Strabismus among aged Medicare beneficiaries: Impact of health status and region

Purpose To describe the effect of health status and geographic region of the United States on the prevalence of strabismus and strabismus surgery in the aged Medicare fee-for-service population. Methods A 5% sample of Medicare claims was used to identify aged beneficiaries diagnosed with strabismus and those having strabismus surgery between 2002 and 2010. The Charlson Comorbidity Index (CCI), a measure of systemic health, was calculated. The regional analysis divided the United States into East, West, Midwest, and South. Analyses were adjusted for age, sex, race, CCI, and region. Results The 5% sample for 2010 included 1,237,469 unique beneficiaries. Strabismus was diagnosed in 8,470 (0.68%) and strabismus surgery was performed on 197 (0.016%). Pooled data from 2002 through 2010 found the prevalence of strabismus increasing significantly with increasing comorbidity (P < 0.0001): 0.52% (CCI, 0), 0.65% (CCI, 1-2), 0.77% (CCI, 3-4), and 0.82% (CCI, 5 or higher). Conversely, the prevalence of strabismus surgery declined slightly with increasing comorbidity (P = 0.088): 0.016% (CCI, 0), 0.017% (CCI, 1-2), 0.015% (CCI, 3-4), and 0.015% (CCI, 5 or higher). The diagnosis of strabismus was made least frequently in the South (P < 0.0001), whereas strabismus surgery was performed more often in the West (P = 0.006). All significant effects remained after adjustment. Conclusions The prevalence of strabismus increases significantly with declining health status; however, health status had little effect on the rate of strabismus surgery. Regional rates of strabismus diagnosis and surgery differ widely.