Use of hydrochlorothiazide and risk of skin cancer: a nationwide Taiwanese case–control study

Background: The antihypertensive agent hydrochlorothiazide has been associated with increased risks of non-melanoma skin cancer (NMSC) and possibly some melanoma subtypes. Previous studies were, however, conducted in predominantly Caucasian populations. We therefore examined the association between hydrochlorothiazide and skin cancer risk in an Asian population. Methods: By using Taiwan’s National Health Insurance Research Database (NHIRD), we conducted three separate case–control studies of lip cancer, non-lip non-melanoma skin cancer and melanoma. Cases (n = 29,082) with a first-ever skin cancer diagnoses (2008–2015) were matched 1:10 to population controls. We estimated odds ratios (ORs) associating hydrochlorothiazide use with skin cancer risk by using conditional logistic regression. Results: Hydrochlorothiazide use showed no overall association with any of the three outcomes: ORs for high cumulative use of HCTZ (≥50,000 mg) were 0.86 (95% CI 0.09–7.81) for lip cancer, 1.16 (95% CI 0.98–1.37) for non-lip NMSC and 1.07 (95% CI 0.65–1.76) for melanoma. There was some evidence of a dose–response pattern for non-lip NMSC, with an OR of 1.66 (95% CI 0.82–3.33) for 100,000–149,999 mg of HCTZ. The null findings were robust across subgroup and sensitivity analyses. Conclusion: Use of HCTZ appears safe in terms of skin cancer risk in an Asian population.