Spine Journal - 2026-06-11 - Journal Article
Diabetic and Non-Diabetic Foot Ulcerations Are Independently Associated With Spinal Infection.
Patetta MJ, Mzeihem M, Cummings C, Mardjetko SM, Cheng W, Danisa OA
Topics
Key Takeaway
Foot ulceration—diabetic or non-diabetic—independently predicts spinal infection within 2 years, with diabetic foot ulcer conferring OR 2.55 for spinal infection and OR 3.29 specifically for spinal osteomyelitis versus diabetic patients without ulcers.
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Summary
This study used PearlDiver administrative claims data to determine whether foot ulceration independently predicts spinal infection beyond diabetic status alone, matching cohorts on comorbidity burden, BMI, renal disease, and immunologic status. DFU patients had OR 2.55 for spinal infection versus diabetic patients without ulcers, and NDFU patients had higher spinal infection rates than DFU patients (1.22% vs 0.95%, OR 1.28). Diabetes alone did not confer additional spinal infection risk once ulceration was present, implicating the ulcer as the primary hematogenous seeding source.
Key Limitation
ICD-based outcome ascertainment cannot distinguish incidental coding from clinically confirmed spinal infection, risking outcome misclassification that could inflate or deflate true associations.
Original Abstract
BACKGROUND CONTEXT
Spinal infections are associated with substantial morbidity, disability, and health care costs. Diabetes mellitus is a recognized risk factor; however, the contribution of foot ulceration itself, independent of diabetic status, to spinal infection risk has not been adequately explored.
PURPOSE
To evaluate whether diabetic foot ulcer (DFU) and non-diabetic foot ulcer (NDFU) are independently associated with subsequent spinal infection and to determine whether ulceration confers risk beyond diabetes alone.
STUDY DESIGN/SETTING
Retrospective matched cohort study using a nationwide administrative claims database (PearlDiver) with 2-year follow-up.
PATIENT SAMPLE
Adults with foot ulceration were stratified into DFU and NDFU cohorts. Separately, patients with diabetes were stratified into those with DFU and those without foot ulcers (D-NFU). After 1:1 matching, 514,370 patients with foot ulcers and 660,796 patients with diabetes were included.
OUTCOME MEASURES
Self-report measures were not available. Physiologic measures included development of spinal infection within 2 years, defined as spinal osteomyelitis, discitis, spinal epidural abscess, or vertebral infection identified using diagnostic codes. Functional measures were not available.
METHODS
Cohorts were matched on age, sex, Elixhauser Comorbidity Index, body mass index, tobacco use, chronic kidney disease, immunologic disorders, socioeconomic indicators, and diabetes type when applicable. Multivariable logistic regression was performed to evaluate independent associations.
RESULTS
Among patients with diabetes, DFU was associated with increased odds of spinal infection compared with D-NFU (OR 2.55; 95% CI 2.41-2.70), including spinal osteomyelitis (OR 3.29; 95% CI 3.06-3.53). Among patients with foot ulcers, NDFU was associated with higher rates of spinal infection compared with DFU (1.22% vs 0.95%; OR 1.28; 95% CI 1.22-1.35) and remained independently associated on multivariable analysis (OR 1.24; 95% CI 1.17-1.31).
CONCLUSIONS
Foot ulceration was independently associated with increased odds of subsequent spinal infection regardless of diabetic status. Among patients with diabetes, the presence of a foot ulcer was associated with more than twofold higher odds of spinal infection, while diabetes was not associated with further increased odds once ulceration is present. Incorporating foot ulcer status into clinical risk stratification may facilitate suspicion of spinal infection in high-risk patients.