The Use of Rifampin Therapy to Treat Diabetic Patients with Osteomyelitis of the Foot in the Veterans Health Administration: Patient Characteristics and Clinical Outcomes

BACKGROUND: Nearly 25% of Veterans Health Administration (VHA) patients are diagnosed with diabetes mellitus (DM). Among DM patients, the lifetime incidence of foot ulcers is 15%. Infection is a common complication of foot ulcers and 20–60% of infections result in diabetic foot osteomyelitis (DFO). Current treatment guidelines do not endorse any specific antibiotic agent for DFO, but small clinical trials suggest the addition of rifampin to antimicrobial regimens results in improved cure rates for osteomyelitis. METHODS: Using VHA databases, we identified index DFO cases from 2009 to 2013 and extracted patient and infection characteristics including demographics, comorbidities, chronic medications, antibiotic regimens, and microbiology data when present. We analyzed the subset of patients alive, without high-level amputation, and treated with antibiotics at 90 days after diagnosis. We summarized patient characteristics and compared a composite endpoint of amputation or death within 2 years of DFO diagnosis among those treated with rifampin to those not treated with rifampin. RESULTS: In total, 10,736 DFO cases met our criteria (Figure). Of these, 151 were considered treated with rifampin, based on 14 or more days of rifampin initiated within 90 days of diagnosis; 10,551 were unexposed to rifampin; and 34 were excluded for late or short treatment with rifampin. We observed significant differences between patients treated with and without rifampin (Table) and 44% of rifampin-treated patients were seen in 14 facilities. Amputation or death at 2 years was observed in 44 (29%) of patients treated with rifampin and 4,007 (38%) of patients not treated with rifampin (P = 0.03). CONCLUSION: Rifampin was rarely used in the treatment of DFO in the VHA and a few facilities accounted for a large proportion of rifampin-treated cases. We observed higher rates of amputation-free survival in patients treated with rifampin, but in the presence of notable confounders including age, comorbidities, and organism. DISCLOSURES: E. Saade, Steris: Grant Investigator, Grant recipient. Janssen: Grant Investigator, Research grant. Sequiris: Grant Investigator, Research grant. Pfizer: Grant Investigator, Research grant. R. A. Bonomo, Entasis: Grant Investigator, Research grant. Allecra: Grant Investigator, Research grant. Wockhardt: Grant Investigator, Research grant. Merck: Grant Investigator, Research grant. Roche: Grant Investigator, Research grant. GSK: Grant Investigator, Research grant. Allergan: Grant Investigator, Research grant. Shionogi: Grant Investigator, Research grant