Does universal comprehensive insurance encourage unnecessary use? Evidence from Manitoba says "no".

BACKGROUND: Many argue that "free" medical care leads to unnecessary use of health resources. Evidence suggests that user fees do discourage physician use, at least by those of low socioeconomic status. In this study, we compare health care utilization and health among socioeconomic groups to determine whether people of low socioeconomic status see physicians more than would be expected given their health status.
METHODS: We examined the use of health care services (physicians and hospitals) by residents of Winnipeg, Manitoba, in 1999. The cost of physician services was drawn directly from the claims filed, and the cost of hospital services was estimated using the Case Mix Group and Day Procedure Group methods linked to resource intensity weights and Manitoba hospital costs. We used neighbourhood indicators of socioeconomic status from the 1996 census and measured health status by examining rates of premature mortality, acute myocardial infarction, hip fracture (1995-1999) and diabetes (1999). Using these measures, we compared health status and health care use of residents living in areas with low average household incomes with those living in areas with high average household incomes. All rates were age- and sex-adjusted across the groups.
RESULTS: The province spent 44% more providing hospital and physician services to residents of Winnipeg neighbourhoods with the lowest household incomes (820 dollars/person annually v. 596 dollars/person for residents of the neighbourhoods with highest household incomes). However, expenditures were strongly related to health status. The 70% of the population on which the province spends 10% of its health care dollars scored well on all health indicators, and the 10% of the population on which 74% of the dollars are spent scored poorly. In each expenditure group, those with lower socioeconomic status had poorer health. In the highest expenditure group, those with lowest socioeconomic status had 82% higher premature mortality rates (23.0 v. 12.6 per 100,000 population) and 53% higher hip fracture rates (5.5 v. 3.6 per 100,000 population) than those with the highest socioeconomic status. Despite their poorer health, in each expenditure group, residents of the neighbourhoods with the lowest household incomes incurred physician expenditures that were similar to those of residents of wealthier neighbourhoods.
INTERPRETATION: Most people use little health care; high-cost users are a small group of very sick people drawn from all neighbourhoods and all income groups. People living in areas with low average household incomes use fewer physician services than might be expected, despite their poor health status.