Aims/hypothesis: Diabetes progression and complication risk are different in Asian people compared with those of European ancestry. In this study, we sought to understand the epidemiology of diabetes-related lower extremity complications (DRLECs: symptomatic peripheral arterial disease, ulceration, infection, gangrene) and amputations in a multi-ethnic Asian population.
Methods: This was a retrospective observational study using data obtained from one of three integrated public healthcare clusters in Singapore. The population consisted of individuals with incident type 2 diabetes who were of Chinese, Malay, Indian or Other ethnicity. We examined incidence, time to event and risk factors of DRLECs and amputation.
Results: Between 2007 and 2017, of the 156,593 individuals with incident type 2 diabetes, 20,744 developed a DRLEC, of whom 1208 underwent amputation. Age- and sex-standardised incidence of first DRLEC and first amputation was 28.29/1000 person-years of diabetes and 8.18/1000 person-years of DRLEC, respectively. Incidence of both was highest in individuals of Malay ethnicity (DRLEC, 36.09/1000 person-years of diabetes; amputation, 12.96/1000 person-years of DRLEC). Median time from diabetes diagnosis in the public healthcare system to first DRLEC was 30.5 months for those without subsequent amputation and 10.9 months for those with subsequent amputation. Median time from DRLEC to first amputation was 2.3 months. Older age (p < 0.001), male sex (p < 0.001), Malay ethnicity (p < 0.001), Indian ethnicity (p = 0.014), chronic comorbidities (nephropathy [p < 0.001], heart disease [p < 0.001], stroke [p < 0.001], retinopathy [p < 0.001], neuropathy [p < 0.001]), poorer or missing HbA1c (p < 0.001), lower (p < 0.001) or missing (p = 0.002) eGFR, greater or missing BMI (p < 0.001), missing LDL-cholesterol (p < 0.001) at diagnosis, and ever-smoking (p < 0.001) were associated with higher hazard of DRLEC. Retinopathy (p < 0.001), peripheral vascular disease (p < 0.001), poorer HbA1c (p < 0.001), higher (p = 0.009) or missing (p < 0.001) LDL-cholesterol and missing BMI (p = 0.008) were associated with higher hazard of amputation in those with DRLEC. Indian ethnicity (p = 0.007) was associated with significantly lower hazard of amputation.
Conclusions/interpretation: This study has revealed important ethnic differences in risk of diabetes-related lower limb complications, with Malays most likely to progress to DRLEC. Greater research efforts are needed to understand the aetiopathological and sociocultural processes that contribute to the higher risk of lower extremity complications among these ethnic groups.
Keywords: Amputation; Diabetes-related lower extremity complications; Epidemiology; Incidence rate; Progression; Risk factors.