Monthly variations and climatic factors on acute primary angle-closure admissions: a 5-year retrospective hospital-based study in Shenzhen, China

To investigate the monthly distribution of acute primary angle-closure (APAC) admissions in a specialized hospital in Shenzhen and its association with climatic factors.

A 5-year retrospective study of APAC inpatients from 2017 to 2021 at Shenzhen Eye Hospital were conducted. The medical records were retrieved and climate information was obtained from the government website. The monthly APAC admissions and evaluated the correlation with climatic factors were compared, including precipitation, air pressure, temperature, sunshine duration, humidity, and evaporation.

The overall mean age of 997 APAC inpatients was 64.63±9.89y, with females predominating (72.12%) and exhibiting significantly shorter axial lengths than males (22.26±0.89 vs 22.87±0.87 mm, P<0.001). APAC admissions peaked in May, especially for males ≤65y. Significant positive correlations were identified between admissions and humidity (r=0.498, P<0.01) as well as precipitation (r=0.306, P<0.05), while evaporation correlated negatively (r=-0.333, P<0.05). Males exhibited elevated APAC risk under high humidity [odds ratio (OR)=2.76, P=0.038], while increased air pressure (OR=0.12; 95%CI: 0.07–0.19), higher temperature (OR=0.22; 95%CI: 0.15–0.31), and greater evaporation (OR=0.92; 95%CI: 0.90–0.94) each exerted protective effects against such humidity-associated risk (all P<0.001).

Elevated relative humidity in May is the primary climatic driver, significantly increasing the risk of APAC attack in males ≤65y. However, these correlations are not significant in female, suggesting the possibility of an associated confounding factor.