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Sirs,

A recent cohort study demonstrated that, after controlling for possible confounding factors, patients with chronic obstructive pulmonary disease (COPD) had a 1.9-fold risk of developing peptic ulcer bleeding (95% CI: 1.73–2.17).[1]

In contrast, in a case–control study using the UK-based General Practice Research Database, COPD was not associated with peptic ulcer (OR = 1.24, 95% CI = 0.92–1.66).[2] However, smoking and corticosteroid use, two well-established risk factors for peptic ulcer bleeding,[3] could not be completely addressed in Huang et al. study.

Smoking is a well-known risk factor for COPD, but the authors reported that approximately 25–45% of COPD patients never smoked.[4] However, the smoking prevalence is high in Taiwan (46.8% in men and 4.3% in women).[5] We therefore estimate the proportion of smokers to be about 25.7–35.1% among men with COPD in Huang et al. study. Because of an inherent limitation of Taiwan National Health Insurance database, smoking could not be included for further analysis.

Oral systemic or inhaled corticosteroids are commonly prescribed drugs for treating COPD patients. In this study, only 6.2% of COPD patients had ever used corticosteroids.[1] We think that this number could be underestimated, which may be why corticosteroid use did not reach statistical significance (HR = 1.06, 95% CI = 0.85–1.33).[1] Moreover, other treatments used could not be shown in over 90% of COPD patients in Huang et al. study.

Because of a lack of comprehensive data about smoking and corticosteroid use, whether COPD has an absolute effect on peptic ulcer bleeding or a relative effect mediated by smoking and corticosteroid use could not be determined. In our opinion, COPD could only be regarded as a comorbid condition at present, not a risk factor for peptic ulcer bleeding. Thus, more prospective studies with COPD subjects who do not smoke are required to definitively elucidate this issue.

Acknowledgement

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Declaration of personal and funding interests: None.

References

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  3. References