Resting heart rate and cardiovascular outcomes in diabetic and non-diabetic individuals at high cardiovascular risk analysis from the ONTARGET/TRANSCEND trials
Authors: Böhm Michael , Schumacher Helmut , Teo Koon K , Lonn Eva M , Mahfoud Felix , Ukena Christian , Mann Johannes F E , Mancia Giuseppe , Redon Josep , Schmieder Roland E , Sliwa Karen , Marx Nikolaus , Weber Michael A , Williams Bryan , Yusuf Salim 
Published: November 2018

Abstract

Aims
Resting heart rate (RHR) has been shown to be associated with cardiovascular outcomes in various conditions. It is unknown whether different levels of RHR and different associations with cardiovascular outcomes occur in patients with or without diabetes, because the impact of autonomic neuropathy on vascular vulnerability might be stronger in diabetes.

Methods and results
We examined 30 937 patients aged 55 years or older with a history of or at high risk for cardiovascular disease and after myocardial infarction, stroke, or with proven peripheral vascular disease from the ONTARGET and TRANSCEND trials investigating ramipril, telmisartan, and their combination followed for a median of 56 months. We analysed the association of mean achieved RHR on-treatment with the primary composite outcome of cardiovascular death, myocardial infarction, stroke, hospitalization for heart failure, the components of the composite primary outcome, and all-cause death as continuous and categorical variables. Data were analysed by Cox regression analysis, ANOVA, and χ2 test. These trials were registered with ClinicalTrials.gov.number NCT00153101. Patients were recruited from 733 centres in 40 countries between 1 December 2001 and 31 July 2008 (ONTARGET) and 1 November 2001 until 30 May 2004 (TRANSCEND). In total, 19 450 patients without diabetes and 11 487 patients with diabetes were stratified by mean RHR. Patients with diabetes compared to no diabetes had higher RHRs (71.8 ± 9.0 vs. 67.9 ± 8.8, P &lt; 0.0001). In the categories of &lt;60 bpm, 60 ≤ 65 bpm, 65 ≤ 70 bpm, 70 ≤ 75 bpm, 75 ≤ 80 bpm and ≥80 bpm, non-diabetic patients had an increased hazard of the primary outcome with mean RHR of 75 ≤ 80 bpm (adjusted hazard ratio [HR] 1.17 (1.01–1.36)) compared to RHR 60 ≤ 65 bpm. For patients with in-trial RHR ≥80 bpm the hazard ratios were highest (diabetes: 1.96 (1.64–2.34), no diabetes: 1.73 (1.49–2.00), For cardiovascular death hazards were also clearly increased at RHR ≥80 bpm (diabetes [1.99, (1.53–2.58)], no diabetes [1.73 (1.38–2.16)]. Similar results were obtained for hospitalization for heart failure and all-cause death while the effect of RHR on myocardial infarction and stroke was less pronounced. Results were robust after adjusting for various risk indicators including beta-blocker use and atrial fibrillation. No significant association to harm was observed at lower RHR.

Conclusion
Mean RHR above 75–80 b.p.m. was associated with increased risk for cardiovascular outcomes except for stroke. Since in diabetes, high RHR is associated with higher absolute event numbers and patients have higher RHRs, this association might be of particular clinical importance in diabetes. These data suggest that RHR lowering in patients with RHRs above 75–80 b.p.m. needs to be studied in prospective trials to determine if it will reduce outcomes in diabetic and non-diabetic patients at high cardiovascular risk.

Clinical Trial registration
http://clinicaltrials.gov.Unique identifier: NCT00153101.