EQ-5D-5L utilities per health states in Spanish population with knee or hip osteoarthritis

The objective of this study was to obtain utilities by means of EQ-5D-5L for different health states in patients with knee osteoarthritis (KOA) or hip osteoarthritis (HOA) in Spain, and to compare these values with those used in foreign studies with the aim of discussing their transferability for their use in economic evaluations conducted in Spain.

Primary study: Observational prospective study of KOA or HOA patients in Spain. Sociodemographic and clinical characteristics were collected to characterize the sample. Utilities were elicited using the EQ-5D-5L questionnaire. ANOVA and bivariable analyses were conducted to identify differences between health states.

Using the bibliographic databases NSH EED and CEA Registry, we conducted searches of model-based cost utilities analyses of technologies in KOA or HOA patients. Health states and utilities were extracted and compared with values obtained from the Spanish sample.

Three hundred ninety-seven subjects with KOA and 361 subjects with HOA were included, with average utilities of 0.544 and 0.520, respectively. In both samples, differences were found in utilities according to level of pain, stiffness and physical function (WOMAC) and severity of symptoms (Oxford scales), so that the worst the symptoms, the lower the utilities. The utilities after surgery were higher than before surgery. Due to limitations from our study related to sample size and observational design, it was not possible to estimate utilities for approximately half the health states included in the published models because they were directly related to specific technologies. For almost 100% of health states of the selected studies we obtained very different utilities from those reported in the literature.

To our knowledge this is the first article with detailed utilities estimated using the EQ-5D-5L in Spain for KOA and HOA patients. In both populations, utilities are lower for worse health states in terms of level of pain, stiffness and physical function according to WOMAC, and according to the Oxford scales. Most utilities obtained from the Spanish sample are lower than those reported in the international literature. Further studies estimating utilities from local populations are required to avoid the use of foreign sources in economic evaluations.