Hidden link in gut–joint axis: gut microbes promote rheumatoid arthritis at early stage by enhancing ascorbate degradation

Characteristic (%) Before PS adjustment After PS adjustment Before PS adjustment After PS adjustment PPI (n=1 01 438) Non-PPI (n=3 53 266) SMD PPI (n=11 741) Non-PPI (n=11 741) SMD PPI (n=10 708) H 2 RA (n=1 19 493) SMD PPI (n=5067) H 2 RA (n=5067) SMD Values are presented as proportion of the patients (%).*The applicated raw database was the National Health Insurance Service Common Data Model.GORD, gastro-oesophageal reflux disease; H2RA, histamine 2 receptor antagonist; PPI, proton pump inhibitor; PS, propensity matching; SMD, standard mean difference.Table 1 Continued last day of the eradication treatment as the index date.While the authors have mentioned in the discussion section that they could not determine H. Pylori infection status by a laboratory test, it is important to know if both groups were matched regarding clarithromycin based triple therapy or bismuth-based quadruple therapy, as they might differ in efficacy considering 20% resistance rate to clarithromycin in Korea. 2 The authors also mentioned a cumulative dose-response relationship between increasing PPI duration and the risk of gastric cancer development.Though it is true for PPI≥30 and≥180 days, the same is not true for PPI≥365 days, as the result was not statistically significant (PPI≥365 days, HR 3.5, 95% CI 0.85 to 23.49, p value 0.14).Summarily, the gastric cancer incidence rate is higher in Korean men than women when we compare ≥40 years of age groups.3 Hence, it is important to know if gender was equally distributed for each age range in table 1.Our concern is if the PPI group had more men in ≥40 years age group, it can skew the result in the favour of PPI.