Coffee consumption and cardiovascular diseases and mortality in patients with type 2 diabetes: A systematic review and dose–response meta-analysis of cohort studies

Shahinfar H, Jayedi A, Khan TA, Shab-Bidar S · Nutrition, Metabolism and Cardiovascular Diseases · 2021 August

DOI 10.1016/j.numecd.2021.05.014

Objective

To investigate the long-term consequences of coffee drinking in patients with type 2 diabetes, focusing on the association with cardiovascular disease (CVD) and mortality.

Conclusions

Coffee consumption, particularly at 4 cups per day, was inversely associated with all-cause mortality (HR: 0.79), CVD mortality (HR: 0.60), coronary heart disease (CHD) mortality (HR: 0.68), CHD events (HR: 0.72), and total CVD events (HR: 0.77) in patients with type 2 diabetes. No significant associations were found for cancer mortality and stroke. The certainty of evidence was moderate for all-cause mortality and low or very low for other outcomes.

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Insights

Drinking coffee may be linked to lower mortality risk in type 2 diabetes patients.

In this study, the researchers conducted an exhaustive literature search through PubMed, Scopus, and Web of Sciences up to November 2020. They were looking for prospective cohort studies that evaluated the link between coffee consumption and the risk of cardiovascular disease and mortality in patients with type 2 diabetes. Two reviewers took on the work of extracting relevant data and assessing the certainty of evidence using the GRADE approach. A random-effects model was deployed to estimate hazard ratios. Dose-response connections were modeled using a one-stage mixed-effects meta-analysis. The researchers included ten prospective cohort studies that totalled 82,270 cases. The results showed an interesting trend: compared to those who did not consume coffee, the hazard ratios were consistently lower for mortality outcomes and cardiovascular disease, especially where the consumption rate was four cups per day. Importantly, no such association was found for either cancer mortality or stroke. The evidence suggested a potential inverse monotonic association between coffee drinking and mortality across all causes and cardiovascular disease, alongside a linear association for coronary heart disease and total cardiovascular events. The degree of certainty in these results was moderate for all-cause mortality, but was low or very low for all other reported outcomes.