Optimising the current model of care for knee osteoarthritis with the implementation of guideline recommended non-surgical treatments: a model-based health economic evaluation

Abstract

AIMS OF THE STUDY: Structured exercise, education, weight management and painkiller prescription are guideline recommended non-surgical treatments for patients suffering from knee osteoarthritis. Despite its endorsement, uptake of guideline recommended non-surgical treatments remains low. It is unknown whether the implementation of these treatments into the current model of care for knee osteoarthritis would be cost-effective from a Swiss statutory healthcare perspective. We therefore aimed to (1) assess the incremental cost-effectiveness ratio of an optimised model of care incorporating guideline recommended non-surgical treatments in adults with knee osteoarthritis and (2) the effect of total knee replacement (TKR) delay with guideline recommended non-surgical treatments on the cost-effectiveness of the overall model of care. METHODS: A Markov model from the Swiss statutory healthcare perspective was used to compare an optimised model of care incorporating guideline recommended nonsurgical treatments versus the current model of care without standardised guideline recommended non-surgical treatments. Costs were derived from two Swiss health insurers, a national database, and a reimbursement catalogue. Utility values and transition probabilities were extracted from clinical trials and national population data. The main outcome was the incremental cost-effectiveness ratio for three scenarios: "base case" (current model of care vs optimised model of care with no delay of total knee replacement), "two-year delay" (current model of care vs optimised model of care + two-year delay of total knee replacement) and "five-year delay" (current model of care vs optimised model of care + five-year delay of total knee replacement). Costs and utilities were discounted at 3% per year and a time horizon of 70 years was chosen. Probabilistic sensitivity analyses were conducted. RESULTS: The "base case" scenario led to 0.155 additional quality-adjusted life years (QALYs) per person at an additional cost per person of CHF 341 (ICER = CHF 2,203 / QALY gained). The "two-year delay" scenario led to 0.134 additional QALYs and CHF -14 cost per person. The "five-year delay" scenario led to 0.118 additional QALYs and CHF -501 cost per person. Delay of total knee replacement by two and five years led to an 18% and 36% reduction of revision surgeries, respectively, and had a cost-saving effect. CONCLUSION: According to this Markov model, the optimisation of the current model of care by implementing guideline recommended non-surgical treatments would likely be cost-effective from a statutory healthcare perspective. If implementing guideline recommended nonsurgical treatments delays total knee replacement by two or five years, the amount of revision surgeries may be reduced.