Physician and hospital utilization among noninstitutionalized elderly adults: an analysis of the Health Interview Survey.

Data on 15,899 noninstitutionalized, elderly adults taken from the 1978 Health Interview Survey were used to assess the effects of the predisposing, enabling, and need characteristics on the volume of physician and hospital utilization. These were measured three ways: the actual number of visits (nights), and truncated and logarithmic transformations of that actual volume. Multiple regression analyses explain 3.9% to 21.3% of the variance in physician utilization and 5.1% to 9.4% of the variance in hospital utilization. The unique contributions of the need characteristics account for 56.8% to 66.7% of the variance explained in physician utilization and 74.5% to 77.7% of the variance explained in hospital utilization, suggesting an apparently equitable system is operative in elderly adults' use of health services. The effects of the three methods of coding physician and hospital utilization on the significance of the regression coefficients and the magnitude of the R2 values were examined and their implications are discussed.