Diabetes and inflammation in infected chronic wounds

Objective. This study examined the impact of diabetes on inflammatory responses among individuals with infected chronic wounds. The findings provide evidence of the extent to which infection may, go unrecognized among persons with diabetes. Methods. This' study was a secondary analysis of another study. Chronic wounds were assessed for signs of infection and classified as infected or noninfected based on quantitative cultures of wound tissue. Infected wounds were those with greater than 10(5) organisms per gram of wound tissue or containing P-hemolytic Streptococcus. Diabetes status was determined through medical record review. The classical signs of inflammation (ie, pain, erythema, edema, heat, and purulent exudate) were identified using the Clinical Signs and Symptoms Checklist (CSSC). Clinical assessments were blinded to the infection status. Results. Seventeen subjects with infected, nondiabetic foot ulcer wounds were included in the sample. Seven (41%) had type 2 diabetes; none had type 1 diabetes. Diabetes was not associated with wound type, wound size, wound duration, or wound oxygen levels. The frequencies with which each of the 5 signs of inflammation was expressed did not differ by diabetes status with the exception of erythema. Three (43%) of the 7 persons with diabetes expressed erythema in their infected chronic wound compared to 8 (80%) of the 10 persons without diabetes. Conclusions. Because erythema is due to local vasoclilation, the inactivation of nitric oxide by advanced glycosylation endproducts may be a key pathophysiological mechanism that underlies its diminished expression in persons with diabetes.