National Rates of Lower Extremity Amputation in People With and Without Diabetes in a Multi-Ethnic Asian Population: a Ten Year Study in Singapore

Abstract

Population level data from Asia on amputation rates in people with and without diabetes are extremely limited. Hence it is unclear how the rising diabetes prevalence in Asia has affected the amputation burden. The present study examined national amputation rates in people with and without diabetes in Singapore from 2008 to 2017 in the context of increasing diabetes prevalence and health system changes. This was a retrospective observational study using national population data for ages 16 - 100 years obtained from the Ministry of Health Singapore administrative datasets. Age sex standardised major and toe/ray amputation rates per 100 000 people with diabetes and per 100 000 people without diabetes were calculated. Rates were calculated overall and in each ethnic group (Chinese, Malay, Indian, Others), with trends over time calculated using joinpoint trend analysis. In addition, age specific rates, relative risk (RR) of amputation in diabetics compared with non-diabetics and proportion of amputations in the population attributable to diabetes were also calculated. Between 2008 and 2017, the database included 3.6 million unique individuals, of whom 75% were Chinese, 8.6% Malay, 7.9% Indian, and 8.4% Others. Of those, 413 486 (11%) had diabetes. Major amputation rates in people with diabetes remained stable (2008: 99.5/100 000; 2017: 95.0/100 000 people with diabetes, p= .91) as did toe/ray amputation rates. Rates in people without diabetes were substantially lower, with major amputation rates decreasing significantly (2008: 3.0/100 000; 2017: 2.1/100 000 people without diabetes, 3% annual reduction, p= .048). Diabetes related amputation rates were highest in Malays and lowest in Chinese. Diabetes related major amputation rates declined significantly among Chinese (3.1% annual reduction, p < .038). While the RR for amputations in diabetes remained stable, the proportion of major amputations attributable to diabetes increased from 63.6% in 2008 to 81.7% in 2017 (3% annual increase, p= .003). Diabetes related major and toe/ray amputation rates have remained stable but relatively high in Singapore compared with other countries, and the proportion of amputations attributable to diabetes has increased over time. More research is needed to understand the aetiopathological, sociocultural, and health system factors that may underlie the continued high rates of diabetes related amputations in this population.