The impact of patient expectations on outcomes in four... : PAIN (original) (raw)

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The impact of patient expectations on outcomes in four randomized controlled trials of acupuncture in patients with chronic pain

Linde, Klausa,*; Witt, Claudia M.b; Streng, Andreaa; Weidenhammer, Wolfganga; Wagenpfeil, Stefanc; Brinkhaus, Bennob; Willich, Stefan N.b; Melchart, Dietera,d

a_Centre for Complementary Medicine Research, Department of Internal Medicine II, Technische Universität München, Kaiserstr. 9, 80801 Munich, Germany_

b_Institute of Social Medicine, Epidemiology, and Health Economics, Charité University Medical Centre, Berlin, Germany_

c_Institute of Medical Statistics and Epidemiology, Technische Universität München, Munich, Germany_

d_Division of Complementary Medicine, Department of Internal Medicine, University Hospital Zurich, Switzerland_

*Corresponding author. Tel.: +49 89 3304104 13; fax: +49 89 3304104 16.

E-mail: [email protected]

Submitted June 27, 2006; revised November 14, 2006; accepted December 4, 2006.

Abstract

In a pooled analysis of four randomized controlled trials of acupuncture in patients with migraine, tension-type headache, chronic low back pain, and osteoarthritis of the knee we investigated the influence of expectations on clinical outcome. The 864 patients included in the analysis received either 12 sessions of acupuncture or minimal (i.e. sham) acupuncture (superficial needling of non-acupuncture points) over an 8 week period. Patients were asked at baseline whether they considered acupuncture to be an effective therapy in general and what they personally expected from the treatment. After three acupuncture sessions patients were asked how confident they were that they would benefit from the treatment strategy they were receiving. Patients were classified as responders if the respective main outcome measure improved by at least fifty percent. Both univariate and multivariate analyses adjusted for potential confounders (such as condition, intervention group, age, sex, duration of complaints, etc.) consistently showed a significant influence of attitudes and expectations on outcome. After completion of treatment, the odds ratio for response between patients considering acupuncture an effective or highly effective therapy and patients who were more sceptical was 1.67 (95% confidence interval 1.20–2.32). For personal expectations and confidence after the third session, odds ratios were 2.03 (1.26–3.26) and 2.35 (1.68–3.30), respectively. Results from the 6-month follow-up were similar. In conclusion, in our trials a significant association was shown between better improvement and higher outcome expectations.