HOW SHOULD WE EVALUATE HEALTH-STATUS - A COMPARISON OF 3 METHODS IN PATIENTS PRESENTING WITH OBSTRUCTIVE SLEEP-APNEA

The purpose of this paper is to compare three approaches to the measur ement of patient-reported health status which produce summary scales o f health status: the Patient-generated Index (PGI) is a measure of ind ividual quality of life (QoL), the EuroQol is a measure of QoL the res ults of which are weighted by utility values gained from community sur veys and the SF-36 which produces two summary scales of health status (the physical component summary (PCS) and the mental component summary (MCS) scores). A follow-up interview survey of patients with obstruct ive sleep apnoea (OSA) was conducted. The patients received continuous positive airways pressure therapy (CPAP) between the two administrati ons of the questionnaires. One hundred patients presenting with OSA an d who were suitable for CPAP therapy were asked if they would take par t in the study. The results on the PGI, EuroQol EQ-5D utility weighted scores and 'thermometer' scores and SF-36 physical and mental summary scores were measured. Eighty-nine respondents provided sufficient dat a to calculate PGI and EuroQol scores and 86 patients provided suffici ent data to calculate SF-36 summary scores. The PGI indicated substant ial improvement after CPAP treatment whereas the EuroQol indicated lit tle or no improvement on either utility weighted or thermometer scores . The SF-36 PCS and MCS scores were lower than those of the general po pulation at baseline, but had improved to the normative levels after t reatment. The EuroQol provided a substantially different picture of ch ange to either of the ones gained from the SF-36 or PGI. It is suggest ed that the EuroQol does not contain questions which relate to importa nt aspects of health and well-being and may not accurately reflect the health state of individuals. Consequently, caution must be exercised to assure that an appropriate instrument has been employed when using health outcomes data to assess or prioritize available health care tre atments.