Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2007; 12: 50
To investigate the associations of different effect-size measures with global ratings of treatment effect/change in health status, with focus on short- vs. medium-term effects, patients’ vs. physicians’ rating, consistency over different outcomes, and dependency from pain condition.
This was a secondary analysis of an observational study on acupuncture in 5378 patients (mean (SD) age 54.9 ± 14.7 years; 82.8% female) with chronic headache, low back pain or osteoarthritic pain. Outcomes (at baseline, after last acupuncture session and 6 months after start of treatment) were intensity of pain, days with pain/intake of painkillers, pain-related disability, pain sensation, depression, QOL, functional ability for back pain, and WOMAC for osteoarthritis. Global treatment effect/change in health status was assessed at the end of treatment and 6 months after. Effect sizes were estimated as standardised response means.
Global ratings showed linear fit to effect-size measures for most outcomes. For example, effect sizes of 0.33 and 0.80 were estimated as relevant difference changes for WOMAC score. Patients’ ratings were more sensitive than physicians’ assessment. Standardised mean changes better represented global ratings than percentages with respect to baseline. Similar associations were found for short- and medium-term effects. With the exception of some pain-specific outcomes, associations in pain-related subgroups were comparable.
Definitions of clinically important differences must consider the kind of research question. A lot of factors impact on the appraisal of differences; thus, the determination of general thresholds is not reasonable.
