Iron deficiency in heart failure with preserved ejection fraction: a systematic review and meta-analysis

Objective Iron deficiency (ID) has an established impact on outcomes in patients with heart failure with reduced ejection fraction; however, there is a lack of conclusive evidence in patients with heart failure with preserved ejection fraction (HFpEF). We sought to clarify the prevalence and impact of ID in patients with HFpEF. Methods A systematic search of Cohcrane, MEDLINE, EMBASE, Web of Science and CINAHL electronic databases was performed to identify relevant studies. Included studies defined HFpEF as heart failure with an ejection fraction >= 50%. We used a random-effects meta-analysis to determine the composite prevalence of ID in patients with HFpEF across the included studies. Other outcomes were assessed with qualitative analysis due to a paucity of studies with comparable outcome measures. Results The prevalence of ID in the included studies was 59% (95% CI 52% to 65%). ID was associated with lower VO2 max in three of four studies reporting VO2 max as an outcome measure, lower functional status as determined by dyspnoea class or 6 min walk test in two of three studies, and worse health-related quality of life in both studies reporting on this outcome. Conversely, ID had no impact on death or hospitalisation in three of the four studies investigating this. Conclusions ID is highly prevalent in patients with HFpEF and is associated with worse exercise capacity and functional outcomes, but not hospitalisation or mortality. Our study establishes that ID may play an important a role in HFpEF.