Adherence to General Diabetes and Foot Care Processes, with Prompt Referral, Are Associated with Amputation-Free Survival in People with Type 2 Diabetes and Foot Ulcers: A Scottish National Registry Analysis

Abstract

Aims. To compare different packages of care across care providers in Scotland on foot-related outcomes. Methods. A retrospective cohort study with primary and secondary care electronic health records from the Scottish Diabetes Registry, including 6,845 people with type 2 diabetes and a first foot ulcer occurring between 2013 and 2017. We assessed the association between exposure to care processes and major lower extremity amputation and death. Proportional hazards were used for time-to-event univariate and multivariate analyses, adjusting for case-mix characteristics and care processes. Results were expressed in terms of hazard ratios with 95% confidence intervals. Results. 2,243 (32.7%) subjects had a major amputation or death. Exposure to all nine care processes at all ages ( $\text{HR}=0.63$ ; 95% CI: 0.58-0.69; $p<.001$ ) and higher foot care attendance in people aged >70 years ( $\text{HR}=0.88$ ; 0.78-0.99; $p=.03$ ) were associated with longer major amputation-free survival. $\text{Waiting}\text{time}\ge 12$ weeks between ulceration and clinic attendance was associated with worse outcomes ( $\text{HR}=1.59$ ; 1.37-1.84; $p<.001$ ). In $\text{people}>70$ years, minor amputations were associated with improved major amputation-free survival ( $\text{HR}=0.69$ ; 0.52-0.92; $p=.01$ ). Conclusions. Strict adherence to a standardised package of general diabetes care before foot ulceration, timely foot care after ulceration, and specific treatment pathways were associated with longer major amputation-free survival among a large cohort of people with type 2 diabetes in Scotland, with a larger impact on older age groups.