Length of hospital stay after hip fracture and readmission rates of persons with and without Alzheimer's disease: a matched cohort study

Background Hospital length of stays (LOS) for incident of hip fracture are decreasing, but it is unknown if these changes have negative impacts on vulnerable older patient populations, like those with Alzheimer's disease (AD). We aimed to assess if persons with and without AD have different hospital LOS for hip fracture, and is the LOS associated with hospital readmissions. Methods Utilizing register-based data for a matched cohort study nested in the Medication use and Alzheimer's disease study (MEDALZ), we collected all community-dwelling persons in Finland diagnosed with AD during 2005-2012, had incident of first hip fracture between 2005 and 2015 after AD diagnosis, and were discharged alive from an acute care hospital. Hospital LOS and hospital readmissions within 30-days and 90-days were compared between those with and without AD and risk of readmission was assessed using binary logistic regression analysis. Results In this matched cohort study of 12,532 persons (mean age 84.6 years (95% CI: 84.5-84.7), 76.8% women), the median LOS in an acute care hospital was 1 day shorter for those with AD (median 4 days, IQR 3-7) than those without AD (median 5 days, IQR 3-7) (P < 0.001). However, the AD cohort had respectively 6 days and 5 days longer median LOS in a community hospital, and total hospital stay compared to the non-AD cohort (P < 0.001 for all comparisons). Those with AD had fewer readmissions within 30-days (10.7%) and 90-days (16.9%) compared to those without AD (13.3% 30-days and 20.7% 90-days) (P < 0.001 for all comparisons). Both cohorts had a reduced readmission risk within 30-days when the LOS in an acute care hospital was 4-14 days, compared to a LOS less than 4 days. Conclusions Persons with AD had shorter acute care hospital LOS, but had longer LOS in a community hospital setting compared to those without AD, which is similar to other findings when comparing total hospital LOS. These findings imply that short LOS in acute care hospitals may be associated with poor health outcomes for vulnerable older populations after hip fracture.