We read with interest the study by Hong et al. [1] in which they showed that hypertension and polypharmacy were significantly associated with constipation in people with obesity. In particular, hypertension was associated with a reduced risk of constipation. While the findings are interesting, we would like to highlight some key confounding variables that the authors have not raised or taken into consideration in their study.

First, no data on the use of laxatives and other medications (such as opioid analgesics) were presented. In particular, nonprescriptive laxatives are widely used and have a major impact on stool consistency or frequency and are known major confounders on the assessment of constipation. Furthermore, one of the objective outcomes for capturing the actual clinical impact or validation of diagnosis will be the number of hospitalizations for constipation and the duration of stay [2]. It will be interesting if these data have been collected for analysis.

Second, the use of polypharmacy (>5 drugs) as an independent variable is problematic as this does not differentiate between the use of a single drug that can have a potent impact on gut motility and the collective use of several drugs at the same time that have little effect. We think analysis based on the specific class of drugs will be more useful than the number of medications.

Third, the classification of hypertension used in the study with a cross sectional design can lead to an inaccurate capture as many asymptomatic cases may be missed or subjects may be erroneously diagnosed based on limited pressure readings. Due to these mentioned limitations, we would advise cautious interpretation of the finding that hypertension and polypharmacy are associated with constipation in people with obesity. A prospective longitudinal study with objective measurements of constipation and obesity to further investigate the exact cause and effect relationship will provide more conclusive evidence.

The authors have no conflicts of interest to declare, except E.-K.T. has received honoraria for academic activity from Eisai.

We thank National Medical Research Council and Duke-NUS Medical School for their support. The funders had no role in the design, data collection, data analysis, and reporting of this study.

B.J.-W.T. and E.-K.T. drafted the manuscript, and Z.-D.Z. and L.-L.C. contributed to the final draft. All authors above approved the final version.

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