Association of glaucoma with 10-year mortality in a population-based longitudinal study in urban Southern China: the Liwan Eye Study

OBJECTIVES: To investigate the association between glaucoma and 10-year mortality rate in an adult population in China. DESIGN: Population-based cohort study. SETTING: The Liwan Eye Study, China. PARTICIPANTS: 1405 baseline participants aged 50 years and older were invited to attend a 10-year follow-up examination. PRIMARY AND SECONDARY OUTCOME MEASURES: The International Society of Geographic and Epidemiologic Ophthalmology criteria was used to define glaucoma. Detailed information of mortality was confirmed using the Chinese Centre for Disease Control and Prevention. Presenting visual impairment (PVI) was defined as a presenting visual acuity of less than 20/40 in the better-seeing eye. The 10-year mortality rates were compared using the log-rank test. Cox proportional hazards regression models were used to investigate the association between glaucoma and mortality. RESULTS: A total of 1372 (97.7%) participants with available gonioscopic data were included in the analysis. Of these, 136 (9.9%), 33 (2.4%) and 21 (1.5%) participants had primary angle closure (PAC) suspect (PACS), PAC and PAC glaucoma (PACG), and 29 (2.1%) had primary open angle glaucoma (POAG). After 10 years, 306 (22.3%) participants were deceased. The 10-year mortality was significantly associated with PACG (HR, 2.15, 95% CI 1.14 to 4.04, p=0.018) but not associated with PAC (HR, 1.27, 95% CI 0.67 to 2.39, p=0.463), PACS (HR, 1.32, 95% CI 0.95 to 1.83, p=0.099) and POAG (HR, 0.74, 95% CI 0.36 to 1.49, p=0.395) when age and gender were adjusted for. This association was no longer statistically significant (HR, 1.60, 95% CI 0.70 to 3.61, p=0.263) when covariables, such as income, education, body mass index, PVI, history of diabetes and hypertension, were adjusted for. Larger vertical cup-to-disc ratio (VCDR >0.30) was only a significant risk factor in multivariable analysis (HR, 1.60, 95% CI 1.11 to 2.33, p=0.011). CONCLUSIONS: PACG was significantly associated with higher long-term mortality, but this association was likely to be confounded by other systemic risk factors. VCDR >0.3 was the only independent predictor, implying that it may be a marker of ageing and frailty.