[Differences in inpatient medical costs for the aged within one prefecture].
The rapid increase in the proportion of the elderly population has made the problem of medical costs increasingly important. This problem, however, is not uniform over all regions in Japan. In order to determine what factors are associated with per capita medical care expenditure of inpatients aged 70 years and over, in fiscal 1991, correlation analyses were performed using several indices of medical services, socioeconomic factors and medical supplies among 208 municipalities in one prefecture. Data from a survey in 1992 conducted by the Ministry of Health and Welfare was used in the analysis. Requests were sent to all 218 municipalities in one prefecture, and 208 responses were received a response rate of 95.4%. The main findings were as follows: 1) There were large differences in per capita medical care expenditure for those aged 70 years and over among the secondary medical areas in the prefecture. 2) Both the inpatient expenditures per person per year and bed-days in hospitals per person per year were positively correlated with number of hospital beds per 1,000, the aging population rate and death rate of those aged 70 years and over; but correlated negatively with the primary industry population rate for both sexes. 3) Inpatient expenditure per person per day was negatively correlated with the aging population rate, especially for men. 4) Three major factors that correlated significantly and positively with per capita medical care expenditure for those aged 70 years and over were bed days of inpatients per receipt, the total receipts per inpatient per year, and the number of the admission days of inpatients per year. These three major factors were negatively correlated but not significantly, with the per capita medical care expenditure per day. 5) Multiple regression analyses indicate that the aging population rate, the number of hospital beds per 1,000 of those aged 70 years and over, and death rate of those aged 70 years and over were independently correlated with the inpatient expenditure per person per year for both sexes. 6) Results of this analysis indicate that data from secondary medical regions within the prefecture rather than the municipalities yield a stronger possibility of clarifying those factors contributing to differences in per capita medical care expenditure.