Meta-analysis of clinical outcome after treatment for achalasia based on manometric subtypes

Background: The introduction of high-resolution manometry and the Chicago classification has made it possible to diagnose achalasia and predict treatment response accurately. The aim of this study was to compare the effect of the different treatments available on symptomatic outcomes across all achalasia subtypes. Methods: The study was conducted according to PRISMA and MOOSE guidelines. A literature search of PubMed and MEDLINE databases was undertaken to identify all relevant articles reporting clinical outcomes of patients with achalasia after botulinum toxin injection, pneumatic dilatation, laparoscopic Heller myotomy (LHM) and peroral endoscopic myotomy (POEM) based on manometric subtypes. Patients were grouped according to the Chicago classification and the success rate in treating symptoms was measured as the primary endpoint. Results: Twenty studies (1575 patients) were selected, and data on botulinum toxin, pneumatic dilatation, LHM and POEM were extracted. Success rates for LHM in type I, II and III achalasia were 81, 92 and 71 per cent respectively. Those for POEM were 95, 97 and 93 per cent respectively. POEM was more likely to be successful than LHM for both type I (odds ratio (OR) 2.97, 95 per cent c.i. 1.09 to 8.03; P = 0.032) and type III (OR 3.50, 1.39 to 8.77; P = 0.007) achalasia. The likelihood of success of POEM and LHM for type II achalasia was similar. Conclusion: Pneumatic dilatation had a lower but still acceptable success rate compared with POEM or LHM in patients with type II achalasia. POEM is an excellent treatment modality for type I and type III achalasia, although it did not show any superiority over LHM for type II achalasia.