RESUMEN
BACKGROUND AND HYPOTHESIS: Schizophrenia is a severe mental disorder that has a significant impact on quality of life (QOL). Measuring QOL can offer insights into treatment efficacy and areas of intervention, highlighting the importance of valid tools assessing QOL in people with schizophrenia. STUDY DESIGN: We employed the COSMIN systematic review guideline to assess the psychometric properties of the schizophrenia quality of life scale (SQLS) and its 4th revision, the schizophrenia quality of life scale revision 4 (SQLS-R4), as patient-reported outcome measures (PROMs). STUDY RESULTS: The search yielded 455 papers, 16 were included, 7 for the SQLS and 9 for the SQLS-R4. Both scales demonstrated good results in risk of bias assessment for internal consistency and convergent validity, the SQLS-R4 additionally for known-groups validity. For the SQLS, PROM development, structural validity, and reliability were suboptimal. The SQLS-R4 showed suboptimality regarding structural validity and reliability and inadequacy for cross-cultural validity and responsiveness. The updated criteria for good measurement properties indicated good convergent validity for the SQLS and good internal consistency, reliability, and convergent validity for the SQLS-R4. The SQLS showed suboptimal results for reliability and known-groups validity, while the SQLS-R4 demonstrated suboptimality in structural validity and known-groups validity. The SQLS had indeterminate structural validity and internal consistency; the SQLS-R4 showed indeterminate responsiveness, and insufficient cross-cultural validity. When using the updated GRADE approach of the COSMIN group, both scales received a very low grade. CONCLUSIONS: The SQLS and SQLS-R4 hold the potential for recommendation in rating QOL. Identified weaknesses necessitate further validations.
RESUMEN
BACKGROUND AND HYPOTHESIS: Negative symptoms are very important for the overall loss of functioning observed in patients with schizophrenia. There is a need for valid tools to assess these symptoms. STUDY DESIGN: We used the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) systematic review guideline to evaluate the quality of the clinical assessment interview for negative symptoms (CAINS) as a clinician-rated outcome measurement (ClinROM). STUDY RESULTS: The search strategy resulted in the retrieval of 13 articles, 11 of which were included in this evaluation. In terms of risk of bias, most articles reported on measures of internal consistency and construct validity, which were overall of good quality. Structural validity, reliability, measurement error, and cross-cultural validity were reported with less than optimum quality. There was a risk of bias in ClinROM development. According to the updated criteria of good measurement properties, structural validity, internal consistency, and reliability showed good results. In contrast, hypothesis testing was somewhat poorer. Results for cross-cultural validity were indeterminate. According to the updated GRADE approach from the COSMIN group the scale received a moderate grade. CONCLUSIONS: The COSMIN standard allows a judgment of the CAINS as an instrument with the potential to be recommended for use, but which requires further research to assess its quality, in particular in the domains of content validity, internal consistency, and cross-cultural validity.
RESUMEN
BACKGROUND: Negative symptoms of schizophrenia are linked with poor functioning and quality of life. Therefore, appropriate measurement tools to assess negative symptoms are needed. The NIMH-MATRICS Consensus defined five domains for negative symptoms, which The Brief Negative Symptom Scale (BNSS) covers. METHODS: We used the COSMIN guidelines for systematic reviews to evaluate the quality of psychometric data of the BNSS scale as a Clinician-Rated Outcome Measure (ClinROM). RESULTS: The search strategy resulted in the inclusion of 17 articles. When using the risk of bias checklist, there was a generally good quality in reporting of structural validity and hypothesis testing. Internal consistency, reliability and cross-cultural validity were of poorer quality. ClinROM development and content validity showed inadequate results. According to the updated criteria of good measurement properties, structural validity, internal consistency and interrater reliability showed good results, while hypothesis testing showed poorer results. Cross-cultural validity and test-retest reliability were indeterminate. The updated GRADE approach resulted in a moderate grade. CONCLUSIONS: We can potentially recommend the use of the BNSS as a concise tool to rate negative symptoms. Due to weaknesses in certain domains further validations are warranted.