Preference-based scoring algorithm to estimate societal utilities based on the patient-reported experience of cognitive impairment in schizophrenia (PRECIS) instrument
摘要
Generic measures of health-related quality of life (HRQoL), such as the EQ-5D, may inadequately capture the impact of cognitive impairment in schizophrenia, resulting in incorrect QALY estimates in economic evaluations. This study aimed to obtain health utilities by valuing key items of the Patient-Reported Experience of Cognitive Impairment in Schizophrenia (PRECIS) instrument.
MethodsFirst, expert interviews and psychometric analysis of the 28-item version of the PRECIS were performed to identify the best-performing and most relevant items. Second, health states based on the four selected PRECIS items representing memory, communication, executive function and attention (each with five levels of severity) were valued by the UK general public through a discrete choice experiment (DCE) survey and composite time trade-off (cTTO) interviews. To estimate a utility scoring algorithm, the DCE data were analyzed using mixed logit models and rescaled onto a 0–1 (dead to full health) utility scale using the cTTO results.
ResultsThe cTTO utility for the best health state (level 1, “not at all hard”, across all domains) had a mean utility of 0.992 (SD 0.038) while the worst state (level 5, “very hard”, across domains) had a mean utility of 0.292 (SD 0.479). All domains significantly predicted larger utility decrements with increasing impairment severity.
ConclusionThis study demonstrated the feasibility of quantifying health utility values for patient-reported cognitive impairment domains using the validated PRECIS instrument. The resulting utilities can capture the HRQoL impact of cognitive impairment, supporting more accurate future economic evaluations of therapies targeting cognitive function in schizophrenia.