Influence of age and sex on hospitalization of nursing home residents: A cross-sectional study from Germany

Background: Nursing homes residents (NHR) are frequently transferred to hospitals. There is some evidence that male NHR are more often hospitalized than females, but the influence of age is less clear and predictors might differ between sexes. Analyses according to age groups between males and females have only been investigated once and none of the existing studies have conducted multivariate analyses stratified by sex. Aim of this study was to fill this gap. Methods: We used data of the "Inappropriate Medication in patients with REnal insufficiency in Nursing homes" (IMREN) study, which was conducted between October 2014 and April 2015 in nursing homes in northwestern Germany (Bremen and Lower Saxony). Anonymised data was obtained by nursing staff of the participating nursing homes. All residents living in the participating care units were included. We assessed whether they were hospitalized at least once during the preceding 12 months. Cluster-adjusted multivariate logistic regression was applied to identify variables associated with hospitalizations. All analyses were stratified by sex. Results: Of 852 residents from 21 nursing homes (mean age 83.5 years; 76.5% females), 43.1% (95% confidence intervals [95% CI]: 35.6-50.5) were hospitalized at least once during the preceding 12 months. This proportion was higher in residents institutionalized within the last 6 months compared to those with a longer length of stay (65.7% vs. 39.5%). Although not statistically significant, males were more often hospitalized than females (52.4% vs. 40.3%) and differences between sexes are particularly remarkable for age, health status and length of stay. In females, the chance of being hospitalized decreased steadily with age (OR: 2.40 [95% CI: 1.24-4.64] and 1.60 [95% CI: 1.05-2.43] for age groups < 75 and 75-84 years compared to 85+ years). On the other hand, males aged 75-84 years had a statistically significant lower chance compared to 85+ years olds (OR: 0.41; 95% CI: 0.19-0.90). Conclusions: Differences in factors associated with hospitalizations might exist between sexes. We strongly suggest that further studies on hospitalizations of NHR should stratify their analyses by sex.