Prevalence and prognostic implications of anaemia and iron deficiency in Tanzanian patients with heart failure

Abstract

Objective: To determine the prevalence, correlates and prognostic implications of anaemia and iron deficiency (ID) in patients with heart failure (HF) in Tanzania.

Method: This was a cross-sectional and prospective observational study conducted at Muhimbili National Hospital in Dar es Salaam, Tanzania. Patients were ≥ 18 years of age, with HF defined according to the Framingham criteria. The primary outcome was anaemia and the secondary outcome was a composite of hospitalisation for HF or all-cause mortality.

Results: A total of 401 HF patients (median age 56 years, IQR 41-67 years; women 51%) were included. The prevalence of anaemia was 57%. The overall prevalence of ID was 49% distributed as 69% versus 21% in subjects with and without anaemia (p < 0.001). Normocytic anaemia was seen in 18% of the patients while none had macrocytic anaemia. The risk of having anaemia was positively associated with residency outside Dar es Salaam (OR 1.72 (95% CI 1.02 to 2.89); p = 0.038), atrial fibrillation (4.12 (1.60 to 10.61); p=0.003), LVEF < 45% (2.70 (1.57 to 4.67); p < 0.001) and negatively (ORs per unit decrease) with creatinine clearance (0.98 (0.97 to 0.99); p = 0.012) and total cholesterol (0.78 (0.63 to 0.98); p = 0.029). One-year survival free from a composite endpoint was 70%. The presence of ID anaemia increased the likelihood for an event (HR 2.67; 95% CI 1.39 to 5.07; p = 0.003), while anaemia without ID did not influence the risk.

Conclusions: ID anaemia was common in Tanzanian patients with HF and was independently associated with the risk for hospitalisation or death.

Figure 1

Flow chart of patients included in The Tanzania Heart Failure (TaHef) study for anaemia and iron deficiency analyses. MCV, mean corpuscular volume.

Figure 2

(A–D) Kaplan–Meier survival curves for composite endpoint by four different models of anaemia and iron deficiency.

Figure 3

Adjusted HRs for (A) haemoglobin (Hb) and (B) mean corpuscular volume (MCV) as independent predictors of composite endpoint among patients with heart failure. Results from Cox regression models showing the linear relationships of Hb and MCV with composite endpoint were overlaid on the plot of the spline model, demonstrating that the simpler parametric model adequately described the covariate effects. Dashed green lines represent the fit of the spline. Solid black lines represent the parametric Cox regression fit, while dotted lines represent pointwise 95% confidence limits for the parametric fits. All models were constrained to cross at a HR of unity. Distribution of patients across Hb and MCV are represented by underlaid histograms. Tick marks above the HR curve represent patients with composite endpoint, whereas tick marks below the curve represent patients without composite endpoint.