Alzheimer's disease and related syndromes and hospitalization: a nationwide 5-year longitudinal study

To study the association between Alzheimer's disease and related syndromes (ADRS) and the incidence of short-stay hospitalizations from the year before (Y_-1 ) to 4 years after (Y₁ -Y₄ ) ADRS identification in the healthcare system.

Among all beneficiaries of the French health insurance general scheme aged 40 years or more, those with an incident ADRS in 2011, identified through long-term disease registry, hospitalization diagnoses or ADRS-specific drug delivery, were matched with beneficiaries without ADRS of the same age, gender and residence area. The annual incidence rates of all-cause hospitalizations (excluding those with a diagnosis code of ADRS) were compared between individuals with or without ADRS using incidence ratios (IRs) globally and by age, gender, deprivation index and modified Charlson score. We also studied cause-specific hospitalizations using patients' diagnoses and procedure codes.

A total of 90 871 subjects with and 90 871 subjects without ADRS were included (mean age 79.6 years, 66% females). From Y_-1 to Y₄ , incidence rates were significantly higher in subjects with ADRS than in those without for all-cause hospitalization [IR(Y_-1 ) = 1.73; 95% confidence intervals, 1.71-1.75; IR(Y₄ ) = 1.37; 95% confidence intervals, 1.35-1.39], hospitalizations for social reasons [IR(Y_-1 ) = 4.28; IR(Y₄ ) = 2.70], fall [IR(Y_-1 ) = 5.36; IR(Y₄ ) = 2.59], injury [IR(Y_-1 ) = 2.71; IR(Y₄ ) = 2.09] and infection [IR(Y_-1 ) = 2.04; IR(Y₄ ) = 2.07]. The inverse was observed for hospitalizations for cataract surgery [IR(Y_-1 )=0.73; IR(Y₄ ) = 0.51] or total hip prosthesis after 2 years [IR(Y₄ ) = 0.72].

Incident ADRS cases were associated with a higher incidence of hospitalization, but these subjects underwent some common non-emergency surgeries less frequently. Future studies need to assess the clinical impact of these differences.