Effect of sodium-glucose cotransporter-2 inhibitors on haemoglobin and haematocrit levels in heart failure: a systematic review and meta-analysis

The aim of this study is to evaluate the effects of sodium-glucose cotransporter-2 (SGLT2) inhibitors on haemoglobin (Hb) and haematocrit (Hct) levels in patients with heart failure (HF). We systematically searched PubMed, Web of Science, Cochrane Library, and Embase for randomized controlled trials (RCTs) until April 2025. Changes in Hb and Hct were evaluated in HF patients treated with SGLT2 inhibitors compared to control subjects. A random-effects model was applied to calculate mean differences (MDs) with corresponding 95% confidence intervals (CIs). Subgroup analyses were performed across different SGLT2 inhibitors, follow-up durations, and types of control groups. Between-study heterogeneity was quantified using the I2 statistic, and meta-regression analyses were performed to explore the influence of baseline clinical characteristics on haematologic responses. Publication bias was evaluated using funnel plots and Egger's test. Seventeen randomized controlled trials (RCTs) with 16 784 participants (mean age 68.65 years, 65.56% male) were included. Sodium-glucose cotransporter-2 inhibitors significantly increased Hb (MD = 0.68 g/dl, 95% CI: 0.53; 0.83, I2 = 39.7%, P-value <.0001) and Hct (MD = 2.15%, 95% CI: 1.73; 2.57, I2 = 66.6%, P-value < .0001) compared with controls. Subgroup analyses showed consistent benefits across individual SGLT2 inhibitors, duration of follow-up (≥6 months vs <6 months), and comparator type (placebo vs active control). There was no evidence of publication bias. Sodium-glucose cotransporter-2 inhibitors significantly increase levels of Hb and Hct in patients with HF. Further research is warranted to assess clinical significance in relation to Hb and Hct changes in patients with pre-existing anaemia or renal dysfunction.