Prediabetes and incident heart failure in hypertensive patients: Results from the Swedish Primary Care Cardiovascular Database

BACKGROUNDS AND AIMS: The cardiovascular risk conferred by concomitant prediabetes in hypertension is unclear. We aimed to examine the impact of prediabetes on incident heart failure (HF) and all-cause mortality, and to describe time in therapeutic blood pressure range (TTR) in a hypertensive real-world primary care population. METHODS AND RESULTS: In this retrospective cohort study, 9628 hypertensive individuals with a fasting plasma glucose (FPG) in 2006-2010 but no diabetes, cardiovascular or renal disease were followed to 2016; median follow-up was 9 years. Prediabetes was defined as FPG 5.6-6.9 mmol/L, and in a secondary analysis as 6.1-6.9 mmol/L. Study outcomes were HF and all-cause mortality. Hazard ratios (HR) were compared for prediabetes with normoglycemia using Cox regression. All blood pressure values from 2001 to the index date (first FPG in 2006-2010) were used to calculate TTR. At baseline, 51.4% had prediabetes. The multivariable-adjusted HR (95% confidence intervals) was 0.86 (0.67-1.09) for HF and 1.06 (0.90-1.26) for all-cause mortality. For FPG defined as 6.1-6.9 mmol/L, the multivariable-adjusted HR were 1.05 (0.80-1.39) and 1.42 (1.19-1.70), respectively. The prediabetic group had a lower TTR (p < 0.05). CONCLUSIONS: Prediabetes was not independently associated with incident HF in hypertensive patients without diabetes, cardiovascular or renal disease. However, prediabetes was associated with all-cause mortality when defined as FPG 6.1-6.9 mmol/L (but not as 5.6-6.9 mmol/L). TTR was lower in the prediabetic group, suggesting room for improved blood pressure to reduce incident heart failure in prediabetes.