To Örebro University

OBJECTIVES: This study examines the recent national and regional incidence of lower limb amputations (LLAs) in Sweden and their annual changes.

DESIGN: Observational study using Swedish national register data.

METHODS: We identified all initial amputations in Sweden from 2008 to 2017 in individuals 18 years or older using the national inpatient register. The amputations were categorized into three levels: High proximal (through or above the knee joint), low proximal (through the tibia to through the ankle joint), and partial foot amputations. To examine the national and regional incidence and annual changes, the age-, sex- and region-specific population count each year was used as the denominator and Poisson regression or negative binomial regression models were used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) adjusted for age and sex.

RESULTS: The national annual incidence of LLAs was 22.1 per 100,000 inhabitants, with a higher incidence in men (24.2) than in women (20.0). The incidence of LLAs (all levels combined) declined during the study period, with an IRR of 0.984 per year (95% CI, 0.973-0.994). This was mainly due to a decrease in high proximal amputations (0.985, 95% CI 0.974-0.995) and low proximal amputations (0.973, 95% CI 0.962-0.984). No change in the incidence of partial foot amputations was observed (0.994, 95% CI 0.974-1.014). Such declines in LLA incidence (all levels combined) were observed in 9 out of 21 regions. Compared to the national average and with adjustment for age, sex, diabetes and artery disease, the regional IRR varied from 0.85-1.36 for all LLAs, from 0.67-1.61 for high proximal amputations, from 0.50-1.51 for low proximal amputations and from 0.13-3.68 for partial foot amputations.

CONCLUSIONS: The incidence of LLAs has decreased in Sweden. However, regional variations in incidence, time trends, and amputation levels warrant more research.