Associations between physician supply levels and amenable mortality rates: A descriptive and panel data analysis of Taiwan over nearly four decades

Background. Access to health care is an important determinant of health, but despite years of research, it remains unclear whether having more physicians reduces mortality. In this study, we investigate whether a greater supply of physicians in given administrative areas is associated with lowers rates of amenable mortality, defined as deaths that can be delayed with appropriate and timely medical treatment or public health measures.Methods. We use Taiwan’s population-level National Death Certification Registry data spanning nearly four decades to study the trend in age-standardized amenable mortality rates by area physician supply quartiles. We also conducted multivariate panel data regression analyses of the association between age-standardized amenable mortality rates and physician supply, controlling for mean household income, education attainment, urbanization levels, decade fixed effects, and the implementation of universal health care.Results. The trend analyses (adjusted for age and sex only) show that Taiwanese townships in the top quartile of physician supply consistently had the lowest age-standardized amenable mortality rates. However, in the panel data regression analyses, after controlling for at least mean household income, the negative association between physician supply and overall amenable mortality loses statistical significance, although it remains statistically significant for ischemic heart disease.Conclusions. These findings suggest that physician supply, while important, is but one input that contributes to population health and is likely confounded with other socioeconomic factors correlated with better health. Physician supply levels are not randomly distributed, and doctors likely choose to practice in higher income areas and areas with demonstrated medical need. More research is needed, but policy makers should consider broader social policies, not just healthcare resources, as means to promote population health once a critical mass of physicians is achieved.