The economic benefit of hip replacement: a 5-year follow-up of costs and outcomes in the Exeter Primary Outcomes Study

Objectives: To assess changes in quality of life and costs of patients undergoing primary total hip replacement using the Exeter prosthesis compared with a hypothetical 'no surgery' group. Design: The incremental quality of life, quality-adjusted life years (QALYs) and cost of Exeter Primary Outcomes Study patients was compared with hypothetical 'no surgery' group over 5 years. Scores from annual SF-36 assessments were converted into utility scores using an established algorithm and the QALY gains calculated from pre-operative baseline scores. Costs included implant costs and length of stay. Setting: Secondary care hospitals. Participants: Patients receiving a primary Exeter implant enrolled in five of seven Exeter Primary Outcomes Study centres. Results: On average, patients gained around 0.8 QALYs over 5 years. Younger and male patients or those with lower body mass index and poorer Oxford Hip Scores were significantly associated with increased QALYs. Treatment costs for a primary episode of care were just over 5000 pound (95% CI 4588 pound to 5812) pound per patient. Compared with 'no surgery', the cost per QALY was 7182 pound (95% CI 6470 pound to 7678) pound, and this remained stable when key cost parameters were varied. The most likely cost per QALY was between 7058 pound and 7220 pound. Older patients (age 75+) cost more, mainly due to longer average hospital stays and had a higher cost per QALY, although this remained below 10 pound 000. Conclusions: 85% of cases had a cost of <20 pound 000 per QALY (with 70% having a cost per QALY under 10 pound 000) compared with no surgery. Cases would be considered cost-effective under currently accepted thresholds (25 pound 000-30 pound 000) compared with 'no surgery'. However, depending on age and severity, younger patients and more severe patients had below average cost per QALYs. These results help to confirm the long-term benefits and cost-effectiveness of total hip replacement in a wide variety of patients using well-established implant models such as the Exeter. However, further and ongoing economic appraisal of this and other models is required for comparative purposes.