The association of metformin, other antidiabetic medications, and statins with the prognosis of colon cancer in patients with type 2 diabetes : a retrospective cohort study

Abstract

<div lang="en" class="abs"><p class="abs_header">Abstract</p><p><em>Background:</em> Use of metformin and statins have been associated with improved prognosis of colon cancer (CC) in patients with type 2 diabetes (T2D). We examined the survival from CC in relation to the use of metformin, other oral antidiabetic medications (ADM), insulin, and statins in T2D patients.</p><p><em>Materials and Methods:</em> A cohort (n = 2252) of persons with pre-existing T2D diagnosed with incident CC between 1998 and 2011 was identified from several Finnish registers. Cox models were fitted for cause-specific mortality rates to obtain adjusted estimates of the hazard ratios (HR) with 95% confidence intervals (CI) in relation to use of ADM and statins before the CC diagnosis. Cox models were also fitted for mortality in relation to post-diagnostic use of the medications treating these as time-dependent exposures, and starting follow-up 1 year after the CC diagnosis.</p><p><em>Results:</em> Pre- and post-diagnostic metformin use was weakly associated with the risk of CC-related death (HR 0.75; 95% CI 0.58–0.99, and HR 0.78; 95% CI 0.54–1.14, respectively) compared to the use of other oral ADMs. Pre- and post-diagnostic statin use predicted a reduced risk of CC-related death (HR 0.83; 95% CI 0.71– 0.98, and HR 0.69; 95% CI 0.54–0.89, respectively).</p><p><em>Conclusions:</em> Additional evidence was found for use of statins being associated with an improved survival from CC in patients with pre-existing T2D, but for metformin use the evidence was weaker.</p></div>