Cataract surgery is associated with a reduced risk of dementia: a nationwide population-based cohort study.

BACKGROUND AND PURPOSE

Our purpose was to determine the association of cataract surgery with subsequent development of dementia in older adults with newly diagnosed cataract.

METHODS

By using data from Taiwan National Health Insurance Research Database (NHIRD), a population-based cohort study including 491 226 subjects aged 70 or older with first-time diagnosis of cataract coded from 2000 to 2009 was conducted. After matching cataract patients receiving cataract surgery with cataract patients without receiving cataract surgery for age, sex, index date, Charlson Comorbidity Index score, interval between first coding of cataract diagnosis and index date, hypertension and diabetes mellitus, 113 123 patients in each cohort were enrolled. The main outcome measure was newly diagnosed dementia coded by neurologists or psychiatrists more than 365 days after cataract surgery. Incidence rate and hazard ratio of dementia were compared between the cataract surgery and cataract diagnosis cohorts.

RESULTS

The incidence rate of dementia was 22.40 per 1000 person-years in the cataract surgery cohort and 28.87 per 1000 person-years in the cataract diagnosis cohort. The rate of dementia was significantly lower in the cataract surgery group (hazard ratio 0.77, 95% confidence interval 0.75-0.79, P < 0.001). Female gender (P < 0.001) and a shorter interval between the date of first coding of a cataract diagnosis and the date of cataract surgery (P = 0.009) were significantly associated with a lower incidence rate of dementia.

CONCLUSION

In an NHIRD cohort of Taiwanese aged 70 years and older with a diagnosis of cataract, patients undergoing cataract surgery were associated with a reduced risk of subsequent dementia compared with those without cataract surgery.