[The structural analysis of inpatient medical cost of the aged in 81 secondary medical areas of 12 Prefectures in Japan].

In order to understand the structure of the per capita medical care expenditure of inpatients aged 70 years and over, correlational and principal component analyses were performed using several medical cost indices for fiscal 1991 in 81 secondary medical areas of 12 prefectures. Requests were sent to all of 777 municipalities in the 12 prefectures, and there were 763 responses for the response rate of 98.2%. A total of 1,647,187 residents who had been inpatients based on receipts for inpatient medical care expenditure were surveyed. There were 389,456 who responded that they had been inpatients at least once in the preceding 12 months, in 1991. The main results were as follows: 1) Of the residents aged 70 and over, 32.0% of men and 29.7% of women surveyed had at least one episode of hospital admission in the preceding 12 months in 1991. 2) Large differences in the medical care expenditure per inpatient per year for those aged 70 years and over exist in the secondary medical areas in 12 prefectures. 3) In both sexes, per capita expenditures for inpatient care per year are positively correlated with the bed-days in hospitals per inpatient per year, the bed days per receipt, the medical care expenditure per receipt, and the number of receipts per inpatient per year. On the other hand, for women it is negatively correlated with per capita medical care expenditure per day, but it is not statistically significant. 4) The medical care expenditure per inpatient per day is significantly negatively correlated with bed-days in hospital per receipt, the number of receipts per inpatient per year, bed-days in hospital per inpatient per year for both sexes. On the other hand, it is significantly positively correlated with medical care expenditure per receipt for both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)