Diabetic foot ulcers (DFUs) are a common and severe, yet preventable complication associated with diabetes. The INTELLIN app promotes early health service engagement to prevent ulcer recurrence. This analysis aimed to determine the level of clinical benefit that is required for INTELLIN compared with standard of care (SoC) to be cost-effective in adults with a recently healed DFU in the UK from a National Health Service perspective. This analysis ran in parallel with INDUCE, a feasibility study (N=15) to explore the implementation and acceptance of INTELLIN.
A cohort-based Markov model was developed with six health states: post-ulcer, non-severe ulcer, severe ulcer, amputation, post-amputation and death. Ulcer severity was defined by Site, Ischemia, Neuropathy, Bacterial Infection, and Depth (SINBAD) score. Patients entered the model in the post-ulcer state, under the assumption that they had a DFU healed in the past 4-12 weeks. The model adopted a lifetime horizon, one-month cycle length and 3.5% discounting rate for costs and outcomes. Baseline characteristics, health state costs, utilities and baseline transition probabilities for model health states were obtained from the literature. Due to limited comparative efficacy data available on the app, a threshold analysis was undertaken to determine the relative reduction in DFU recurrence required for the app to be cost-effective at the UK standard willingness-to-pay threshold (or incremental cost-effectiveness ratio, ICER) of £20,000 per quality-adjusted life year (QALY).
Threshold analyses showed that the app required a relative reduction in DFU recurrence of only 3% (relative risk=0.97) compared with SoC to attain an ICER of £20,000.
The INTELLIN app needs only to provide a small reduction in DFU recurrence compared to SoC to be a cost-effective strategy for the prevention of diabetes complications. This promising result supports the development of a study to evaluate the effectiveness of the app in a larger population size.
© 2020 Published by Elsevier Inc.