Which Domain of Self-Rated Health Best Predicts Medical Care Utilization Among Taiwanese Adults?

BACKGROUND: We attempted to identify the domain of self-rated health (SRH) that best predicts medical care utilization among Taiwanese adults. In addition, we examined the association between SRH and different measure of medical care utilization. METHODS: We analyzed data on 11 987 community-dwelling adults aged 18 to 64 years from the 2005 Taiwan National Health Interview Survey (NHIS). NHIS data were linked to the 2006 National Health Insurance (NHI) administrative database. Then, medical care utilization in 2006, including all outpatient visits, hospitalizations, and mental health outpatient visits, was identified. Domain-specific health ratings were measured by using the Short Form-36 (SF-36) health survey questionnaire. Negative binominal models were used to estimate the contribution of the health domains to medical care utilization. Incidence rate ratios (IRRs) are presented. RESULTS: The IRR for the physical component scale showed that those with the highest scores had 77% of the outpatient visits of those with the lowest scores. The importance of mental health domains was markedly higher in estimating mental health outpatient visits. Those with mental health scores above the median had only 61% of mental health outpatient visits of those with scores below the median. CONCLUSIONS: A person’s medical care utilization is reflected in the different domains of general health. Domain-specific measures of subjective health are not interchangeable with global general health ratings, because different domains have independent effects on medical care utilization. Our results are potentially important for medical resource allocation because they identify different health domain experiences that require improvement.