Poor adherence to medication in diabetic patients leads to poor glycemic control. Previously we showed that HbA1c decreased by 0.2% with a 25% increase in medication adherence. Whether lower limb amputation is associated with medication adherence independent of or in combination with HbA1c levels in diabetes is unclear. We analyzed data from 16,590 patients with diabetes mellitus whose records on oral hypoglycemic agents were available for at least 1 year. Adherence was evaluated by the proportion of days covered (PDC), with PDC <80% defined as poor adherence. Lower limb amputation was identified by 10 codes and medical procedures. Cox regression model identified variables related to incidence of amputation. In a mean follow-up of 5.3 years, 22 amputation events occurred (0.25/1000 person-years). Multivariate Cox regression analysis indicated that HbA1c level and PDC were independently associated with incidence of amputation (HR (95%CI) 1.19 (0.92-1.54), 0.11 (0.02-0.38)). Compared with PDC ≥80% and HbA1c <8.0%, PDC <80% and HbA1c ≥8.0% had a risk of amputation approximately 5 times higher (Figure). PDC ≥80% and HbA1c <8.0% may present a lower risk of lower limb amputation through enhanced treatment. The combination of PDC and HbA1c values may lead to a more stratified approach to reduce risk of lower limb amputation.
M. Kaneko: None. K. Fujihara: None. M. H. Yamada: None. Y. Yaguchi: None. M. Yamamoto: None. M. Kitazawa: None. S. Kodama: None. H. Sone: Research Support; Self; Astellas Pharma Inc., Eisai Co., Ltd., Kyowa Kirin Co., Ltd., Novo Nordisk, Ono Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co.