Abstract
Purpose: :
We examined regional variation in glaucoma prevalence based on diagnostic billing codes among the Medicare population.
Methods: :
Medicare beneficiaries with a glaucoma diagnosis code on at least one claim for a visit to an ophthalmologist or optometrist were identified using 2002-2008 physician billing claims. The denominator for prevalence estimates was limited to those aged 65 and older with continuous Medicare Part B coverage and no HMO enrollment for each calendar year. State of residence was grouped into one of 9 geographic regions according to the Area Resource File classification. Annual prevalence estimates for open angle suspect, open angle (OAG), angle closure suspect and angle closure glaucoma (ACG) were calculated for each region and adjusted for differences in age, gender and race/ethnicity.
Results: :
Prevalence of any glaucoma increased from 10.4% in 2002 to 11.9% by 2008. Most of this increase was explained by increased prevalence of OAG suspects, 3.2% in 2002 rising to 4.5% by 2008, while prevalence of other glaucoma types remained constant. In 2008, OAG prevalence was 6.4% overall, and was significantly greater in Black Americans (11.2%), Hispanics (7.6%) and women (6.9%) and significantly increased with age (p<0.0001 for all). Prevalence of ACG suspects and ACG were 0.3% and 0.2%, respectively, and both were more prevalent among Asian Americans than Whites. Prevalence of ACG peaked among beneficiaries aged 70 to 74 years. Overall glaucoma prevalence varied significantly by geographic region, even after adjustment for age, gender and race/ethnicity. In 2008, OAG prevalence ranged from a low of 6.3% (95% CI: 6.1, 6.5) in the East South Central region (AL, KY, MS, TN) and 6.5% (95% CI: 6.3, 6.7) in the Mountain region (AZ, CO, ID, MT, NM, NV, UT, WY) to 8.2% (95% CI: 8.0, 8.3) in the Mid-Atlantic (NJ, NY, PA) and 8.3% (95% CI: 8.1, 8.5) in New England (CT, MA, ME, NH, RI, VT). Beneficiaries in the Mid-Atlantic and New England were more likely to make an eye care visit during 2008 (Mid-Atlantic OR: 1.30; 95% CI: 1.28, 1.32; New England OR: 1.54, 95% CI: 1.51, 1.57) compared to East South Central beneficiaries.
Conclusions: :
Medicare visits billed for OAG suspect steadily increased since 2002, when the Ocular Hypertension Treatment Study results demonstrated a treatment benefit for OAG suspects. Higher glaucoma diagnosis prevalence was found in regions with more eye care visits.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence