Racial and Ethnic Differences in Microalbuminuria Testing among Elderly Medicare Beneficiaries with Diabetes

Objective: About 40% of diabetic patients may develop chronic kidney disease (CKD). Microalbuminuria testing is a nephropathy screening test that can effectively detect kidney malfunction early and delay or prevent the onset of CKD. However, the microalbuminuria testing rate among elderly diabetic patients is low. This study examines the determinants of racial/ethnic differences in testing between elderly blacks, whites, Asians, and Hispanics.

Methods: We used the Chronic Conditions Warehouse 5% random sample diabetes cohort of fee-for-service Medicare beneficiaries aged 67 or older as of 1/1/2003 (n=233,515). Persons who had interrupted enrollment, developed CKD, or died in 2003 or 2004 were excluded (final n=158,253). Microalbuminuria tests were identified using Current Procedure Terminology codes: 82042, 82043, 82044, and 84156. The rates and determinants of testing were assessed using generalized linear models adjusted for socio-demographic characteristics, comorbidities, hypertension, and health care use.

Results: The multivariate adjusted rate was 19.5% for whites, compared with 18.8% for blacks (p=0.05), 22.3% for Asians (p=0.0007), and 23.7% for Hispanics (p<0.0001). Older age and lower socio-economic status were associated with lower testing rates. Those with hypertension had higher rates. Visiting an endocrinologist was associated with an increase in testing (almost 3-fold). Increasing numbers of physician office visits were not. The racial/ethnic differences persisted across all physician visit levels.

Conclusions: Annual microalbuminuria testing is not well recognized among physicians and diabetic patients. Despite the similar risk of CKD among blacks and Hispanics, the differences in the testing between them suggest cultural factors may play an important role.