Non-White Race Is Associated With Higher Risk Of Amputation In Patients With Lower WIfI Scores.

Introduction: Chronic wounds represent a significant source of debilitation and morbidity. Disparate outcomes based upon racial, socioeconomic, and patient-specific factors have been routinely demonstrated in literature. This retrospective cohort study evaluated inpatients with lower extremity wounds who were assessed by a limb preservation service, with an aim to examine differences in amputation rates between White and non-White groups across varying levels of disease severity.

Methods: A retrospective review of prospectively collected data was performed evaluating patients seen by the inpatient limb preservation service at a large academic medical center between 2018 and 2023. Wound, Ischemia, foot infection (WIfI) scores, demographics, and outcomes were collected on the cohort. Patients were categorized into two racial/ethnic groups: HNW (Hispanic and non-White) and NHW (non-Hispanic Whites). Associations between race/ethnicity and amputation outcomes were examined after using a propensity score (PS) model to estimate inverse probability of treatment weights (IPTW) for non-White group membership. IPTW weighting was applied to "balance" race groups on observed covariates when examining differences using 2-way contingency tables.

Results: 696 patients were evaluated, with a primary endpoint of major or minor amputation. 37% of patients were female, and 36% were Hispanic/non-White (HNW). Minor amputations occurred in 20% of patients, and 18% underwent major limb amputations. HNW patients experienced higher rates of both minor (27% vs. 17%; OR 1.8, 95% CL 1.2-2.6) and major amputations (27% vs. 13%; OR 2.4, 95% CL 1.5-3.7). Intervention/revascularization rates did not differ between HNW and NHW patients. In analyses adjusted for confounding using IPTW weighting, differential risk of amputation across WIfI levels was observed in non-White versus White patients (Breslow-Day chi-square P-value: 0.002). However, after Bonferroni adjustment for multiple comparisons, only one of the stratified confidence intervals was significantly associated with risk of any amputation (OR 6.2, 98.75% CL 0.6-65 at WIfI=1; OR 9.2, 98.75% CL 1.7-50 at WIfI=2; OR 2.1, 98.75% CL 0.8-5.2 at WIfI=3; OR 0.9, 98.75% CL 0.5-1.8 at WIfI=4).

Conclusions: Non-White race was significantly associated with lower extremity amputation events even after stratification by WIfI amputation risk score, which is consistent with previous research. However, our findings suggest non-White patients appear to be at higher risk for minor/major limb amputation at lower WIfI scores when controlling for common risk factors. The underlying reasons for this disparity remain unclear, emphasizing the need for further investigation and highlighting the potential impact of WIfI scores in risk stratification and clinical decision-making. Future research is needed to elucidate the underlying mechanisms contributing to these disparities and develop effective strategies to address and mitigate racial disparities in patients with lower extremity wounds.