Prevalent Diabetes Mellitus: Mortality and Management in Norwegian Heart Failure Outpatients

Abstract

Objectives: Heart failure (HF) patients with diabetes mellitus experience poor prognosis. We assessed the independent predictive effect of prevalent diabetes mellitus on all-cause mortality in HF outpatients. Furthermore, we investigated if optimized HF medication differed in diabetic versus nondiabetic patients. Methods: From 6,289 patients included in the Norwegian HF registry during 2000-2012, 724 diabetic HF outpatients were propensity-score-matched with nondiabetic HF outpatients (1:1), based on 21 measured baseline variables. Baseline characteristics, measured comorbidities and medication were balanced in the matched sample. Results: Diabetes was not an independent predictor of all-cause mortality in the propensity-matched analyses (hazard ratio 1.041; 95% confidence interval 0.875-1.240). No interactions were found between the prognostic impact of diabetes and the strata renal function, systolic function or etiology of chronic HF. Diabetic HF outpatients were independently prescribed higher doses of β-blockers and loop diuretics (both p < 0.001) and were more prone to receive statins (p = 0.003) than nondiabetics. Conclusions: Prevalent diabetes mellitus was not an independent predictor of all-cause mortality in HF outpatients. Explanations other than tight glycemic control should be assessed to improve the prognosis of diabetic HF outpatients. The more intensive, optimized HF medication for diabetic HF outpatients may, to a certain degree, explain our results.

β-Blocker Doses and Heart Rate in Patients with Heart Failure: Results from the National Norwegian Heart Failure Registry

“…A meta-analysis has shown that a large majority (> 90%) of patients with diabetes mellitus and a reduced LVEF used a β-blocker [29]. That is the case in this study, where patients with diabetes mellitus used even higher doses than patients without diabetes mellitus, and it was also shown in a previous study from the older Norwegian HF registry [30]. It is therefore certain that the patients with obstructive pulmonary disease (COPD/asthma) and diabetes mellitus in our study contributed to a large extent to the high number of patients with a high HR and that these patients used on average a higher β-blocker dose than the patients with an HR < 70 bpm.…”

Problems, Pitfalls and Encouraging Information on Patients with Diabetes and Heart Failure

“…In conclusion, despite some unavoidable limitations, the results presented by Stubnova et al [7] are promising. A subgroup of patients with diabetes and heart failure and cared for in an outpatient setting did not, as would have been expected, have a compromised survival compared with their counterparts free from diabetes.…”

“…In this context, the report from the Norwegian Heart Failure Registry in this issue of Cardiolog y [7], indicating that, following adjustment for comorbidities, outpatients with diabetes and heart failure have a similar prognosis to those without diabetes, is encouraging although surprising. In a recent national report from another Scandinavian country, Sweden, diabetes was indeed an independent predictor of mortality with an adjusted odds ratio of 1.60 (95% confidence interval 1.50-1.71) [5].…”

“…Stubnova et al [7] suggest that a more extensive treatment with beta-blockers in the diabetes group may be an explanation for the lack of difference in mortality. This may indeed have contributed.…”

“…Moreover, the rate of subsequent events is considerably higher for insulin-treated patients (a proxy for diabetes duration) after a first percutaneous coronary intervention compared to patients treated with oral glucose-lowering agents [12]. The authors of the Norwegian report made great efforts to control for potential confounders by creating a propensity score [7]. Unfortunately, such a score cannot include nonreported variables, limiting the subsequent 1:1 propensity score matching to available information and, even if carefully prepared, it can never replace randomised trials.…”