Reduction in admissions of patients with acute primary angle closure occurring in conjunction with a rise in cataract surgery in Taiwan

Purpose: Using 8 year nationwide administrative data, this study sets out to investigate the relationship between the total number of cataract operations undertaken in Taiwan and admissions for acute primary angle closure (APAC). Methods: Monthly cataract surgery and APAC admission rates, per 100000 of the population, were provided by 1997-2004 inpatient and outpatient data obtained from the Taiwanese National Health Insurance Research Database. The 3814 cases of APAC and 503687 patients who had undergone cataract operations were categorized by age groups (40-49, 50-59, 60-69 and ≥70 years) and by gender. Spearman rank correlation coefficients were used to examine the direction and strength of the relationships. Results: Throughout the study period, the admissions for APAC showed a steady decline from 630 cases in 1997 to 351 cases in 2004, while the number of cataract operations revealed a gradual increase from 26600 in 1997 to 77924 in 2004. The Spearman rank correlation coefficients showed significant inverse relationships between monthly APAC admission rates and monthly cataract operation rates for the total group (r = -0.407, P < 0.001), males (r = -0.330, P < 0.001), females (r = -0.444, P < 0.001), 40-49year olds (r = -0.335, P < 0.001), 50-59year olds (r = -0.497, P < 0.001) and 60-69year olds (r = -0.417, P < 0.001). No significant inverse relationship was observed for the ≥70 age group. Conclusions: Significant inverse relationships were noted between the monthly APAC admission rates and the monthly cataract operation rates. We recommend that data should be collected from other regions and ethnic groups to determine the inter-relationships.