Optimal antibiotic duration for preventing DFI recurrence remains unclear
medwireNews: Patients who receive more than 3 weeks of antibiotic treatment for diabetic foot infection (DFI) are no less likely to develop further infection than those treated for a shorter duration, study findings indicate.
The analysis also “found no threshold for the optimal duration or route of administration of antibiotic therapy to prevent recurrences of DFI,” report Ilker Uçkay (Geneva University Hospitals, Switzerland) and co-researchers in Diabetes, Obesity and Metabolism.
The study included 482 patients (median age 69 years, 27% women) with 1081 DFI episodes, namely soft tissue infections (n=626), osteomyelitis (n=392), necrosis (n=335), cellulitis (n=322), and large abscesses (n=246).
Overall, 81% of the DFI episodes required surgery with debridement and lavage, and 59% led to amputation. Upon admission, all patients began antibiotic therapy, with a median treatment duration of 20 days overall, and 5 days for intravenous therapy.
During a median follow-up period of 3.3 years, 24.7% of the initial DFI episodes were followed by at least one additional episode, which occurred after a median 30 days for soft tissue DFI and 70 days for osteomyelitis.
Just over half (53%) of subsequent episodes were classed as “clinical recurrences,” while the remainder were considered “microbiological recurrences,” defined as at least partial concordance of the three dominant pathogens isolated from wound cultures between the initial and subsequent DFI episodes.
Cox regression analyses showed that neither the overall duration of antibiotic therapy (more vs less than 3 weeks) nor the duration of intravenous therapy (more vs less than 1 week) was significantly associated with the likelihood for recurrence.
Similar results were observed when clinical and microbiological recurrences were analyzed separately and when the data were stratified by soft tissue infections and osteomyelitis.
When the researchers plotted the duration of antibiotic treatment against the number of DFI recurrences, they found no threshold for an optimal antibiotic duration to prevent recurrence.
Uçkay and co-authors caution that their data are “too preliminary to make strong conclusions.”
“But in view of the known hazards of unnecessary prolonged antibiotic therapy for these types of infections, these data also appear to support electing shorter treatment duration for most DFIs,” they say.
The researchers conclude that this is “an issue ripe for properly designed and sufficiently powered prospective randomized trials.”
By Laura Cowen
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