Seventeen RCTs were included (n=761 reported in text and n=855 in table). Sample size ranged from 17 to 168. Six studies reported adequate randomisation methods. Six studies were single-blinded. All studies reported reasons for withdrawals. Six studies reported allocation concealment.
Botulinum toxin injection versus pneumatic dilation treatments (five studies, n=154): Pneumatic dilation was associated with a significantly higher remission rate (66% versus 36%, RR 2.20, 95% CI 1.51 to 3.20) and significantly lower relapse rate (17% versus 50%, RR 0.36, 95% CI 0.22 to 0.58) than botulinum toxin injection. No significant heterogeneity was found for the clinical efficacy analysis.
Botulinum toxin injection versus laparoscopic myotomy (two studies, n=117): Laparoscopic myotomy was associated with "superior efficacy" at one year compared to botulinum toxin injection (83% versus 65%, RR 1.28, 95% CI 1.02 to 1.59).
Pneumatic dilatation versus laparoscopic myotomy (two studies, n=81 underwent these procedures): Laparoscopic myotomy was associated with significantly higher remission rates (95% versus 78% in first paragraph of text, 82% versus 65% in second paragraph of text and 95% versus 64% in forest plot, RR 1.48, 95% CI 1.16 to 1.87 in both text and forest plot) and a significantly lower relapse rate (5% versus 36% in first paragraph of text, 4% versus 23% in second paragraph of text, RR 0.14, 95% CI 0.04 to 0.58).
There were no differences in one-year remission rates between: nifedipine versus pneumatic dilation (one study, n=30); pneumatic dilation versus pneumatic dilation plus botulinum toxin injection (one study, n=54); or laparoscopic myotomy versus thoracic myotomy (one study, n=168).
Complications and adverse events: Pneumatic dilation treatments were associated with significantly higher complication rates than botulinum toxin injection (19% versus 5%, risk difference 0.15, 95% CI 0.03 to 0.25). The most severe complication was perforation. Thoracic myotomy was associated with a significantly higher rate of gastrointestinal reflux than laparoscopic myotomy (67% versus 17%, p<0.03; one study). Botulinum toxin injection was associated with dysphagia and chest pain. Pneumatic dilation and laparoscopic myotomy were associated with dysphagia and heartburn.