Risk factors for developing osteomyelitis in patients with diabetic foot wounds

Osteomyelitis worsens the prognosis in the diabetic foot, but predisposing factors remain largely undefined. In a prospectively followed cohort we assessed risk factors for developing osteomyelitis.

We enrolled consecutive persons with diabetes who presented to a managed-care diabetes disease management program. The patients underwent standardized assessments. We monitored for all foot complications, defined infections by criteria consistent with International Working Group guidelines, and defined osteomyelitis as a positive culture from a bone specimen.

1666 persons were enrolled, 50% male, mean age 69 years. Over a mean of 27.2 months of follow-up, 151 patients developed foot infections, 30 (19.9%) of which involved bone. Independent risk factors for osteomyelitis were: wounds that extended to bone or joint (relative risk [RR]=23.1), previous history of a wound prior to enrollment (RR=2.2), and recurrent or multiple wounds during the study period (RR=1.9).

In this study population, managed in a specialized diabetic foot care center, the results suggest that independent risk factors for developing osteomyelitis are deep, recurrent and multiple wounds. These results may help clinicians target their efforts at diagnosing foot osteomyelitis to the highest risk patients.