subsequent decline in self- rated health, hospitalizations, and mortality experienced by 1987 were examined using survival analyses. The analyses adjusted for sociodemo graphic variables (age, sex, race, education, and income), medical con ditions, and smoking status reported at the 1982 to 1984 NHEFS intervi ew. Results indicated that NHEFS-HUI and self-rated health scores were worse in older persons, persons with one or more medical conditions, African Americans and those with less education and lower incomes. The effects of all 19 chronic conditions and smoking were reflected in lo wer self-rated health scores, whereas the NHEFS-HUI did not capture th e effects of two of the conditions or smoking status. Both measures ma de independent contributions to predicting hospitalizations and mortal ity by 1987; in addition, the NHEFS-HUI predicted decline in subsequen t self-rated health. The NHEFS-HUI also predicted health outcomes in t he subgroup of those in initial excellent or very good self-rated heal th. A preference-based instrument demonstrated predictive validity in three relevant domains of health status outcomes across all sociodemog raphic groups examined in this cohort. Self-rated health was better ab le to capture concurrent decrements in health associated with certain chronic illnesses and smoking. It is concluded that preference-based m easures capturing both functional status and health perceptions should be incorporated explicitly into national surveys to assess the health of populations.