Controlled trials of therapy in fibromyalgia (FM) syndrome

Many different interventions have been studied in the therapy of

fibromyalgia syndrome (Tables 1 and 2). While most have been

effective, in general these trials have been short term.

Furthermore, important or substantial improvement, when it has

been assessed, occurs in only small proportions of patients.

Long-term, comparative trials of both efficacy and toxicity

are necessary. Trials such as these require large numbers of

patients (compared with placebo-controlled trials, which are

generally impractical in long-duration trials due to the large

numbers of dropouts in the placebo arm) and therefore are

expensive and difficult to accomplish. Two other approaches

offer potential solutions to the problem of adequate long-term

comparative trials: (a) N-of-1 trials and (b) meta-analysis.

N-of-1 trials have the advantage of random assignment,

double-blinding and multiple potential comparisons in the same

patient. Meta-analysis involves combining the results of

studies, which individually may have conflicting results and

lack adequate statistical power, to reach an overall result

with sufficient statistical power to make meaningful

conclusions, especially with respect to comparative efficacy.

Peluso and colleagues (1993) have performed a recent

meta-analysis of available therapies in fibromyalgia syndrome

and found that the effect-size (a standardized measure of the

efficacy of a given therapy) of several non-medication

therapies such as electroacupuncture exceeded that of

traditional medication therapies. Unfortunately, lack of

uniformity in the use of outcome measures across included

trials and the small numbers of comparable non-medication

trials makes definitive conclusions regarding relative

efficacy of therapies difficult. Nevertheless, application of

meta-analytic methods such as these should facilitate future

comparisons of different interventions. Ideally, future

clinical trials in fibromyalgia syndrome should employ the

same outcome measures to permit application of these methods.

Few trials have assessed improvement in functional status.

Functional status measures such as the HAQ (Fries et al.,

1980), the Fibromyalgia Impact Questionnaire (Burckhardt et

al, 1991) or similar instruments should be employed in future

studies of therapy in fibromyalgia. Given that individual

modalities appear to confer relatively modest benefit on

average. Combination approaches are reasonable, although

randomized, blinded trials to assess these approaches are

methodologically complex. Several preliminary studies which

have addressed this approach appear promising (see Chapter 12;

Goldenberg et al, 1993). Finally, no studies have yet assessed

the comparative cost-efficacy of available treatments.

Controlled trials which address the cost-efficacy of commonly

employed, but unproven treatments such as physiotherapy

chiropractic manipulation and injection techniques are

urgently needed.

Simms RW

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