Validity of Quality of Life Measurement in Economic Evaluations in Total Joint Replacement: Agreement between Western Ontario and McMasters' Osteoarthritis Index (WOMAC) and the EuroQOL 5D (EQ-5D) Utility scores
Master of Science
Health and Rehabilitation Sciences
Health economic evaluations are commonly conducted through a cost-utility analysis, where health benefits are measured using utility scores. A common utility measure is the European Quality of Life (EQ-5D). Osteoarthritis (OA) research studies commonly use disease-specific quality of life tools such as the Western Ontario and McMaster’s Universities Osteoarthritis Index (WOMAC) to derive utility scores, but the validity of this method is unknown. This research aims to determine the agreement between utility scores derived from WOMAC and the EQ-5D surveys among patients who have undergone Total Joint Replacement (TJR). To estimate the agreement, we calculated an intraclass correlation coefficient (ICC) and its 95% confidence interval (CI) and produced Bland Altman plots. Our results indicate good agreement between the two scores, as seen with the ICC value of 0.85, 95% CI (0.82 - 0.87).
Summary for Lay Audience
Osteoarthritis is a common chronic condition that affects the function of the joints. With a prevalence rate of 14.2% and projections indicating that the number of Canadians diagnosed with OA is set to increase, the economic burden posed by OA is also set to increase. Canadians rely on the publicly funded healthcare system to meet their healthcare needs. One of the significant issues with publicly funded healthcare programs is that the needs of the public outweigh the available healthcare resources. Therefore, decision-makers need to identify which healthcare needs will provide the greatest benefit to the largest possible majority of the public; since each decision comes with a cost and benefit. One of the methods often employed within healthcare to identify the costs and benefits associated with each of these decisions is the use of health economic evaluations.
With an increasingly aging population and the projected number of patients with OA, the resources required to treat these individuals will increase. As a result, more economic evaluations are being conducted within osteoarthritis research. An essential metric within these evaluations are utility scores. A utility score is a numerical value representing a patient’s preference for each health state, with a value of 1 representing perfect health and 0 representing the worst imaginable health state from the patient’s perspective. These values can be derived either directly using utility instruments or by converting disease-specific quality of life surveys into utility scores. However, the validity of converting disease-specific scores into utility scores following total joint replacement is unknown.
Therefore, this thesis aims to compare the utility scores between the European Quality of Life (EQ-5D-5L) and the Western Ontario and McMasters Osteoarthritis Index (WOMAC) among patients who have undergone total joint replacement surgery of the hip and or knee joints.
Valamparampil, Sanju, "Validity of Quality of Life Measurement in Economic Evaluations in Total Joint Replacement: Agreement between Western Ontario and McMasters' Osteoarthritis Index (WOMAC) and the EuroQOL 5D (EQ-5D) Utility scores" (2022). Electronic Thesis and Dissertation Repository. 8856.