Inflammatory biomarkers and risk of re-amputation after transtibial or transfemoral amputation in diabetic patients

Re-amputation after transtibial or transfemoral amputation may compromise healing and rehabilitation. Inflammatory markers may aid risk stratification.

To evaluate associations between preoperative inflammatory biomarkers, especially systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI), and re-amputation risk.

Retrospective cohort study.

We included 146 consecutive diabetic patients who underwent transtibial or transfemoral amputation for diabetic foot-related complications from January 2021 to December 2023. Patients with documented or imaging-confirmed peripheral arterial disease were excluded. Laboratory values within 48 hours before surgery were analyzed. Re-amputation was defined as additional bone resection at the same or a more proximal level. Patients without re-amputation were censored at death or last follow-up. Cox regression and receiver operating characteristic analyses were performed.

Re-amputation occurred in 26 patients (17.8%). Re-amputation was associated with higher white blood cell, neutrophil, monocyte, platelet, C-reactive protein (CRP), SII, SIRI, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio values. In exploratory multivariable Cox models adjusted for age and amputation level, SIRI (hazard ratio [HR], 1.048; 95% confidence interval [CI], 1.022-1.076; p < .001), SII per 1,000-unit increase (HR, 1.066; 95% CI, 1.011-1.123; p = .018), and CRP per 10 mg/L increase (HR, 1.094; 95% CI, 1.053-1.137; p < .001) remained associated with re-amputation. CRP had the highest area under the curve (0.762), followed by SII (0.746) and SIRI (0.740).

Higher preoperative systemic inflammatory burden was associated with re-amputation. CRP performed best, while SII and SIRI showed moderate complementary value. External validation is required.