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

Type 1 diabetes, its complications, and non-ischemic cardiomyopathy: a mendelian randomization study of European ancestry

BACKGROUND

Type 1 diabetes (T1D) is a significant risk factor for a range of cardiovascular diseases. Nonetheless, the causal relationship between T1D and non-ischemic cardiomyopathy (NICM) remains to be elucidated. Furthermore, the mechanisms responsible for the progression from T1D to NICM have not been definitively characterized.

OBJECTIVE

The aim of this study was to conduct a Mendelian randomization (MR) study to investigate the causal effects of T1D and its complications on the development of NICM. Additionally, this study aimed to conduct a mediation analysis to identify potential mediators within this correlation.

METHODS

Genetic variants were used as instrumental variables for T1D. The summary data for T1D were obtained from two genome-wide association study datasets. The summary data for T1D with complications and NICM were obtained from the Finnish database. Two-sample MR, multivariable MR and mediation MR were conducted in this study.

RESULTS

The study revealed a causal association between T1D, T1D with complications, and NICM (with odds ratios of 1.02, 95% CI 1.01-1.04, p = 1.17e-04 and 1.03, 95% CI 1.01-1.05, p = 3.15e-3). Even after adjusting for confounding factors such as body mass index and hypertension, T1D remained statistically significant (with odds ratio of 1.02, 95% CI 1.01-1.04, p = 1.35e-4). Mediation analysis indicated that monokine induced by gamma interferon may play a mediating role in the pathogenesis of T1D-NICM (mediation effect indicated by odds ratio of 1.005, 95% CI 1.001-1.01, p = 4.9e-2).

CONCLUSION

The study demonstrates a causal relationship between T1D, its complications, and NICM. Additionally, monokine induced by gamma interferon may act as a potential mediator in the pathogenesis of T1D-NICM.

Relationship between active Helicobacter pylori infection and anemia, iron deficiency, iron deficiency anemia: A cross‐sectional study in a sub‐Saharan setting

Background and Aim

There have been contradictory reports about the association between Helicobacter pylori infection and iron deficiency anemia (IDA). Based on the high frequency of H. pylori infection in Cameroon, we have evaluated the frequency of H. pylori infection as the cause of anemia, and IDA among dyspeptic patients in Cameroon.

Methods

This cross‐sectional study enrolled 842 dyspeptic patients (472 women and 370 men) in two reference hospitals in Douala‐Cameroon. Each participant gave a written consent, and the study was approved by the National Ethical Committee. Erythroid‐related indices and markers of iron deficiency (ID) measurement were done for each participant as well as H. pylori detection. Data were analyzed using SSPS statistical package.

Results

The prevalence of anemia, ID, IDA, and H. pylori infection was 65.08%, 31.47%, 25.65%, and 80.88%, respectively. H. pylori infected individuals had a significantly lower mean value of hemoglobin (P = 0.01), hematocrit (P = 0.04), ferritin (P = 0.03) and coefficient of transferrin saturation (CTS) levels (P = 0.04) and a significantly higher mean value of mean corpuscular hemoglobin concentration (MCHC) (P = 0.02). Compared with H. pylori non‐infected participants, H. pylori infected patients were 1.2938 (95% confidence interval [CI]: 0.9087–1.8421), 1.1851 (95% CI: 0.8122–1.7292), and 1.5636 (95% CI: 1.0206–2.3953) times at higher risk to develop anemia, ID, and IDA, respectively. A significant relationship was found between H. pylori infection and IDA (P = 0.04 and 0.04 for crude and age/sex‐adjusted, respectively).

Conclusion

H. pylori infection seems to be associated with anemia, and IDA among dyspeptic patients in our milieu.

Management of iron deficiency in chronic heart failure

Iron deficiency is frequent in patients with chronic heart failure (CHF) with a prevalence of 50%, and its frequency varies depending on the study groups. The presence of iron deficiency limits erythropoiesis, leading to the development of anemia over time in patients with CHF, regardless of gender, race, and left ventricular ejection fraction (LVEF). Observational studies demonstrate a higher prevalence of iron deficiency in women and in patients with higher NYHA (New York Heart Association) functional class, decreased LVEF, increased brain natriuretic peptide (NT-proBNP), or increased high-sensitivity C-reactive protein. Iron deficiency and anemia in patients with CHF are independently associated with a decreased exercise capacity, hospitalizations for CHF, an increase in overall mortality and mortality from cardiovascular diseases. The clinical significance of iron deficiency requires the need to diagnose iron metabolism in all patients with CHF. Current guidelines for the diagnosis and treatment of CHF indicate the need to determine the level of ferritin and saturation of transferrin in all patients with a suspected diagnosis of heart failure. The use of oral iron therapy in patients with CHF demonstrates its low efficacy in correcting this condition according to the clinical trials. At the same time the use of intravenous iron therapy is safe and improves symptoms, exercise capacity and quality of life in patients with heart failure with reduced ejection fraction and iron deficiency, which has been shown both in international placebo-controlled trials and meta-analyses. The use of iron carboxymaltose should improve CHF symptoms, exercise capacity and quality of life in patients with CHF and LVEF45%. Intravenous iron therapy has also been shown to reduce readmissions for CHF in patients with an LVEF50% who have recently been hospitalized for worsening CHF.

Impact of change in iron status over time on clinical outcomes in heart failure according to ejection fraction phenotype

Aims

The importance of iron deficiency (ID) in heart failure with preserved ejection fraction (HFpEF) is unknown. In HF with reduced ejection fraction (HFrEF), ID is reported as an independent predictor of mortality in HF although not all published studies agree. Different definitions of ID have been assessed, and the natural history of untreated ID not established, which may explain the conflicting results. This study aimed to assess the relationship between ID and mortality in HFpEF, clarify which definition of ID correlates best with outcomes in HFrEF, and determine the prognostic importance of change in ID status over time.

Methods and results

Analyses were conducted on data from 1563 patients participating in a prospective international cohort study comparing HFpEF with HFrEF. Plasma samples from baseline and 6 month visits were analysed for the presence of ID. Two ID definitions were evaluated: ID_Ferritin = ‘ferritin < 100 mcg/L or ferritin 100–300 mcg/L + transferrin saturation < 20%’ and ID_Tsat = ‘transferrin saturation < 20%’. The risk of all‐cause mortality and death/HF hospitalization associated with baseline ID (ID_Ferritin or ID_Tsat) and change in ID status at 6 months (persistent, resolving, developing, or never present) was estimated in multivariable Cox proportional hazards models. Of 1563 patients, 1115 (71%) had HFrEF and 448 (29%) HFpEF. Prevalence of ID was similar in HFpEF and HFrEF (58%). Patients with ID were more likely to be female, diabetic, and have a higher co‐morbid burden than patients without ID. ID by either definition did not confer independent risk for either all‐cause mortality or death/HF hospitalization for patients with HFpEF [ID_Ferritin hazard ratio (HR) 0.65 (95% confidence interval 0.40–1.05), P = 0.08; ID_Tsat HR 1.16 (0.72–1.87), P = 0.55]. In the overall study cohort (HFrEF + HFpEF) and HFrEF subgroup, ID_Ferritin was inferior to ID_Tsat in prediction of all‐cause mortality [overall cohort: HR 1.21 (0.95–1.53), P = 0.12 vs. HR 1.95 (1.52–2.51), P < 0.01; HFrEF: HR 1.12 (0.85–1.48), P = 0.43 vs. HR 1.57 (1.15–2.14), P < 0.01]. Persistence of ID_Tsat at 6 months was strongly associated with poor outcomes compared with never having ID_Tsat [HR 2.22 (1.42–3.46), P < 0.01] or having ID_Tsat at baseline self‐resolve by 6 months [HR 1.40 (1.06–1.86), P = 0.02].

Conclusions

Iron deficiency is equally prevalent in HFpEF and HFrEF but is negatively prognostic only in HFrEF. The natural history of ID is important; persistent ID is strongly associated with mortality whereas resolution is not. ID_Tsat is the superior definition of ID and should inform future trials investigating the efficacy of intravenous iron replacement in patients with HFrEF.

PATTERN OF ANAEMIA AND ITS CORRELATES IN NIGERIANS WITH HEART FAILURE

BACKGROUND

Heart failure often coexists with many comorbidities, including anaemia. However, the pattern of anaemia in heart failure and its clinical and echocardiographic associations have not been adequately studied among Nigerians.

OBJECTIVE

To describe the pattern of anaemia, its clinical characteristics, and its echocardiographic associations among heart failure subjects in Nigeria.

METHODOS

One hundred and forty subjects with heart failure were recruited from the cardiology clinics of two teaching hospitals in southwest Nigeria: Ladoke Akintola University of Technology and Bowen University Teaching Hospitals, Ogbomoso. Complete blood analyses, among other tests, were done. Statistical analysis was done with Statistical Package for the Social Sciences (SPSS) 20.0. P <0.05 was taken as statistically significant.

RESULTS

Anaemia, as defined by the World Health Organisation, occurred in 106 (75.7%) of the heart failure patients. The patterns of anaemia among participants include combined anaemia of chronic diseases (ACD) with iron deficiency in 64 (45.7%) patients, and ACD alone in 40 (28.6%). Anaemia was more significantly associated with previous diagnosis of diabetes mellitus, presence of pulmonary hypertension, and heart failure with reduced ejection fraction. Mean systolic and diastolic blood pressures, ejection fraction, and fractional shortening were significantly lower among heart failure subjects with anaemia, while serum creatinine, left atrial dimension, left ventricular end diastolic dimension, and left ventricular mass index were significantly higher among heart failure subjects with anaemia compared to those without anaemia.

CONCLUSION

Anaemia occurs very frequently among heart failure patients in southwest Nigeria. It is associated with many poor prognostic factors, including diabetes mellitus, pulmonary hypertension, and kidney failure.

Anaemia and iron deficiency in heart failure: epidemiological gaps, diagnostic challenges and therapeutic barriers in sub-Saharan Africa

Anaemia and iron deficiency (ID) are common and of prognostic importance in heart failure (HF). In both conditions the epidemiology, diagnosis and therapies have been extensively studied in high-income countries but are still largely unexplored in sub-Saharan Africa (SSA). The lack of adequate and robust epidemiological data in SSA makes it difficult to recognise the significance of anaemia and ID in HF. From a clinical perspective, less attention is paid by clinicians to screening for anaemia in HF, and as far as interventions are concerned, there are no clinical trials in SSA that provide guidance on the appropriate interventional approach. Therefore studies are needed to provide more insight into the burden and peculiarities of and intervention for anaemia and ID in HF in SSA, where the pathophysiology might be different from that in high-income countries. There is increasing appreciation that targeting ID may serve as a useful additional treatment strategy for patients with chronic HF in high-income countries. However, there is limited information on the diagnosis of and therapy for ID in HF in SSA, where infections and malnutrition are more likely to influence the situation. This article reviews the present epidemiological gap in knowledge about anaemia and ID in HF, as well as the diagnostic and therapeutic challenges in SSA.

Impact of iron deficiency on exercise capacity and outcome in heart failure with reduced, mid-range and preserved ejection fraction

BACKGROUND

Little information is available about the prevalence and impact on exercise capacity and outcome of iron deficiency in heart failure with mid-range (HFmrEF) and preserved (HFpEF) ejection fraction in comparison to heart failure with reduced ejection-fraction (HFrEF). Furthermore, no data is available about the progression of ID in patients without baseline anaemia.

METHODS

We evaluated baseline iron and haemoglobin-status in a single-centre, prospective heart failure database. Baseline functional status, VO_2max, echocardiography and clinical-outcome (all-cause mortality and heart failure admissions) were evaluated. ID, anaemia, HFrEF, HFmrEF and HFpEF were defined according to established criteria.

RESULTS

A total of 1197 patients (71% male) were evaluated (HFrEF, n = 897; HFmrEF, n = 229; HFpEF, n = 72). The overall prevalence of ID was 53% (50% in HFrEF; 61% in HFmrEF; 64% in HFpEF) and 36% for anaemia. ID was associated with a lower VO_2max in patients with HFrEF, HFmrEF and HFpEF (p < .001 in all). Iron status more closely related to a poor VO_2max than anaemia status (p < .001). Furthermore, poor clinical-outcome was more strongly associated with iron status than anaemia status. Exposing eight patients without anaemia to iron deficiency for 39 months resulted in one patient developing new-onset anaemia (defined as progression of ID). Patients with progression of ID exhibited a significant higher risk of heart failure hospitalisation and all-cause mortality (HR = 1.4; CI = 1.01-1.94; p = .046) than patients without progression.

CONCLUSIONS

Iron deficiency is common in patients with HFrEF, HFmrEF and HFpEF, and negatively affects VO_2max and clinical-outcome. Progression of iron deficiency parallels an increased risk for worsening of heart failure.

Strengthening medical education in haematology and blood transfusion: postgraduate programmes in Tanzania

Haematology and blood transfusion, as a clinical and laboratory discipline, has a far-reaching impact on healthcare both through direct patient care as well as provision of laboratory and transfusion services. Improvement of haematology and blood transfusion may therefore be significant in achieving advances in health in Africa. In 2005, Tanzania had one of the lowest distributions of doctors in the world, estimated at 2·3 doctors per 100 000 of population, with only one haematologist, a medical doctor with postgraduate medical education in haematology and blood transfusion. Here, we describe the establishment and impact of a postgraduate programme centred on Master of Medicine and Master of Science programmes to build the capacity of postgraduate training in haematology and blood transfusion. The programme was delivered through Muhimbili University of Health and Allied Sciences (MUHAS) with partnership from visiting medical and laboratory staff from the UK and complemented by short-term visits of trainees from Tanzania to Haematology Departments in the UK. The programme had a significant impact on the development of human resources in haematology and blood transfusion, successfully training 17 specialists with a significant influence on delivery of health services and research. This experience shows how a self-sustaining, specialist medical education programme can be developed at low cost within Lower and Middle Income Countries (LMICs) to rapidly enhance delivery of capacity to provide specialist services.

Hematology in Africa

This review of hematology in Africa highlights areas of current practice and the immediate needs for development and clinical research. Acute hematological practice is dominated by anemia, sickle cell disease, and the need to provide a safe and rapidly available supply of blood. There is a growing need for specialist services for bleeding and coagulation, hematological malignancy, and palliative care. There are many areas of practice where straightforward measures could yield large gains in patient care. There is an urgent need for good clinical research to describe the epidemiology, natural history, and management of hematological diseases in Africa.

The heart of Africa: succeeding against the odds

South Africa and other areas of sub-Saharan Africa have in the past 20 years undergone rapid demographical changes, largely due to urbanisation and changes in lifestyle. This rapid change has led to a marked increase in specific cardiac conditions, such as hypertensive heart disease and coronary artery disease (with the highest prevalence in the middle-aged population), in conjunction with a range of other heart diseases, which are historically common in Africa-eg, rheumatic heart disease, cardiomyopathies, and unoperated congenital heart disease. The short supply of well-equipped screening facilities, late diagnosis, and inadequate care at primary, secondary, and tertiary levels have led to a large burden of patients with poorly treated heart failure. Excellent progress has been made in the understanding of the epidemiology, sociodemographical factors, effect of urbanisation, and pathophysiology of cardiac conditions, such as peripartum cardiomyopathy, rheumatic heart disease, and tuberculous pericarditis, which are common in sub-Saharan Africa. This progress has been achieved largely through several studies, such as the Heart of Soweto, THESUS, REMEDY, BA-HEF, Abeokuta-HF, and the PAPUCO studies. Studies on the suitable therapeutic management of several heart conditions have also been done or are underway. In this Lecture, I provide a personal perspective on the evolving burden of cardiac disease, as witnessed since my appointment at Chris Hani Baragwanath Hospital, in Soweto, South Africa, in 1992, which was also the year that the referendum to end apartheid in South Africa was held. Subsequently, a network of cardiologists was formed under the umbrella of the Heart of Africa Studies and the Pan African Cardiac Society. Furthermore, I summarise the major gaps in the health-care system dealing with the colliding epidemic of communicable and non-communicable heart diseases, including cardiac diseases common in peripartum women. I also touch on the fantastic opportunities available for doing meaningful research with enthusiastic colleagues and, thereby, having a large effect, despite the need to be highly innovative in finding much needed funding support.

Heart failure in Tanzania and Sweden: Comparative characterization and prognosis in the Tanzania Heart Failure (TaHeF) study and the Swedish Heart Failure Registry (SwedeHF)

BACKGROUND

Heart failure (HF) in developing countries is poorly described. We compare characteristics and prognosis of HF in Tanzania vs. Sweden.

METHODS

A prospective cohort study was conducted from the Tanzania HF study (TaHeF) and the Swedish HF Registry (SwedeHF). Patients were compared overall (n 427 vs. 51,060) and after matching 1:3 by gender and age±5years (n 411 vs. 1232). The association between cohort and all-cause mortality was assessed with multivariable Cox regression.

RESULTS

In the unmatched cohorts, TaHeF (as compared to SwedeHF) patients were younger (median age [interquartile range] 55 [40-68] vs. 77 [64-84] years, p<0.001) and more commonly women (51% vs. 40%, p<0.001). The three-year survival was 61% in both cohorts. In the matched cohorts, TaHeF patients had more hypertension (47% vs. 37%, p<0.001), more anemia (57% vs. 9%), more preserved EF, more advanced HF, longer duration of HF, and less use of beta-blockers. Crude mortality was worse in TaHeF (HR 2.25 [95% CI 1.78-2.85], p<0.001), with three-year survival 61% vs. 83%. However, covariate-adjusted risk was similar (HR 1.07, 95% CI 0.69-1.66; p=0.760). In both cohorts, preserved EF was associated with higher mortality in crude but not adjusted analysis.

CONCLUSIONS

Compared to in Sweden, HF patients in Tanzania were younger and more commonly female, and after age and gender matching, had more frequent hypertension and anemia, more severe HF despite higher EF, and worse crude but similar adjusted prognosis.