Bone Biopsy not Superior to Ulcer Bed Biopsy–guided Antibacterial Therapy on Remission of Diabetic Foot Osteomyelitis: A Randomized Controlled Trial

Background Percutaneous bone biopsy is the reference standard for guiding antibiotic therapy in diabetic foot osteomyelitis (DFO). However, ulcer bed biopsies are commonly used in practice. This study aimed to compare 12-month outcomes of patients with conservatively treated DFO whose antibiotic regimens were based on cultures of either percutaneous bone or ulcer bed biopsy. Methods We conducted a multicenter, double-blind randomized clinical trial in 84 adult participants with DFO. All underwent a percutaneous bone biopsy and an ulcer bed biopsy. Participants were randomly allocated to antibiotic treatment based on either bone biopsy cultures or ulcer bed biopsy cultures. The primary outcome, DFO remission, was assessed at 12 months using both intention-to-treat and per-protocol analyses with generalized linear models. Results The remission rate in the bone biopsy group was 31.4% (95% confidence interval [CI], 18.1–48.7) and 39.4% (95% CI, 24.2–57.0) in the ulcer bed biopsy group. The relative risk of not achieving remission at 12 months in the bone biopsy group was 1.13 (95% CI, 0.80–1.60) in the intention-to-treat analyses and ranged from 1.12 to 1.18 in the per-protocol analyses. Antibiotics targeting bacteria identified in the unblinded sample were effective against all bacteria cultured from the blinded sample in 85.9% of cases (n = 61). Conclusions This study found no evidence to recommend bone biopsies prior to the start of antibiotics in patients with DFO. In most cases, the antibiotics targeted bacteria in both samples, possibly contributing to the equivalence of the results in outcomes in both groups.