Increased interleukin‐6 is associated with higher risk of heart failure in people with type 2 diabetes

Abstract Aims We aimed to determine the association between serum interleukin‐6 (IL‐6) concentrations and new‐onset heart failure (HF) in persons with type 2 diabetes (T2D). Methods and results We performed a case–control study nested in the Diabetes Care System Cohort, a prospective cohort of persons with T2D in primary care. We included 724 participants, of whom 141 developed HF during 5 years of follow‐up and 583 were age‐ and sex‐matched controls. IL‐6 was measured at baseline and categorized into four groups: Group 1 was composed of participants with IL‐6 below the detection limit of 1.5 pg/mL, and the remainder were divided into tertiles. We performed logistic regression analyses with categorized IL‐6 or continuous IL‐6 as the determinant and new‐onset HF as the outcome adjusted for follow‐up time, age, sex, glycated haemoglobin, estimated glomerular filtration rate, albumin/creatinine ratio, and cardiovascular disease at baseline. Effect modification by sex was tested. Participants were 70.7 ± 9.0 years, and 38% were women. In comparison with Group 1, all tertiles were associated with an increased risk of HF with odds ratios of 2.1 [95% confidence interval (CI): 1.2–2.9], 2.8 (95% CI: 2.0–3.7), and 2.1 (95% CI: 1.3–3.0), respectively, for Tertiles 1–3. Continuous IL‐6 was associated with the development of HF with an odds ratio of 1.2 (95% CI: 1.0–1.5). No effect modification by sex was observed. Conclusions Higher IL‐6 levels are associated with the development of HF in persons with T2D. Further research should determine whether IL‐6‐lowering interventions could prevent the development of HF.