[Factors associated with hospitalization for ambulatory care sensitive conditions in municipalities]

To describe variability in admission rates for ambulatory care sensitive conditions (ASSC) in municipalities in the catchment area of a tertiary hospital and to determine the influence of primary care characteristics, socioeconomic factors, health of the population, and geographical accessibility to the hospital on this variability.

An ecological study was carried out in 34 municipalities in the area served by the Hospital Virgen de las Nieves in Granada (Spain) including all admissions for ASSC from 1997 to 1999. The admission rates for men and women were calculated separately and were age-standardized by the indirect method. The following factors were analyzed as independent variables: characteristics of primary care (type of healthcare model and type of center), socioeconomic factors (unemployment rate, income per capita, number of business establishments, size of municipality), health (mortality rate), and accessibility (time in minutes from the municipality to the hospital). A multiple lineal regression model was estimated.

A total of 9.8% of all hospital admissions were due to ASSC. The mean annual admission rate was 10 admissions per 1.000 inhabitants. This rate was higher for men and for persons aged more than 74 years. The standardized admission ratios were not statistically different from 1 in 56% of the municipalities and were higher than 1 in 26% and lower than 1 in 18%. Sixty-two percent of the variability in rates for men was associated with time taken to reach the hospital, size of municipality, the interaction between both variables, and mortality. Eighteen percent of the variability in rates for women was associated with time taken to reach the hospital and the unemployment rate.

Variability in admission rates for ASSC was not associated with primary care characteristics in the geographical area analyzed. Accessibility (measured as time to the hospital) was the only variable associated with higher rates in both men and women. Admission rates for ASSC among women were higher when unemployment rates were higher, and rates among men were higher in larger municipalities and in those with higher mortality.