gms | German Medical Science

Background: There is no clinical guideline that states the optimal time for an individual patient with end stage osteoarthritis to undergo primary total hip replacement, and patients often receive the operation with delay to maximise the expected net clinical benefits of surgery. However, there is evidence that delaying total hip replacement may produce long term health-related quality of life losses to patients relative to timely surgery. The economic implications of delaying surgery are not known.

Question: To assess the cost and health benefits of timely primary Total Hip Replacement (THR) for functionally independent adult patients with osteoarthritis (OA) compared to: a) non-surgical therapy followed by THR once the patient has progressed to a functionally dependent state (“Delayed THR”), and b) non-surgical therapy alone (Medical Therapy). The study was conducted from the perspective of the German Social Health Insurance (SHI).

Methods: Data from national hip arthroplasty registers and a systematic review of the published literature on costs and treatment outcomes of end-stage OA patients in Germany were used to populate a cost-effectiveness Markov model of OA treatment adapted for Germany from a previously published model. The model considers non-surgical management, rehabilitation, follow-up, THR and revision operations, and the events of peri-operative mortality, implant failure, 90-day post-operative complications and background death based on population life tables. The model represents the lifetime experience of a patient cohort following their treatment choice. Following German methodological practice, a 5% annual discount rate was used in the base case analysis of costs (in year 2013 prices) and health outcomes (QALYs).

Results: The average cost of lifelong investment in timely and delayed THR at age 55 was estimated to be 28,560 Euro vs 26, 767 Euro respectively. Medical treatment alone cost 27,266 Euro. There is a significant difference in health outcomes between timely intervention, which resulted in 20.7 Quality Adjusted life years (QALY), delayed THR, 16.8 QALY, and treatment with medication alone, 10.3 QALY. This effect was fully due to improvement in health-related quality of life, since patient survival was only affected by the peri-operative mortality risk associated with THR; similar results were found when benefits in life expectancy due to avoidance of physical disability were accounted for. Discounting future costs and health outcomes, the incremental cost per QALY gained by timely over delayed (median delay of 11 years) THR therapy was €1,081 and €1246 in women treated at age 55 and age 65, respectively. In men the respective figures were €1,099 and €1,887. Sensitivity analyses suggest these results are robust to uncertainty.

Discussion: Timely THR is likely to be cost-effective, generating large health related quality of life benefits to patients at low additional cost to the SHI system. Although the return on such investment of scare resources is substantial, its budgetary implications nevertheless deserve a careful investigation to identify the characteristics of patient subgroups that are able to benefit most from THR in general and timely THR in particular, in the light of current demographic trends and increasingly constrained healthcare budgets.

Practical implications: Orthopaedic surgeons may be overlooking the negative long term quality of life and economic losses associated with decisions to delay hip replacement surgery for end-stage OA made on the basis of short term risk-benefit calculations. Policy makers should consider policies to internalise (account for) the long term costs of delayed THR in clinical decisions in order to significantly improve the health related quality of life of patients.