The Development of Lower Limb Amputations in Finland from 1997 to 2018: A Nationwide Retrospective Registry Study

Objective: To investigate the rates of transfemoral, transtibial foot and toe amputations, and lower limb revascularisations in Finland between 1997 and 2018.

Methods: Retrospective observational cohort study. Data from the Finnish National Hospital Discharge Register for the period 1997 - 2018 were used. The study population covered all patients 20 years and older who underwent lower limb revascularisations or amputations in private and public hospitals during the study period. All (outpatient and inpatient) amputations and revascularisations were included. The age adjusted incidence rates were based on the annual mid populations, which were obtained from the Official Statistics of Finland. Continuous variables were presented as median with interquartile range (IQR) or as mean with standard deviation. The 95% confidence intervals (CI) for the incidence rates were calculated using the Poisson exact method. All changes in incidence were calculated as relative change (%).

Results: A total of 75 230 patients underwent 149 492 lower limb revascularisations and amputations between 1997 and 2018 in Finland. The median (IQR) age of the patients was 73 (65, 80) and 60% of the patients were men. The incidence of all endovascular lower limb revascularisations increased by 159% while the incidence of lower limb amputations increased by 25%. The most notable increase occurred in toe (84%) and foot (107%) amputations, while the incidence of transfemoral amputations remained steady and transtibial amputations decreased by 53%. The first minor-major amputation ratio (CI) increased from 1.13 (1.03 - 1.24) to 1.49 (1.36 to 1.62) during the study period.

Conclusion: The findings of this nationwide cohort study suggest that the incidence of both lower limb revascularisations and amputations is increasing. More specifically, revascularisations are more often performed endovascularly, and the incidence of transtibial amputations is declining, whereas the incidence of toe and foot amputations is increasing.