Purpose:
To determine risk factors associated with development of a branch retinal vein occlusion (BRVO) among a large group of US managed-care plan beneficiaries followed longitudinally.
Methods:
All beneficiaries age ≥55 years continuously enrolled for ≥2 years in a managed care network from 2001-2009 and had ≥2 visits to an eye-care provider during that time were identified. Non-incident cases of BRVO were excluded. Multivariable Cox regression analyses were performed to identify sociodemographic factors, ocular and non-ocular conditions that were associated with the development of a BRVO.
Results:
Of the 492488 enrollees who met the inclusion criteria, 2283 (0.46%) developed a BRVO during the 4.7 (SD 1.7) years they were in the plan. Blacks (adjusted hazard ratio (HR)=1.36, 95% CI (confidence interval) 1.13-1.64, p=0.001) and Asian Americans (HR=1.37, 95% CI 1.01-1.86, p=0.04) had an increased hazard of developing BRVO relative to non-Hispanic whites. After adjustment for confounding factors, individuals with hypertension (HTN) alone (HR=1.77, 95% CI 1.36-2.31, p<0.0001) or HTN coupled with diabetes mellitus (DM) and hyperlipidemia (HR=1.43, 95% CI 1.12-1.84, p=0.005) had an increased hazard of developing a BRVO compared to those with none of these conditions. Disease severity was also important; compared to a 36% increased hazard for enrollees with uncomplicated HTN (HR=1.36, 95% CI 1.17-1.57, p<0.0001), those enrollees with end-organ damage caused by HTN had a 108% increased hazard of developing BRVO (HR=2.08, 95% CI 1.75-2.47, p<0.0001). While there was no association between uncomplicated DM and BRVO (adjusted HR=0.91, 95% CI 0.80-1.04, p=0.2), individuals with end-organ damage from DM had a 36% increased hazard of developing BRVO as compared to those without DM (HR=1.36, 95% CI 1.18-1.57, p<0.0001). Although cerebrovascular disease was associated with an increased hazard of developing BRVO (HR=1.34, 95% CI 1.19-1.52, p<0.0001), other diseases of the vascular system (deep venous thrombosis / pulmonary embolism, peripheral vascular disease, hypercoagulable state, myocardial infarction) or anticoagulant use did not increase the risk of BRVO (p>0.10 for all comparisons).
Conclusions:
Conditions that reflect underlying arteriosclerosis (such as HTN, advanced DM, or history of CVA) are strong risk factors for BRVO. Markers of atherosclerosis, such as PVD or history of MI, do not appear to increase the hazard of developing a BRVO. Likewise, disorders of the venous system (hypercoagulability or history of DVT/PE) do not increase BRVO risk. These findings suggest that arterial hardening contributes to elevated BRVO risk and that venous disorders are not significantly associated with BRVO.