Abstract
Purpose: :
Estimate and compare the risk of mortality for Exudative (Wet) AMD patients to Control Cohort in the Medicare population.
Methods: :
This observational retrospective study consisted of Medicare beneficiaries who were included in the standard 5% analytic sample, however, excluding those enrolled in Medicare Managed Care plan. The database provides information for Medicare Part A and B coverage, HMO participation, date of death, and some demographic information. The cohort of Wet AMD included those 65 years of age or older on January 1, 1999 and were followed for 5 years until 2003. These individuals had a diagnoses code for AMD (ICD–9: 362.52, 362.42, or 362.43) during the study period. The Wet AMD cohort was stratified further into four vision loss groups (no vision loss, moderate vision loss, severe vision loss, and blindness). The comparison cohort, excluded those with a diagnosis for Wet AMD. Adjusted hazard ratios of mortality were conducted for each Wet AMD vision loss group compared to the control cohort adjusting for age stratified into 5 groups, gender, and race. A Cox regression model was conducted controlling for vision status and age to see whether they were predictors of mortality.
Results: :
The adjusted hazard ratios showed that Wet AMD patients with vision stratifications had no significant difference in mortality rates than the control patients except for those with blindness. The Wet AMD patients with blindness had a 50% significantly higher probability of mortality in comparison to the control group. After controlling for Wet AMD, the probability of mortality increases significantly with greater vision loss, so those who are blind independent of Wet AMD had a 1.99 risk for mortality compared to no vision loss. In addition, age has shown a higher risk of mortality as the patients’ age increases. Those patients over the age of 85 had a 6.3 times more likelihood of mortality compared to those younger than 65 years. Patients with Wet AMD show a negative correlation with mortality after adjusting for age and vision.
Conclusions: :
Vision loss and age are predictors of mortality rates, with positive correlations. Although Wet AMD did not show to be an independent risk factor for mortality, there may be some association since these patients are typically older than 65 years and have progressive vision loss. These data may exclude patients who have only Medicare Part A. Patients with Wet AMD need to be managed and treated to delay the progression of vision loss. Preserving vision is a potential factor in reducing mortality in this population.
Keywords: aging • age-related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment