The relationship between physician supply, cardiovascular health service use and cardiac disease burden in Ontario: supply-need mismatch

Background — While health service use appears to be positively correlated with resource availability, no study has explored the interactions among health service supply, cardiovascular disease burden and health service use. The objective of the present study was to examine the relationship among cardiovascular evaluation and management intensity, physician supply and cardiovascular disease burden in the Canadian population.

Methods — The present cross-sectional, population-based study consisted of adult residents in Ontario in 2001. Cardiac evaluation and management intensity, the main outcome measure, was measured at the individual level, and consisted of receiving one or more of the following services: noninvasive cardiac testing, coronary angiography and statin use (the latter among individuals 65 years of age and older). Mortality was the secondary outcome measure. Cardiovascular disease burden, and cardiologist and primary care physician supply were measured at the regional (ie, county) level. Analyses were adjusted for age and sex using Poisson regression, accounting for regional clustering.

Results — Regional per capita cardiologist supply varied more than twofold across regions, but was inversely related to the regional cardiovascular disease burden (r=-0.34, P=0.01). Primary care physician supply was relatively evenly distributed across regions. Residents in areas with more cardiologists were more likely to receive some form of cardiac intervention (RR=1.074, 95% CI 1.066 to 1.082 per additional cardiologist per 100,000). Those in areas with more primary care physicians were also more likely to receive noninvasive cardiac testing (RR=1.056, 95% CI 1.051 to 1.061 per six additional primary care physicians per 100,000). However, the intensity of provision of cardiac health services was unrelated to regional cardiovascular disease burden and was not associated with improved survival.

Conclusions — The mismatch between physician supply and cardiac disease burden may explain why cardiovascular health service use is neither concordant with the cardiovascular disease burden nor associated with mortality in the population. These results underscore the importance of physician service maldistribution and supply-sensitive care on the appropriateness of cardiac health service use.