A Cochrane review [Abstract] 1 included 17 studies with a total of 1025 subjects with vertigo. They had clinically defined Ménière's disease (5 studies), episodic vertigo (3 studies), benign paroxysmal positional vertigo (BPPV, 2 studies) or chronic vertigo (one study); the rest of the studies had a mixed population. All studies lasted 3 months or less. Pooled data showed that the proportion of patients reporting an overall reduction in their vertigo symptoms was higher for the betahistine than for the placebo group (RR 1.30, 95% CI 1.05 to 1.60; 11 studies, n=606). There was no difference in the frequency of adverse effects between the betahistine and placebo groups (16% and 15%, respectively, RR 1.03, 95% CI 0.76 to 1.40; 12 studies, n=819).A total of 16% of patients from both the betahistine and the placebo groups withdrew from the studies (RR 0.96, 95% CI 0.65 to 1.42; 8 studies, n=481).
A meta-analysis 1 included 12 double-blind, randomized, placebo-controlled clinical studies with betahistine in patients suffering from vestibular vertigo or Ménière's disease. The clinical endpoint was the investigator's overall opinion on the response to treatment of the vertigo symptoms, after at least 1 month of treatment. The odds of a favorable treatment outcome was used as effect parameter, with the odds ratio as measure to compare the responses of betahistine and placebo patients. For each study a separate odds ratio was estimated (the study-specific odds ratio). All but one of the study-specific odds ratios were >1.0, meaning that there was evidence of an effect of betahistine on vertigo symptoms in 11 of the 12 studies. Four of the 12 studies showed a statistically significant effect in favor of betahistine compared to placebo. The meta-analytical OR was 2.58 (95 % Cl 1.67 to 3.99). Sub-analyses conducted for patients with Ménière's disease on one hand and with vestibular vertigo on the other hand also yielded statistically significant results. For Ménière's disease, the OR was 3.37 (95 % CI 2.14 to 5.29); for vestibular vertigo, the OR was 2.23 (95 % CI 1.20 to 4.14).
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in patients, interventions and outcomes) and indirectness (short follow-up time).
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