Factors associated with hospitalization risk among community living middle aged and older persons: Results from the Swedish Adoption/Twin Study of Aging (SATSA)

The aims of the present study were to: (1) describe and compare individual characteristics of hospitalized and not hospitalized community living persons, and (2) to determine factors that are associated with hospitalization risk over time. We conducted a prospective study with a multifactorial approach based on the population-based longitudinal Swedish Adoption/Twin Study of Aging (SATSA). A total of 772 Swedes (mean age at baseline 69.7 years, range 46-103, 59.8% females) answered a postal questionnaire about physical and psychological health, personality and socioeconomic factors. During nine years of follow-up, information on hospitalizations and associated diagnoses were obtained from national registers. Results show that 484 persons (63%) had at least one hospital admission during the follow-up period. The most common causes of admission were cardiovascular diseases (25%) and tumors (22%). Cox proportional hazard regression models controlling for age, sex and dependency within twin pairs, showed that higher age (HR = 1.02, p < 0.001) and more support from relatives (HR = 1.09, p = 0.028) were associated with increased risk of hospitalization, while marital status (unmarried (HR = 0.75, p = 0.033) and widow/widower (HR = 0.69, p < 0.001)) and support from friends (HR = 0.93, p = 0.029) were associated with lower risk of hospitalization. Social factors were important for hospitalization risk even when medical factors were controlled for in the analyses. Number of diseases was not a risk in the final regression model. Hospitalization risk was also different for women and men and within different age groups. We believe that these results might be used in future interventions targeting health care utilization.