Background: The optimal duration of antibiotic therapy for soft-tissue infections of the diabetic foot (ST-DFI) remains unknown.

Objective: We determine if antibiotic therapy after debridement for a short (10 days), compared with a long (20 days), duration for ST-DFI results in similar rates of clinical remission and adverse events (AE).

Summary background data: The optimal duration of systemic antibiotic therapy, after successful debridement, for soft tissue infections of diabetic patients is unknown. Because of the high recurrence risk, overuse is commonplace.

Methods: This was a randomized, controlled, non-inferiority pilot trial of cases of diabetic foot infection (excluding osteomyelitis) with the primary outcome of "clinical remission at two-months follow-up".

Results: Among 66 enrolled episodes (17% females; median age 71 years), we randomized 35 to the 10-day arm and 31 to the 20-day arm. The median duration of the parenteral antibiotic therapy was 1 day, with the remainder given orally. In the intention-to-treat (ITT) population, we achieved clinical remission in 27 (77%) patients in the 10-day arm compared to 22 (71%) in the 20-days arm (p = 0.57). There were a similar proportion in each arm of AE (14/35 versus 11/31; p = 0.71), and remission in the per-protocol (PP) population (25/32 vs. 18/27; p = 0.32). Overall, eight soft tissue DFIs in the 10-day arm and five cases in the 20-day arm recurred as a new osteomyelitis (8/35 [23%] versus 5/31 [16%]; p = 0.53). Overall, the number of recurrences limited to the soft tissues was 4 (6%). By multivariate analysis, rates of remission (ITT population, hazard ratio 0.6, 95%CI 0.3-1.1; PP population 0.8, 95%CI 0.4-1.5) and AE were not significantly different with a 10-day compared to 20-day course.

Conclusions: In this randomized, controlled pilot trial, post-debridement antibiotic therapy for soft tissue DFI for 10 days gave similar (and non-inferior) rates of remission and AEs to 20 days. A larger confirmatory trial is under way.