Cultures of diabetic foot ulcers without clinical signs of infection do not predict outcomes.

OBJECTIVE: We examined associations between ulcer bioburden and ulcer outcomes in neuropathic diabetic foot ulcers (DFUs) that lacked clinical signs of infection. RESEARCH DESIGN AND METHODS: Three dimensions of bioburden (i.e., microbial load, microbial diversity, and the presence of likely pathogens) were measured at baseline using swab cultures obtained by Levine's technique. Subjects were assessed every 2 weeks for 26 weeks to determine the rate of healing and development of infection-related complications. Foot ulcers were off-loaded using total-contact casts and routinely debrided. To establish associations between bioburden and rate of healing, Cox proportional hazards and least squares regression were used after adjusting for ulcer depth, surface area, and duration. RESULTS: A total of 77 subjects completed the study. Sixty-five (84.4%) had ulcers that healed during follow-up; weeks-to-closure ranged from 2 to 26 (median 4.0). Mean (± SD) percent reduction in surface area/week was 25.0% (± 23.33). Five (6.5%) of the DFUs developed an infection-related complication. None of the bioburden dimensions (i.e., microbial load, microbial diversity, or presence of likely pathogens) was significantly associated with weeks-to-closure or percent reduction in surface area per week. Weeks-to-closure was best predicted by ulcer duration, depth, and surface area (c-statistic = 0.75). CONCLUSIONS: Culturing DFUs that showed no clinical signs of infection had no predictive value for outcomes of DFUs managed with total-contact casts and routine debridement. These findings support recommendations of the Infectious Disease Society of America that culturing and antibiotics should be avoided in treating DFUs that show no clinical signs of infection.

Volume Measures Using a Digital Image Analysis System are Reliable in Diabetic Foot Ulcers.

UNLABELLED: Reliable measures of wound size are critical to wound healing research and clinical management. Measurement of full-thickness wounds is increasingly being done using digital images and photogrammetric software, such as VeVMD (Vista Medical, Winnipeg, Manitoba, Canada), to estimate wound volume. The reliability of VeVMD in determining wound volume is unknown. The present study sought to examine the reliability of wound volume measurements obtained using VeVMD. METHODS: A cross-sectional study of adults with full-thickness, neuropathic, diabetic foot ulcers (DFU) at 2 sites in the US Midwest was undertaken. Ulcer images were obtained, stored, and used to obtain measures of wound volume using VeVMD. Four raters independently completed wound measures, and then repeated these measures 2 weeks after the first measurement. Raters were blinded to the comparison measurements. Inter- and intra-rater correlations were computed. RESULTS: Thirty-three enrolled subjects with 33 DFU were included in the analyses. Inter-rater reliability was 0.745 and intra-rater reliability was 0.868. Four ulcers showed noticeably less agreement between raters; these ulcers had small, but deeply recessed areas, resulting in differences in defining the wound margin. When these 4 ulcers were removed, inter- and intra-rater reliabilities were excellent (0.970 and 0.981, respectively). CONCLUSION: Reliabilities of volume measurements obtained with VeVMD were acceptable in DFU, even when raters had different definitions of the ulcer margin or changed their definition from time to time. However, conclusions cannot be drawn regarding the performance of VeVMD in other wound types.