Abstract

Introduction
Heart failure (HF) is a leading cause of hospitalisations worldwide. HF can lead to pulmonary hypertension (PH) due to backing up of blood into the pulmonary vasculature. Co-incidence of HF and PH is associated with a poor clinical prognosis. This systematic review and meta-analysis aims to analyse the prevalence of PH amongst individuals with HF.

Methods
Following a systematic search of MEDLINE and EMBASE, studies reporting the prevalence of PH amongst HF patients were included. An inverse-variance weighted meta-analysis of HF-PH prevalence, including subgroup analysis, was conducted. Prevalence is expressed according to the common and random effects models, respectively, with 95% confidence intervals (CI). The relationship between HF-PH prevalence and other comorbidities and characteristics were analysed using a meta-regression and Pearson’s R correlation coefficient (r).

Results
54 papers were identified for inclusion, with 269,187 HF patients. Of these, 50,828 patients had PH. HF-PH prevalence reported by different papers ranged from 13-94%. The overall prevalence estimates were 19% (CI:19-19%) and 49% (CI:42-56%). HF-PH prevalence was higher in those with reduced ejection fractions (15%, CI:14-16%; 36%, CI:23-51%) than those with preserved (27%, CI:26-27%; 60%, CI:45-73%). Meta-regression revealed that diabetes showed the strongest correlation with HF-PH prevalence (r= -0.429), whilst age and smoking showed almost no correlation. BMI and female gender displayed weakly positive correlations (r= 0.143 and 0.137, respectively).

Conclusions
There is notable variability in prevalence estimates reported by different papers, across different continents. Increased HF-PH prevalence in HF with reduced ejection fraction is consistent with the mechanism of pathology co-incidence. Diabetes could shorten HF patient life expectancy, minimising the chances of developing long-term complications like PH and explaining the negative correlation identified. To our knowledge, this is the first meta-analysis investigating the co-prevalence of HF and PH. Given its poor prognosis, understanding the underlying factors could contribute valuable clinical insight.