Association Between Type 2 Diabetes and All-Cause Hospitalization and Mortality in the UK General Heart Failure Population: Stratification by Diabetic Glycemic Control and Medication Intensification.

OBJECTIVES: This study sought to investigate in the general heart failure (HF) population, whether the associations between type 2 diabetes (T2D) and risk of hospitalization and death, are modified by changing glycemic or drug treatment intensity. BACKGROUND: In the general HF population, T2D confers a higher risk of poor outcomes, but whether this risk is modified by the diabetes status is unknown. METHODS: A nested case-control study in an incident HF database cohort (2002 to 2014) comparing patients with T2D with those without, for risk of all-cause first hospitalization and death. T2D was stratified by categories of glycosylated hemoglobin (HbA1c) or drug treatments measured 6 months before hospitalization and 1 year before death and compared with the HF group without T2D. RESULTS: In HF, T2D was associated with risk of first hospitalization (adjusted odds ratio [aOR]: 1.29; 95% confidence interval [CI]: 1.24 to 1.34) and mortality (aOR: 1.24; 95% CI: 1.29 to 1.40). Stratification of T2D by HbA1c levels, compared with the reference HF group without T2D, showed U-shaped associations with both outcomes. Highest risk categories were HbA1c >9.5% (hospitalization, aOR: 1.75; 95% CI: 1.52 to 2.02; mortality, aOR: 1.30; 95% CI: 1.24 to 1.47) and <5.5% (hospitalization, aOR: 1.42; 95% CI: 1.12 to 1.80; mortality, aOR: 1.29; 95% CI: 1.10 to 1.51, respectively). T2D group with change in HbA1c of >1% decrease was associated with hospitalization (aOR: 1.33; 95% CI: 1.18 to 1.49) and mortality (aOR: 1.36; 95% CI: 1.24 to 1.48). T2D drug group associations with hospitalization were no medication (aOR: 1.12; 95% CI: 1.04 to 1.19), oral antihyperglycemic only (aOR: 1.34; 95% CI: 1.27 to 1.41), oral antihyperglycemic+insulin (aOR: 1.36; 95% CI: 1.21 to 1.52), and insulin only (aOR: 1.61; 95% CI: 1.43 to 1.81); and with mortality the same were 1.31 (95% CI: 1.23 to 1.39), 1.16 (95% CI: 1.11 to 1.22), 1.19 (95% CI: 1.06 to 1.34), and 1.43 (95% CI: 1.31 to 1.57), respectively. The T2D group with reducing drug treatments were associated with hospitalization (aOR: 2.13; 95% CI: 1.68 to 2.69) and mortality (aOR: 2.09; 95% CI: 1.81 to 2.41). CONCLUSIONS: In the general HF population, T2D stratified by glycemic control and drug treatments showed differential risk associations. Routine measures of dynamic diabetes status provide important prognostic indication of poor outcomes in HF.