Development and Psychometric Properties Evaluation of the Patient-Reported Outcome Measure for People With...

Given the paucity of appropriate patient-reported outcome measure (PROM) to assess the multidimensional rehabilitation status of people with schizophrenia in day rehabilitation centres (DRCs) in China, the present study aimed to develop a PROM specifically designed for people with schizophrenia in DRCs (SDRC-PROM) and evaluate its psychometric properties.

The development process of the SDRC-PROM was in accordance with the guideline established by the US Food and Drug Administration and the guideline outlined in the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist. Participants with schizophrenia were recruited from six DRCs in Nanjing, China. The conceptual framework and item pool were determined through literature review, semistructured interview with 14 participants, and two rounds of Delphi method with 16 experts. The comprehensibility and feasibility of the measure were assessed through a pilot test with another 12 participants. Psychometric properties of the SDRC-PROM were evaluated in a formal survey containing 127 participants. The discrimination ability of items was estimated through the item analysis with the critical ratio, item-total correlation, corrected item-total correlation, Cronbach's α if item deleted, communality and factor loading. The construct validity was assessed through exploratory factor analysis (EFA). The internal consistency reliability, the test-retest reliability, measurement error and responsiveness were used to evaluate the reliability of the measure.

The final SDRC-PROM comprised four domains with 40 items. Delphi consultations showed acceptable degree of concentration and coordination of experts' opinions. There were 10 ineligible items deleted during the item analysis. EFA supported a four-domain construct related to the psychological, physiological, social and therapeutic domain, and four domains explained 70.7% of the total variance. The Cronbach's α coefficient of the overall measure was 0.911, which of the four domains ranged from 0.814 to 0.907. The intraclass correlation coefficient (ICC) of the measure was 0.902, that of four domains varied from 0.853 to 0.913. The SDRC-PROM also indicated acceptable measurement error based on the illustration of standard error of measure (SEM), and smallest detectable change (SDC). Meanwhile, the responsiveness was also confirmed by the less SDC than the minimum important change (MIC).

The SDRC-PROM is a reliable and valid measure with sufficient responsiveness to assess various aspects of rehabilitation status of people with schizophrenia from DRCs, which is conducive to optimising the evaluation system and ameliorating psychiatric rehabilitation care services for people with schizophrenia in DRCs in China.