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Abstract
Introduction This study aimed to examine the association of race and ethnicity on the risk of lower extremity amputations among Medicare beneficiaries with diabetic foot ulcers (DFUs) and diabetic foot infections (DFIs).
Research design and methods A retrospective study included 2011–2015 data of a 5% sample of fee-for-service Medicare beneficiaries with a newly diagnosed DFU and/or DFI. The primary outcome was the time to the first major amputation episode after a DFU and/or DFI were identified using the diagnosis and procedure codes. We used multivariable Cox proportional hazards models to estimate the risk of time to the first major amputation across races, adjusting for sociodemographic and health status factors. Adjusted hazard ratios (aHRs) with a 95% CI were reported.
Results Among 92 929 Medicare beneficiaries newly diagnosed with DFUs and/or DFIs, 77% were whites, 14.3% African Americans (AAs), 3.3% Hispanics, 0.7% Native Americans (NAs), and 4.0% were other races. The incidence rates of major amputation were 0.02 person-years for NAs, 0.02 person-years for AAs, 0.01 person-years for Hispanics, 0.01 person-years for other races, and 0.01 person-years for whites (p<0.05). Multivariable analysis showed that AAs (aHR=1.9, 95% CI 1.7 to 2.2, p<0.0001) and NAs (aHR=1.8, 95% CI 1.3 to 2.6, p=0.001) were associated with an increased risk of major amputation compared with whites. Beneficiaries with DFUs and/or DFIs diagnosed by a podiatrist or primary care physician (aHR=0.7, 95% CI 0.6 to 0.8, p<0.0001, specialists as reference) or at an outpatient visit (aHR=0.3, 95% CI 0.3 to 0.3, p<0.0001, inpatient stay as reference) were associated with a decreased risk of major amputation.
Conclusions Racial and ethnic disparities in the risk of lower extremity amputations appear to exist among fee-for-service Medicare beneficiaries with diabetic foot problems. AAs and NAs with DFUs and/or DFIs were associated with an increased risk of major amputations compared with white Medicare beneficiaries.
- administrative data
- clinical epidemiology
- adult diabetes
- chronic diabetic complications
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Footnotes
Contributors T-WT, DGA, KCC-M, C-YC, DGM, WZ, EC, and W-HLC were involved in study concept and design. TT and WL were involved in the acquisition of the data. T-WT, C-YC, and W-HLC had access to the data and performed statistical analysis. All the authors interpreted the results and were involved in writing and revising the manuscript. T-WT and W-HLC had full access to the data in the study and had final responsibility for the decision to submit for publication.
Funding T-WT was supported by National Institutes of Health/National Institute of Diabetes and Kidney Disease (NIDDK) K23 Career Development Award (K23DK122126).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the University of Arizona Institutional Review Board (1606628218).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data may be obtained from a third party and are not publicly available. The Medicare administrative claim data of a 5% national representative sample is available at the Medicare Coverage Database (CMS.gov)