Type 2 diabetes and heart failure: insights from the global DISCOVER study

Heart failure (HF) is increasingly recognized as a major cause of morbidity and mortality in patients with type 2 diabetes (T2D), but the global epidemiology and treatment of HF in T2D are not well defined. This study aimed to examine the global prevalence of HF and the incidence of HF over 3 years of follow-up in patients with T2D [by presence and absence of co-existing coronary artery disease (CAD)].

DISCOVER was a 3 year, prospective, observational study of T2D patients enrolled at initiation of second-line glucose-lowering therapy. Among 14 057 patients with T2D from 36 countries, 289 (2.1%) had a diagnosis of HF at enrolment; median prevalence across countries was 2.0% (inter-quartile range 1.0-3.1%). Patients with HF at baseline were more likely to be older [HF vs. no HF: 67 ± 12 vs. 57 ± 12 years, standardized difference (StDiff) = 84%] and have longer duration of T2D (8.1 ± 7.2 vs. 5.6 ± 5.2 years, StDiff = 40%), CAD (44% vs. 6%, StDiff = 97%), atrial fibrillation (21% vs. 1%, StDiff = 66%), and kidney disease (23% vs. 4%, StDiff = 55%). Patients with HF were less likely to be on metformin (66% vs. 79%, StDiff = 28%) and thiazolidinediones (5.5% vs. 10.6%, StDiff = 19%) but had similar use of other glucose-lowering medications. Among 9313 patients with follow-up data, there were 70 incident cases of HF, which translates to an incidence of 2.6 cases per 1000 person years. Of these incident HF cases, 60% occurred in the absence of pre-existing or concomitant CAD, and 73% were diagnosed in the outpatient setting.

In a large, global cohort of patients with T2D, the majority of incident cases of HF occurred in outpatients and in the absence of known CAD. These findings highlight the need for greater awareness of HF risk in patients with T2D.