Glaucoma-Associated Long-term Mortality in a Rural Cohort from India: The Andhra Pradesh Eye Disease Study

Abstract

 

Purpose

 

To evaluate glaucoma-associated mortality in a longitudinal cohort in rural India.

 

Methods

 

Between 1996-2000, 10,293 participants of all ages from three rural and one urban location were examined in the Andhra Pradesh Eye Diseases Study (APEDS1). About a decade later (June 2009-Jan 2010), participants in the three rural areas were traced (APEDS2): the urban sample no longer existed. History of death or migration were recorded for those not available. All underwent detailed examination, including measurement of intraocular pressure (IOP), cup:disc ratio and visual field testing. Glaucoma was defined using International Society of Geographic and Epidemiologic Ophthalmology criteria. Hyperopia and myopia were defined as spherical equivalent of >+/- 0.5D Sph. Mortality hazard ratio (HR) analysis was performed using Cox proportional hazard regression for those ≥40 years at APEDS1, adjusting for age, sex, diabetes, hypertension, body mass index, smoking, education, visual impairment, cataract and age related macular degeneration.

 

Results

 

At APEDS1, there were 2790 participants aged >40 years in the three rural areas. 1322 (47.4%) were male. Overall, 739 (26.5%) had died and 172 (6.2%) had migrated. Migration was higher (52.3%) in females. At baseline, 45 participants had primary open angle glaucoma (POAG) and 66 had primary angle closure disease (PACD). At follow-up, 22/45 (48.8%) with POAG and 22/66 (33.3%) with PACD had died. Univariate analysis indicated increased hazard of mortality in those with POAG (HR=1.9 [95% CI: 1.23-2.94]), pseudoexfoliation (HR=2.79 [95% CI: 2.0-3.89]), myopia (HR=1.78 [95% CI: 1.54-2.06]) and unit increase in cup:disc ratio (HR=4.49 [95% CI: 2.64-7.64]). Hyperopia was protective (HR=0.85 [95% CI: 0.71-1.0]). There was no association with PACD, IOP or family history of glaucoma. In multivariable analysis, cup:disc ratio remained independently associated with mortality with a HR of 2.5 [95% CI: 1.3-5.1] for each unit increase in cup:disc ratio. The association remained significant when other ocular parameters were included in the model (HR=2.1 [95% CI: 1.03-4.2]).

 

Conclusions

 

To the best of our knowledge, ours is the first longitudinal study to assess mortality and its association with glaucoma in a longitudinal rural cohort from India. Increased cup:disc ratio could be a marker for aging and needs further validation in elderly cohorts in other populations.

 

Keywords: 459 clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • 463 clinical (human) or epidemiologic studies: prevalence/incidence • 464 clinical (human) or epidemiologic studies: risk factor assessment