About one-third of patients with diabetes mellitus and heart failure (HF) are treated with insulin. However, since insulin causes sodium retention and hypoglycemia, its use might be associated with worse outcomes.

A new study published in the European Journal of Heart Failure proposed that other glucose-lowering treatments are probably safer than insulin therapy for patients with heart failure (HF) and type-2 diabetes mellitus.

The present study examined data from 24,012 patients with HF, from four large randomized trials, and an administrative database of 4 million individuals, 103,857 of whom had HF. The risk of hospitalization for HF was assessed in the former group. For the latter group, a case-control study within a population-based cohort study was conducted.

The results revealed that the prevalence of diabetes mellitus at baseline ranged from 25.5-29.5% across trials. Meanwhile, insulin alone or in combination with oral hypoglycemic drugs was prescribed at randomization to 24.4-34.5% of patients with diabetes. While, the rates of death from any cause and hospitalization for HF were higher in patients with diabetes than in those without; the highest rate being in patients who were prescribed insulin. Furthermore, insulin prescription was associated with a higher risk of all-cause death and re-hospitalization for HF.

In inference, it was stated that whether insulin use is associated with poor outcomes in HF should be investigated further with controlled trials.