3099 — The Quality of Well-Being Scale is Sensitive to Changes in PTSD Symptoms

Siroka AM (Health Economics Resource Center), Chen S (Health Economics Resource Center), Smith MW (Health Economics Resource Center), Baker DG (VA San Diego Health Care System), Saxon A (VA Puget Sound Health Care System), McFall M (VA Puget Sound Health Care System)

Objectives:
In VA there is a growing need for health-related quality-of-life (HRQoL) instruments that are sensitive to changes in PTSD symptoms and, hence, can reflect gains from mental health treatment. The objective of this study was to determine the sensitivity of the Quality of Well-Being Scale (QWB), a widely used measure of HRQoL, to variation in PTSD symptoms in a veteran population.

Methods:
The data were derived from a clinical trial at 10 VA medical centers. All participants were receiving outpatient PTSD therapy through VA. The data came from surveys administered at enrollment. The CAPS (Clinician-Administered PTSD Scale) was used to measure symptom severity in each of the three clusters that define PTSD: intrusive thoughts (criteria B), avoidance and numbing (criteria C), and hypervigilance (criteria D). The Quality of Well-Being Scale (QWB) measured HRQoL, also called “utility.” Scores range from 0.0 (death) to 1.0 (perfect health). Descriptive statistics and correlations across scales were calculated in SAS v.10. Chi-square tests were used to determine statistical significance.

Results:
Full data were available for 940 participants. They were 54 years old on average; 58% were White, 37% were Black/African-American, and 5% were of other races; 94% were male. CAPS total scores fell in the moderate-to-severe range: mean = 75, s.d. = 18, range 27-122. Scores over 65 are considered moderately severe or severe. The mean QWB score at baseline was 0.48, a very low score similar to that of people with severe Alzheimers disease. The Quality of Well-Being Scale (QWB) was sensitive to changes in PTSD symptoms. In most cases there was a drop of 0.025 or more in QWB for each 10-point increase in CAPS score, the minimum clinically meaningful difference. The correlation of QWB to CAPS scores were -.184 for B criteria, -.218 for C, -.217 for D, and -.254 for the CAPS total score (B+C+D); all were highly significant (p < .001).

Implications:
Among people receiving outpatient VA treatment for PTSD, the QWB is sensitive to clinically meaningful changes in PTSD symptoms as measured by the CAPS. The QWB can be used with confidence to measure HRQoL (utility) in health services and health economic studies of treatments for PTSD in veterans.

Impacts:
VA clinicians will benefit from accurate measurement of HRQoL among their patients. VA managers will gain from reliable assessments of cost-effectiveness and other outcomes that rely on HRQoL.