(P-003) Incidence Rates (IR) and IR Ratios of Alzheimer’s Disease in Patients with Cataract Compared to the General Population: Analyses Using the Clinical Practice Research Datalink (CPRD)

Background: Previous research suggests a link between cataract and Alzheimer’s disease (AD), as postulated by one observational study (Lai et al 2014).

Objectives: To analyse the incidence of AD in patients with or without cataract.

Methods: In the UK-based CPRD database, we identified incident AD patients in a cohort of patients with cataract (i.e., the exposure of interest), aged over 39 years, between 1995 and 2019, and in a random sample of the general population without cataract, matched for age, sex, GP and calendar time.
We assessed AD incidence rates (IRs) and incidence rate ratios (IRRs). We defined AD by diagnosis code plus one or more prescriptions (Rx) for anti-AD medication. We excluded individuals with a diagnosis of vascular or other dementias at any time in their patient record as well as patients with a recorded Rx for an anti-AD medication before cohort entry.
We assessed AD cases by age, sex, exposure, and year. We calculated person-time of exposure by adding up individual exposure times.

Results: In the main analysis, we included 403’564 patients with cataract and an equal number of cataract free individuals. During follow-up, we identified 5’932 cataract patients who developed AD and 5’944 AD cases in the comparison group. The crude IR of AD was 2.55 (95% CI 2.48-2.61) per 1’000 person-years (py) in patients with cataract, and 2.97 (2.89-3.04) per 1’000 py in the comparison group. The IRR was 0.86 (0.83-0.89). The IRR was similar in men and women as well as in individuals aged 40 to 79 years compared to those ≥80 years.

Conclusions: In contrast to a previous study, we did not observe an increased risk of AD in patients with cataract compared to the general population.