Androgen Deprivation Therapy and the Risk of Newly Developed Dry Eye Syndrome in Patients with Prostate Cancer: A Nationwide Nested Case–Control Study in the Republic of Korea

<b>Background:</b> We aimed to evaluate the association between androgen deprivation therapy (ADT) and newly developed dry eye syndrome (DES) in patients with prostate cancer. <b>Methods:</b> A nested case-control study was conducted. From the nationwide claims database of the Republic of Korea, 125,005 patients were included in the final analysis. Cases were defined as those newly diagnosed with DES during follow-up, and 12,654 patients were identified. The cases were matched with controls in a ratio of 1:4. Odds ratios (ORs) for newly developed DES associated with ADT were estimated using conditional logistic regression. <b>Results:</b> After matching, 7499 cases and 29,996 controls were selected. ADT was associated with a reduced risk of newly developed DES in patients with prostate cancer compared to no ADT (OR = 0.875; 95% confidence interval, 0.825-0.927; <i>p</i> < 0.0001). An accumulated dose of ADT < 1 year was associated with a reduced risk of incidental DES (OR = 0.811; 95% CI, 0.751-0.875; <i>p</i> < 0.0001), and a duration of 1-2 years was also associated with a reduced risk (OR = 0.890; 95% CI, 0.802-0.986; <i>p</i> = 0.026). No association was observed with an ADT duration of ≥2 years. <b>Conclusions:</b> The use of ADT, especially for shorter durations (<2 years), was associated with a reduced risk of newly developed DES in S. Korean patients with prostate cancer.