Risk and dose–response relationship of diabetes mellitus for endophthalmitis after cataract surgery in a nationwide cohort study in Taiwan

Background: To investigate the risk of endophthalmitis after cataract surgery in patients with diabetes mellitus (DM) and evaluate the dose–response relationship. Methods: This retrospective cohort study enrolled patients who underwent bilateral cataract surgeries from 2000 to 2017 in Taiwan National Health Insurance Research Database. The endophthalmitis rates within 3 months after cataract surgery were compared between DM and non-DM cohorts using a generalised estimating equation. The diabetes complications severity index (DSCI) score was adopted to assess the dose–response effect on the endophthalmitis rate. Results: A total of 883 398 patients (1 766 796 eyes) were included. Patients with DM had an increased risk of endophthalmitis after cataract surgery than patients without DM (0.261% vs. 0.242%, adjusted odds ratio = 1.09, 95% confidence interval = 1.03–1.16). The higher endophthalmitis rate in the DM group than in the non-DM group remains after excluding those with prior vitrectomy or intravitreal injection (IVI), and took IVI between the cataract surgery and endophthalmitis (p = 0.0156, 0.0048, and 0.0139). There was a significant dose–response relationship on the likelihood of endophthalmitis in DM patients when DCSI score >10. The endophthalmitis rate is highest among DM complications in patients with metabolic disorders (0.342%). Conclusion: DM was a risk factor for endophthalmitis after cataract surgery after adjusting for age, sex, common systemic disorders, and excluding those with prior vitrectomy or IVI and having IVI between cataract surgery and endophthalmitis. A dose–response relationship was noted in DM patients with a DCSI score >10.