Preheart failure comorbidities and impact on prognosis in heart failure patients : a nationwide study

Background: Data regarding the impact of preheart failure (HF) comorbidities on the prognosis of HF are scarce, especially in the younger HF patients. Objectives: To investigate pre-existing comorbidities in HF patients versus matched controls and to assess their impact on mortality. Methods: We included all first-time in-hospital and outpatient diagnoses of HF from 1995 to 2017, and comorbidities antedating the HF-diagnosis in the Danish nationwide registries. HF patients were matched with up to five controls. One-year all-cause mortality rates and population attributable risk (PAR) were estimated for three separate age groups (≤50, 51–74 and >74 years). Results: Totally 280 002 patients with HF and 1 166 773 controls were included. Cardiovascular comorbidities, for example, cerebrovascular disease and ischaemic heart disease were more frequent in the oldest (17.9% and 29.7% in HF vs. 9.8% and 10.7% in controls) compared to the youngest age group (3.9% and 15.2% in HF vs. 0.7% and 0.9% in controls). Amongst patients with HF, 1-year mortality rates (per 100 person-years) were highest amongst those with >1 noncardiovascular comorbidity: ≤50 years (10.4; 9.64–11.3), 51–74 years (23.3; 22.9–23.7), >74 years (58.5; 57.9–59.0); hazard ratios 245.18 (141.45–424.76), 45.85 (42.77–49.15) and 24.5 (23.64–25.68) for those ≤50, 51–74 and >74 years, respectively. For HF patients ≤50 years, PAR was greatest for hypertension (17.8%), cancer (14.1%) and alcohol abuse (8.5%). For those aged >74 years, PAR was greatest for hypertension (23.6%), cerebrovascular disease (6.2%) and cancer (7.2%). Conclusions: Heart failure patients had a higher burden of pre-existing comorbidities, compared to controls, which adversely impacted prognosis, especially in the young