Systemic comorbidities, seasonal onset, and antihypertensive medication use in primary angle-closure disease subtypes.

AIM: To investigate clinical characteristics, comorbidities, seasonal onset, and antihypertensive medication use among acute primary angle-closure (APAC), chronic primary angle-closure glaucoma (CPACG), and primary angle-closure suspect (PACS) patients. METHODS: A retrospective cross-sectional study of 484 Chinese patients was conducted. Baseline demographics, hypertension and diabetes prevalence, antihypertensive medication use, and seasonal onset patterns were compared across primary angle-closure disease (PACD) subtypes. Seasonal variation was assessed using the von Mises distribution, with subgroup analyses stratified by systemic conditions and medication use. RESULTS: CPACG patients were older (median 71 vs 67y in APAC, P<0.001) with higher hypertension (47.74% vs 31.16%, P=0.003) and diabetes prevalence (20.60% vs 10.05%, P=0.014). Multivariate analysis showed hypertension [odds ratio (OR)=1.85] and diabetes (OR=2.00) were significant predictors of CPACG vs APAC. A modest but significant seasonal peak of APAC onset was identified in early June. Subgroup analyses revealed significant shifts in seasonal patterns according to hypertension (P=0.023), diabetes (P<0.001), and calcium channel blocker (CCB) use (P=0.025). Angiotensin-converting enzyme inhibitors (ACEIs) use was absent in APAC patients but present in CPACG and PACS groups; CCB use was highest in APAC patients, though differences were not statistically significant. CONCLUSION: Vascular and metabolic comorbidities are more prevalent in CPACG than APAC, suggesting their role in CPACG pathogenesis. The early-summer peak in disease onset points to possible environmental triggers. Seasonal variation in APAC onset appears to be influenced by systemic vascular conditions and antihypertensive medication use, supporting a multifactorial interaction between environmental, systemic, and pharmacologic factors in APAC.