Trends in prevalence and outcomes of frailty in a Swiss university hospital: a retrospective observational study

Background: Frailty complicates management and worsens outcomes. We assessed the prevalence, determinants and consequences of frailty among elderly patients in a hospital setting. Design: Retrospective observational study in a Swiss university hospital. Methods: 22,323 patients aged >= 65 years hospitalized between January 2009 and December 2017 at the internal medicine ward were included. Frailty was defined by the Hospital Frailty Risk Score (HFRS) and patients were categorized as low (HFRS<5), intermediate (HFRS 5-15) and high (HFRS>15) risk. Results: Overall prevalence of intermediate and high risk of frailty was 43% and 20%, respectively; prevalence was higher in women and increased with age. Prevalence of high risk of frailty increased from 11.4% in 2009 to 31% in 2012, and decreased to 19.2% in 2017. After multivariable adjustment, frailty was associated with increased length of stay: average and (95% confidence interval) 11.9 (11.7-12.1), 15.6 (15.4-15.8) and 19.7 (19.3-20.1) days for low, intermediate and high risk, respectively, and increased likelihood of ICU stay: odds ratio (OR) and (95% CI) 1.57 (1.41-1.75) and 2.10 (1.82-2.42) for intermediate and high risk, respectively, p for trend <0.001. Frailty was associated with increased likelihood of hospital costs >70,000 CHF: OR and (95% CI) 3.46 (2.79-4.29) and 10.7 (8.47-13.6) for intermediate and high risk, respectively, p for trend <0.001, and with a lower likelihood of complete cost coverage: OR and (95% CI) 0.70 (0.65-0.76) and 0.52 (0.47-0.58) for intermediate and high risk, respectively, p for trend<0.001. Conclusions: Frailty is a frequent condition among hospitalized patients and is associated with higher costs.