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Abstract title: Sensitivity of Generic Effectiveness Measures to Changes in Schizophrenia Symptom Severity

Author(s):
JM Pyne - Central Arkansas Veterans Healthcare System
G Sullivan - Central Arkansas Veterans Healthcare System
RM Kaplan - University of California San Diego
DK Williams - University of Arkansas for Medical Sciences

Objectives: To compare the sensitivity of four generic effectiveness measures to clinically meaningful symptom improvement in persons with schizophrenia.

Methods: The study included baseline and 6-month interviews with 134 subjects diagnosed with schizophrenia or schizoaffective disorder. The design was observational. The order of effectiveness measure administration was randomized. Separate interviewers collected effectiveness and symptom data. The four generic effectiveness measures included the Quality of Well-Being scale (QWB), a quality-adjusted index score based on the SF-36 (SF-36VAS), the mental health component summary score (MCS) from the VA-adapted SF-36, and the World Health Organization Disablement Assessment Schedule (WHODAS). Symptom measures included the Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale (CDS). Side effect measures included the Extrapyramidal Symptom Rating Scale (ESRS). Patient acceptability of the scales was also measured. Data analysis included correlations between symptom, side effect, and generic effectiveness change scores; a power calculation to detect a clinically significant 20% improvement in the total PANSS, and t-tests to compare patient acceptability.

Results: All effectiveness measures were correlated with changes in side effects. All but the SF-36VAS were correlated with changes in depression. Only the QWB was correlated with changes in PANSS scores. The QWB required less than one-third the subjects (n=61) needed to detect a clinically significant improvement in total PANSS compared to the other generic effectiveness measures (n=201 to 324). The QWB was also more acceptable to patients.

Conclusions: We recommend that VA clinicians, administrators, and researchers use the QWB to demonstrate the effectiveness and cost-effectiveness of schizophrenia interventions. The QWB also allows for the direct comparison of the effectiveness and cost-effectiveness of schizophrenia interventions with other mental health and physical health interventions.

Impact statement: Use of QWB may contribute to a more efficient use of VA healthcare resources and a greater recognition of the value associated with mental health interventions.