LAUSR

We read with great interest the meta-analysis by Vespa et al. [1] reporting the long-term outcomes of efficacy and safety of peroral endoscopic myotomy (POEM) for achalasia. The authors included 11 studies involving 2342 patients and concluded that the pooled clinical success rate was 87.3% and the pooled symptomatic reflux rate was 22.0%. We appreciate the authors’ hard work. However, we have several concerns about the study. First, it should be highlighted that the included studies by McKay et al. [2] and Mondragón et al. [3] did not match the predefined inclusion criteria in this meta-analysis, but were still included. The eligibility criteria specified that clinical success was defined as a post-POEM Eckardt score of ≤3. However, in studies conducted by McKay et al. [2] and Mondragón et al. [3], clinical success was defined as a post-POEM Eckardt score of < 3. Therefore, the inclusion of the two studies is arguable. Second, it should also be mentioned that the subgroup analyses did not address the high degree of heterogeneity in the analyses of the pooled clinical success rate and the pooled symptomatic reflux rate. Liu et al. [4] found that clinical failure and adverse events decreased after 100 cases, while the sample size of the 11 included studies ranged widely from 32 to 1538. Furthermore, the mean follow-up time of the 11 studies included was highly heterogeneous, spanning from 36 to 88 months. Ofosu et al. [5] carried out another meta-analysis of shortand mid-term outcomes of POEM, demonstrating a decline in clinical success rate over time. Therefore, additional subgroup analyses based on sample size and mean follow-up time should be conducted to establish the stability of the results. Even though this study had some shortcomings, it was the first meta-analysis to present the long-term clinical outcomes of POEM.