Chin-Hsiao Tseng1. 1. Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan; Division of Endocrinology and Metabolism, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; Division of Environmental Health and Occupational Medicine of the National Health Research Institutes, Zhunan, Taiwan. Electronic address: ccktsh@ms6.hinet.net.
Abstract
BACKGROUND: Metformin, an antidiabetic drug, is associated with decreased cancer risk, but its effect on skin cancer is unknown. OBJECTIVE: To evaluate skin cancer risk associated with metformin use. METHODS: In total, 16,237 matched pairs of ever and never metformin users with new-onset type 2 diabetes diagnosed during 1999-2005 were retrospectively enrolled and followed until December 31, 2011, using Taiwan's National Health Insurance database. Hazard ratios (HRs) were estimated using Cox regression weighted for propensity scores. RESULTS: Skin cancer incidence was 45.59 and 83.90 per 100,000 person-years among ever and never users, respectively (HR 0.540, 95% confidence interval [CI] 0.357-0.819). Among ever users, the HRs (95% CIs) for the first (<21.00 months), second (21.00-45.83 months), and third (>45.83 months) cumulative duration tertiles were 0.817 (0.448-1.489), 0.844 (0.504-1.412), and 0.114 (0.036-0.364), respectively, and the HRs (95% CIs) for the first, second, and third cumulative dose tertiles were 1.006 (0.579-1.748), 0.578 (0.317-1.051), and 0.229 (0.099-0.530), respectively. HRs (95% CIs) were 0.523 (0.175-1.562) for melanoma and 0.496 (0.319-0.772) for nonmelanoma skin cancer. LIMITATIONS: Few patients had skin cancer and information on ultraviolet light exposure and tumor histopathology was lacking. CONCLUSION: Metformin use is associated with a decreased skin cancer risk.
BACKGROUND:Metformin, an antidiabetic drug, is associated with decreased cancer risk, but its effect on skin cancer is unknown. OBJECTIVE: To evaluate skin cancer risk associated with metformin use. METHODS: In total, 16,237 matched pairs of ever and never metformin users with new-onset type 2 diabetes diagnosed during 1999-2005 were retrospectively enrolled and followed until December 31, 2011, using Taiwan's National Health Insurance database. Hazard ratios (HRs) were estimated using Cox regression weighted for propensity scores. RESULTS:Skin cancer incidence was 45.59 and 83.90 per 100,000 person-years among ever and never users, respectively (HR 0.540, 95% confidence interval [CI] 0.357-0.819). Among ever users, the HRs (95% CIs) for the first (<21.00 months), second (21.00-45.83 months), and third (>45.83 months) cumulative duration tertiles were 0.817 (0.448-1.489), 0.844 (0.504-1.412), and 0.114 (0.036-0.364), respectively, and the HRs (95% CIs) for the first, second, and third cumulative dose tertiles were 1.006 (0.579-1.748), 0.578 (0.317-1.051), and 0.229 (0.099-0.530), respectively. HRs (95% CIs) were 0.523 (0.175-1.562) for melanoma and 0.496 (0.319-0.772) for nonmelanoma skin cancer. LIMITATIONS: Few patients had skin cancer and information on ultraviolet light exposure and tumor histopathology was lacking. CONCLUSION:Metformin use is associated with a decreased skin cancer risk.
Authors: Adarsh Ravishankar; Tianshun Zhang; Bruce R Lindgren; Ronda S Farah; Zigang Dong; Noah I Goldfarb Journal: Int J Dermatol Date: 2020-03-11 Impact factor: 2.736