Risk factors for lower extremity amputation among patients with diabetes in Singapore

Abstract

Background Among other risk factors, renal disease and ethnicity have been associated with diabetic lower extremity amputation (LEA) in Western populations. However, little is known about risk factors for LEA among Asian patients. Objective The objective was to assess the proportion of hospitalized patients with diabetes who have a LEA among all hospital patients with diabetes mellitus (DM) and to investigate risk factors for diabetic LEA (especially renal disease and ethnicity) using hospital discharge database. Method A retrospective study of hospital discharge database (2004–2009) was performed to identify patients with DM, LEA and renal disease using the International Statistical Classification of Diseases and Related Health Problems, Ninth Revision, Australian Modification codes. Results Of 44 917 hospitalized patients with DM during the 6 years, 7312 (16.3%) patients had renal disease, and 1457 (3.2%) patients had LEA. DM patients with renal disease had significant higher rates of LEA (7.1%) compared to DM patients without renal disease (2.5%, P<.001). The differences were present for foot (2.7% vs. 1.2%), ankle or leg (2.8% vs. 0.9%), and knee or above amputation (1.6% vs. 0.4%, all P<.001). Malays had the highest rate of diabetic LEA (5.1%), followed by Indians (3.0%), Chinese (3.0%), and others (2.3%, P<.001). In logistic regression analyses, renal disease and ethnicity were significant predictors of diabetic LEA (renal disease: odds ratio 3.2, 95% confidence interval 2.8–3.6; ethnicity: odds ratio, 1.6, Malays vs. Chinese, P<.001; 1.0, Indians vs. Chinese, P=.784) after adjustment for age, gender, and year of discharge. Conclusion DM patients with renal disease and Malay ethnicity had higher rates of LEA in this Asian patient population. Malay patients with DM and diabetic patients with renal disease should be considered as high-risk groups for LEA and therefore screened and monitored systematically.