Exploring potential risk factors for lower limb amputation in people with diabetes-A national observational cohort study in Sweden

Aims: Risk factors for lower limb amputation (LLA) in individuals with diabetes have been under-studied. We examined how 1/demographic and socioeconomic, 2/medical, and 3/lifestyle risk factors may be associated with LLA in people with newly diagnosed diabetes.

Methods: Using the Swedish national diabetes register from 2007 to 2016, we identified all individuals ≥18 years with an incident diabetes diagnosis and no previous amputation. These individuals were followed from the date of diabetes diagnosis to amputation, emigration, death, or the end of the study in 2017 using data from the In-Patient Register and the Total Population Register. The cohort consisted of 66,569 individuals. Information about demographic, socioeconomic, medical, and lifestyle risk factors was ascertained around the time of the first recorded diabetes diagnosis, derived from the above-mentioned registers. Cox proportional hazard models were used to obtain hazard ratios (HR) with 95% confidence intervals (CI).

Results: During the median follow-up time of 4 years, there were 133 individuals with LLA. The model adjusting for all variables showed a higher risk for LLA with higher age, HR 1.08 (95% CI 1.05-1.10), male sex, HR 1.57 (1.06-2.34), being divorced, HR 1.67 (1.07-2.60), smokers HR 1.99 (1.28-3.09), insulin treated persons HR 2.03 (1.10-3.74), people with low physical activity (PA) HR 2.05 (1.10-3.74), and people with an increased foot risk at baseline HR > 4.12. People with obesity had lower risk, HR 0.46 (0.29-0.75).

Conclusions: This study found a higher risk for LLA among people with higher age, male sex, who were divorced, had a higher foot risk group, were on insulin treatment, had lower PA levels, and were smokers. No significant association was found between risk for LLA and education level, country of origin, type of diabetes, blood glucose level, hypertension, hyperlipidemia, creatinine level, or glomerular filtration rate. Obesity was associated with lower risk for LLA. Identified variables may have important roles in LLA risk among people with diabetes.