HF prevalence in diabetes patients is underestimated in everyday clinical practice

SGLT2 inhibitors can significantly reduce the risk of hospitalization for heart failure (HF) and death from cardiovascular causes in patients with diabetes and HF. However, the diagnosis of HF is difficult. Scientists from St. Gallen therefore wanted to determine the prevalence of heart failure in patients with diabetes with and without SGLT2i in order to establish whether treatment guidelines need to be tightened and regular screening for HF introduced.

The guidelines of the European Society of Cardiology (ESC) recommend treating patients with heart failure first line with an SGLT2 inhibitor, regardless of whether they have type 2 diabetes or not. This applies primarily to patients with a reduced left ventricular ejection fraction (HFrEF), but recent clinical studies have also shown similar benefits for patients with a slightly reduced (HFmrEF) or preserved (HFpEF) ejection fraction, explained Dr. Frida Renström from the Department of Endocrinology, Diabetology, Osteology and Metabolic Diseases at the Cantonal Hospital of St. Gallen [1].

“The clinical guidelines are designed to be quite simple, but translating them into clinical practice is complicated because the actual diagnosis of heart failure is challenging.” It is a condition without specific signs and symptoms that can often be attributed to other pre-existing complications in patients with type 2 diabetes. Heart failure therefore often remains unrecognized and the prevalence in this patient population is therefore not really clear, the expert explained.

The aim of her study was therefore to find out whether regular screening for heart failure in patients with diabetes is necessary in tertiary diabetes care and whether the treatment guidelines need to be supplemented accordingly.

SwissDiab participants were screened for HF

Their study was embedded in the Swiss Diabetes Registry (SwissDiab), a multicenter, longitudinal observational study of outpatients with diabetes treated in tertiary care centers. Over an 18-month period, all patients attending an annual SwissDiab visit were evaluated for heart failure based on the diagnostic algorithm recommended by the ESC. Accordingly, patients with at least one of the symptoms

arterial hypertension,
Orthopnea,
nocturnal dyspnea,
Treatment with diuretics,
Rattling noises,
bilateral ankle edema,
Heart murmur or
Jugular vein dilation

plus an NT-proBNP ≥125 ng/l were referred to the Department of Cardiology for echocardiography and clinical evaluation of HF, with further stratification according to HFpEF, HFmrEF and HFrEF. LDL cholesterol was estimated on the basis of the Friedewald equation.

Patients who had already been diagnosed with heart failure or who had coronary heart disease and who had undergone an echocardiogram within the last 2 years were not re-examined. In these cases, the data was looked up in the medical records. Heart failure was diagnosed on the basis of the left ventricular ejection fraction (LVEF):

HFrEF = LVEF ≤40%
HFmrEF = LVEF 41-49%
HFpEF = LVEF ≥50% + structural and/or functional cardiac abnormalities

During the 18-month period, 555 SwissDiab patients were referred. 21 patients had to be excluded due to missing data. The mean age was 61 years, 30% were female, the majority of 60% had type 2 diabetes, and the time since diagnosis was 14 years. The average BMI was 28.4 ^kg/m2, the _HbA1c value was 7.1% and the LDL cholesterol was 2.1 mmol/l. 21.7% of the participants smoked.

“Of these patients, 11.2% (n=60) were diagnosed with heart failure, the majority – almost 57% (n=34) – had a preserved ejection fraction and 32% (n=19) had HFrEF,” explained Dr. Renström. The prevalence by diabetes type was 2.4% for type 1 diabetes (n=4), 16% for type 2 diabetes (n=51) and 10.6% (n=5) for other diabetes types. Of the HF cases identified, 60% (n=36) were newly diagnosed in this study, most of whom (83.3%) had type 2 diabetes. Looking at the prevalent cases, the majority had heart failure with reduced ejection fraction, while almost 78% of the newly diagnosed patients had heart failure with preserved ejection fraction (HFpEF: n=28; HFmrEF: n=4; HFrEF: n=4). Excluding patients with prevalent heart failure, this screening algorithm had a positive predictive value of almost 38%. Of the patients with prevalent heart failure, 50% were taking an SGLT2 inhibitor, two out of three patients had HFmrEF and 10 out of 15 had HFrEF. None of the group with a known diagnosis of HF had heart failure with preserved ejection fraction. All patients with HF who were treated with SGLT2i were type 2 diabetics.

One in six type 2 diabetics with HF

Approximately one in ten outpatients with diabetes in tertiary care who were included in SwissDiab had heart failure. In terms of type 2 diabetes only, it was one in six. Three out of five cases had not been previously diagnosed and had a preserved ejection fraction. Half of patients with previously diagnosed heart failure and two out of three patients with known HFrEF received an SGLT2 inhibitor, compared to less than one in three patients with HF overall.

Considering that the majority with HF were undiagnosed and half of patients with known HF were not receiving SGLT2i treatment, the results would indicate the need to raise awareness of HF and treatment in clinical practice.

Congress: EASD 2023

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