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.
Diabetes Metab. 2017 Oct;43(5):438-445. doi: 10.1016/j.diabet.2017.03.004. Epub 2017 Apr 21.
The association between metformin and colorectal cancer (CRC) has rarely been investigated in Asian populations.
This retrospective cohort study included patients with newly diagnosed type 2 diabetes during 1999-2005, recruited from Taiwan's National Health Insurance database. A total of 169,601 patients (original cohort: 153,270 ever-users and 16,331 never-users of metformin) and a subgroup of 1:1 propensity-score-matched pairs of 16,331 ever-users and 16,331 never-users (matched cohort) were followed up to 31 December 2011. Cox regression was constructed with the inverse probability of treatment-weighting, using propensity scores, and was used to estimate hazard ratios (HRs).
In the original cohort, the incidence of CRC was 242.9 and 480.9 per 100,000 person-years, respectively, in ever- and never-users. The overall HR [0.50, 95% confidence interval (CI): 0.45-0.56] suggested a significantly lower risk in metformin users, while compared with never-users, the HR (95% CI) for the first (<27.1 months), second (27.1-58.1 months) and third (>58.1 months) tertiles of cumulative duration of metformin therapy was 0.86 (0.76-0.98), 0.51 (0.45-0.59) and 0.26 (0.23-0.30), respectively. Analyses in the matched cohort showed similar findings with an overall HR of 0.62 (0.53-0.74), and a tertile analysis HR of 1.02 (0.81-1.28), 0.70 (0.56-0.89) and 0.32 (0.23-0.43), respectively. Re-analyses using more stringent diagnoses of CRC and cumulative duration as a continuous variable have consistently supported a protective effect with metformin use.
Metformin is associated with a lower frequency of CRC.
二甲双胍与结直肠癌（CRC）之间的关联在亚洲人群中很少被研究。
这项回顾性队列研究纳入了 1999 年至 2005 年期间新诊断为 2 型糖尿病的患者，这些患者均来自台湾的全民健康保险数据库。共有 169601 名患者（原始队列：153270 名二甲双胍既往使用者和 16331 名从未使用者）和 16331 名二甲双胍既往使用者和 16331 名从未使用者的 1:1 倾向评分匹配对亚组（匹配队列）被随访至 2011 年 12 月 31 日。使用倾向评分的逆概率治疗加权法构建 Cox 回归，并用于估计风险比（HRs）。
在原始队列中，二甲双胍既往使用者和从未使用者的 CRC 发生率分别为 242.9 和 480.9/100000 人年。总体 HR[0.50，95%置信区间（CI）：0.45-0.56]表明二甲双胍使用者的风险显著降低，而与从未使用者相比，累积使用二甲双胍治疗时间的第一个（<27.1 个月）、第二个（27.1-58.1 个月）和第三个（>58.1 个月）三分位的 HR（95%CI）分别为 0.86（0.76-0.98）、0.51（0.45-0.59）和 0.26（0.23-0.30）。匹配队列的分析结果相似，总体 HR 为 0.62（0.53-0.74），三分位分析 HR 为 1.02（0.81-1.28）、0.70（0.56-0.89）和 0.32（0.23-0.43）。使用更严格的 CRC 诊断和累积持续时间作为连续变量的重新分析一致支持二甲双胍使用的保护作用。
二甲双胍与 CRC 发生率降低有关。
