Lower limb amputation rates among Medicare beneficiaries with diabetic foot ulcers managed with and without native collagen matrix plus PHMB antimicrobial

This study compared rates of non-traumatic lower limb amputations ('amputations') among Medicare beneficiaries with diabetic foot ulcers (DFUs) who initiated purified native type 1 collagen matrix plus polyhexamethylene biguanide (PHMB) antimicrobial (PCMP) versus those beneficiaries who did not receive PCMP.

In this retrospective matched cohort study, two groups of beneficiaries with DFUs were retrospectively identified from 100% Medicare Fee-for-Service Standard Analytic Files (Quarter 1 2015-Quarter 3 2023)-those receiving PCMP within six months of DFU diagnosis (index date=first PCMP claim) and those who did not receive PCMP. Beneficiaries were matched 1:1. Using Wilcoxon signed-rank tests, six-month post-index amputation rates were compared. Stratified analysis evaluated amputation rates among beneficiaries initiating PCMP within 45, 60 or 90 days of DFU diagnosis, with follow-up applications every 7-14 days for one month.

Before matching, beneficiaries receiving PCMP (n=10,939) had greater disease severity, as indicated by longer duration of active ulceration and higher amputation rates in the six months pre-index date than those beneficiaries who never received PCMP (n=657,233). After matching, baseline characteristics were well balanced (n=10,862). During follow-up, beneficiaries receiving PCMP had lower six-month amputation rates than those in the matched non-PCMP cohort (9.9% versus 12.2%, respectively; p<0.001). Beneficiaries with earlier initiation of PCMP within 45, 60 or 90 days of diagnosis had lower six-month amputation rates (4.0%, 4.1% and 4.8%, respectively) compared with non-PCMP recipients (8.4%; all p<0.001).

PCMP was disproportionately used in the management of beneficiaries with more complex DFUs/wound care needs. After adjusting for baseline differences, PCMP use was associated with lower rates of lower limb amputations, particularly with earlier initiation within 90 days of DFU diagnosis.