High Resting Heart Rate Linked to CV Event Risk in Patients With T2DM

A high resting heart rate (RHR) is associated with increased risk for cardiovascular events among patients with type 2 diabetes mellitus (T2DM) with diabetic retinopathy and without known cardiovascular disease, according to a study published in Hypertension Research.

Investigators conducted a subanalysis of data from the EMPATHY (Standard Versus Intensive Statin Therapy for Hypercholesterolemic Patients with Diabetic Retinopathy) study. In addition to T2DM with diabetic retinopathy, study participants had an elevated low-density lipoprotein cholesterol (LDL-C) level (≥120 mg/dL without lipid-lowering drugs or ≥100 mg/dL with lipid-lowering drugs). The median follow-up was 36.7 (IQR, 25.8-46.0) months.

Cardiovascular events were defined as the composite incidence of cardiac, cerebral, renal, and vascular events or death associated with cardiovascular events. Patients were categorized into 4 groups based on their baseline RHR (<60, 60-69, 70-79, and ≥80 bpm).

Of the patients included in the study (N=4746), 175 were in the RHR of less than 60 bpm group (mean age, 67.9 [SD, 8.5] years; 57.1% men); 1023 were in the RHR of 60 to 69 bpm group (mean age, 65.5 [SD, 9.4] years; 49.6% men); 1616 were in the RHR of 70 to 79 bpm group (mean age, 63.4 [SD, 10.3] years; 46.5% men); and 1932 were in the RHR of 80 bpm or more group (mean age, 61.0 [SD, 11.1] years; 47.0% men). Median RHR was 76 bpm (range, 39-131 bpm), with an IQR of 69 to 85 bpm.

Participants had 266 cardiovascular events, including 105 cardiac, 59 cerebral, 90 renal, and 12 vascular events. The cumulative incidence of cardiovascular events after adjustment for age, sex, and EMPATHY treatment allocation increased significantly among patients with an RHR of 80 bpm or more (P =.014) and tended to increase in those with an RHR of 70 to 79 bpm (P =.087) vs those who had an RHR of 60 to 69 bpm.

According to multivariate Cox regression analysis, an RHR of 70 to 79 bpm and 80 bpm or more were significantly associated with an increased risk for cardiovascular events (RHR 70-79 bpm: hazard ratio [HR], 1.50 [95% CI, 1.03-2.20; P =.037]; and RHR ≥80 bpm: HR, 1.62 [95% CI, 1.11-2.36; P =.012]) vs an RHR of 60 to 69 bpm in Model 4, which included data on use of calcium channel blockers, diuretics, angiotensin receptor blockers/angiotensin converting enzyme inhibitors, and β blockers.

Regarding nonrenal cardiovascular events, the event risk was significantly increased in patients who had an RHR of 70 to 79 bpm and those with an RHR 80 bpm or more vs those with an RHR of 60 to 69 bpm, with no significant association between RHR and renal events.

HRs for cardiovascular events according to baseline RHR suggested that the cardiovascular risk was not linearly increased with RHR but was similarly high in the range of 70 bpm or more.

The heart rates for cardiovascular events were 1.40 (95% CI, 0.93-2.10; P =.11) in patients with an RHR of 70 to 79 bpm and 1.51 (95% CI, 1.02-2.25; P =.041) in patients with an RHR of 80 bpm or more in the multivariate analysis in Model 4 without β blocker use.

The results of this study may not be applicable to other diabetic populations, such as those with earlier stages of diabetes without microvascular complication or with microvascular complications other than retinopathy. Also, detailed information was not available regarding methods of heart rate measurement except that it was measured in a seated position at a clinic or hospital. Furthermore, the association with daily exercise could not be analyzed and some confounders are possible.

“Evaluation of RHR may be useful in stratifying high-risk patients among T2DM patients with microvascular complications but without prior cardiovascular disease,” the investigators wrote.

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.