Michael Boele van Hensbroek

Severe Anemia in Malawian Children

BACKGROUND Severe anemia is a major cause of sickness and death in African children, yet the causes of anemia in this population have been inadequately studied. METHODS We conducted a case-control study of 381 preschool children with severe anemia (hemoglobin concentration, <5.0 g per deciliter) and 757 preschool children without severe anemia in urban and rural settings in Malawi. Causal factors previously associated with severe anemia were studied. The data were examined by multivariate analysis and structural equation modeling. RESULTS Bacteremia (adjusted odds ratio, 5.3; 95% confidence interval [CI], 2.6 to 10.9), malaria (adjusted odds ratio, 2.3; 95% CI, 1.6 to 3.3), hookworm (adjusted odds ratio, 4.8; 95% CI, 2.0 to 11.8), human immunodeficiency virus infection (adjusted odds ratio, 2.0; 95% CI, 1.0 to 3.8), the G6PD(-202/-376) genetic disorder (adjusted odds ratio, 2.4; 95% CI, 1.3 to 4.4), vitamin A deficiency (adjusted odds ratio, 2.8; 95% CI, 1.3 to 5.8), and vitamin B12 deficiency (adjusted odds ratio, 2.2; 95% CI, 1.4 to 3.6) were associated with severe anemia. Folate deficiency, sickle cell disease, and laboratory signs of an abnormal inflammatory response were uncommon. Iron deficiency was not prevalent in case patients (adjusted odds ratio, 0.37; 95% CI, 0.22 to 0.60) and was negatively associated with bacteremia. Malaria was associated with severe anemia in the urban site (with seasonal transmission) but not in the rural site (where malaria was holoendemic). Seventy-six percent of hookworm infections were found in children under 2 years of age. CONCLUSIONS There are multiple causes of severe anemia in Malawian preschool children, but folate and iron deficiencies are not prominent among them. Even in the presence of malaria parasites, additional or alternative causes of severe anemia should be considered.

Residual neurologic sequelae after childhood cerebral malaria

BACKGROUND Cerebral malaria is an important cause of pediatric hospital admissions in the tropics. It commonly leads to neurologic sequelae, but the risk factors for this remain unclear and the long-term outcome unknown. OBJECTIVE The purpose of this study was to identify the common forms of neurologic sequelae that occur after cerebral malaria, their evolution over time, and the major clinical risk factors for residual disability. STUDY DESIGN Prospective study in 624 children admitted with cerebral malaria to two hospitals in The Gambia, West Africa. RESULTS We found that 23.3% of survivors had neurologic sequelae on discharge from the hospital. By 1 month the proportion had decreased to 8.6%, and at 6 months only 4.4% of survivors were found to have residual neurologic sequelae. The most common forms of neurologic sequelae were paresis and ataxia, often found in combination with other neurologic abnormalities. In a multiple logistic regression analysis, depth of coma on admission, multiple convulsions, and duration of unconsciousness were the only three independent risk factors. Hypoglycemia and lactate acidosis were not predictive of sequelae, although they are important risk factors for fatality. CONCLUSION This finding raises the possibility that fatal outcome and neurologic sequelae arise from separate pathologic processes.

HIV-associated anemia in children: a systematic review from a global perspective

Objectives:To assess the importance of anemia in HIV-infected children in western and tropical settings. Design:A systematic review with a descriptive component. Methods:Four databases were searched and reference lists of pertinent articles were checked. Studies that reported data on anemia or hemoglobin levels in HIV-infected children were selected and grouped according to the location and the definition of anemia. Results:Thirty-six studies met the inclusion criteria. Mild (hemoglobin <11 g/dl) and moderate (hemoglobin <9 g/dl) anemia were more prevalent with HIV infection (odds ratio 4.5; 95% confidence interval 2.5–8.3 and odds ratio 4.5; 95% confidence interval 2.0–10.3, respectively). Mean hemoglobin levels were lower (standardized mean difference; 0.79; 95% confidence interval 0.47–1.10). These differences were observed in both western and tropical settings. Anemia incidence ranged from 0.41 to 0.44 per person-year. There was limited data on more severe anemia (hemoglobin <7 or <5 g/dl). As anemia was frequently identified as an independent risk factor for disease progression and death, we next reviewed the limited data to formulate better strategies. Failure of erythropoiesis was the most important mechanism for anemia in HIV-infected children. Therapeutic options include highly active antiretroviral therapy and prevention or treatment of secondary infections. Erythropoietin can improve anemia in children, but it has not been evaluated in developing countries. Micronutrient supplementation may be helpful in individual children. The potential benefits or risks of iron supplementation in HIV-infected children require evaluation. Conclusion:Anemia is a very common complication of pediatric HIV infection, associated with a poor prognosis. With the increasing global availability of highly active antiretroviral therapy, more data on the safety and efficacy of possible interventions in children are urgently needed.

Iron Status Predicts Malaria Risk in Malawian Preschool Children

Introduction Iron deficiency is highly prevalent in pre-school children in developing countries and an important health problem in sub-Saharan Africa. A debate exists on the possible protective effect of iron deficiency against malaria and other infections; yet consensus is lacking due to limited data. Recent studies have focused on the risks of iron supplementation but the effect of an individuals iron status on malaria risk remains unclear. Studies of iron status in areas with a high burden of infections often are exposed to bias. The aim of this study was to assess the predictive value of baseline iron status for malaria risk explicitly taking potential biases into account. Methods and materials We prospectively assessed the relationship between baseline iron deficiency (serum ferritin <30 µg/L) and malaria risk in a cohort of 727 Malawian preschool children during a year of follow-up. Data were analyzed using marginal structural Cox regression models and confounders were selected using causal graph theory. Sensitivity of results to bias resulting from misclassification of iron status by concurrent inflammation and to bias from unmeasured confounding were assessed using modern causal inference methods. Results and Conclusions The overall incidence of malaria parasitemia and clinical malaria was 1.9 (95% CI 1.8–2.0) and 0.7 (95% CI 0.6–0.8) events per person-year, respectively. Children with iron deficiency at baseline had a lower incidence of malaria parasitemia and clinical malaria during a year of follow-up; adjusted hazard ratios 0.55 (95%-CI:0.41–0.74) and 0.49 (95%-CI:0.33–0.73), respectively. Our results suggest that iron deficiency protects against malaria parasitemia and clinical malaria in young children. Therefore the clinical importance of treating iron deficiency in a pre-school child should be weighed carefully against potential harms. In malaria endemic areas treatment of iron deficiency in children requires sustained prevention of malaria.

Long term outcome of severe anaemia in Malawian children.

Background Severe anaemia is a common, frequently fatal, condition in African children admitted to hospital, but its long term outcome is unknown. Early reports that survivors may be at risk of additional late morbidity and mortality may have significant implications for child survival in Africa. We assessed the short and long term outcome of severe anaemia in Malawian children and identified potential risk factors for death and further severe anaemia. Methodology and Findings For 18 months, we followed up children (6–60 months old) presenting to hospital with severe anaemia (haemoglobin ≤5g/dl) and their hospital and community controls with the aim to compare all cause mortality and severe anaemia recurrence rates between the groups, and to identify risk factors for these adverse outcomes. A total of 377 cases, 377 hospital controls and 380 community controls were recruited. Among cases, the in-hospital mortality was 6.4% and post-discharge all cause mortality was 12.6%, which was significantly greater than in hospital controls (2.9%) or community controls (1.4%) (Log rank test, p<0.001). The incidence of recurrence of severe anaemia among the cases was 0.102 per child-year (95% Confidence Interval 0.075–0.138), and was significantly higher than the 0.007 per child-year (95% CI 0.003–0.015) in the combined controls (p<0.0001). HIV was the most important risk factor both for post-discharge mortality (Hazard Ratio 10.5, 95% CI 4.0–27.2) and for recurrence of severe anaemia (HR 5.6, 95% CI 1.6–20.1). Conclusions Severe anaemia carries a high ‘hidden’ morbidity and mortality occurring in the months after initial diagnosis and treatment. Because severe anaemia is very common, this is likely to contribute importantly to overall under-five mortality. If not adequately addressed, severe anaemia may be an obstacle to achievement of the Millennium development goal No.4 on child survival. Strategies to diagnose and properly treat HIV infected children early most likely will reduce the high post-discharge mortality in severe anaemia.

Marked Reduction in Prevalence of Malaria Parasitemia and Anemia in HIV-Infected Pregnant Women Taking Cotrimoxazole With Or Without Sulfadoxine-Pyrimethamine Intermittent Preventive Therapy during Pregnancy in Malawi

Background. Effectiveness of cotrimoxazole (CTX) compared with sulfadoxine-pyrimethamine (SP) intermittent-preventive-therapy (IPTp) for malaria in HIV-infected pregnant women is unknown. We examined effectiveness of CTX with or without SP-IPTp versus SP-IPTp at reducing malaria parasitemia and anemia. Methods. From 2005 to 2009, we conducted a cross-sectional study of HIV-infected pregnant women at Thyolo Hospital, Malawi. Blood was tested for malaria parasitemia and anemia (hemoglobin<11g/dl). Data were collected on use of anti-malaria interventions and other risk factors. CTX prophylaxis policy for HIV-infected pregnant women was introduced in 2007, but implementation problems resulted in some women receiving both CTX and SP-IPTp. Findings. We enrolled 1,142 women, of whom 1,121 had data on CTX and/or SP-IPTp intake. Of these, 49.7%, 29.8%, and 15.4% reported taking SP-IPTp only, CTX only and SP-IPTp plus CTX, respectively. Compared with women taking SP-IPTp, those taking SP-IPTp plus CTX and CTX were less likely to have malaria parasitemia (OR, [95%CI]: 0.09, [0.01-0.66] and 0.43, [0.19-0.97], respectively) or anemia (PR, [95% CI]: 0.67, [0.54-0.83] and 0.72, [0.61-0.83], respectively). Conclusion. In HIV-infected pregnant women, daily CTX was associated with reduced malaria parasitemia and anemia compared with SP-IPTp. CTX plus SP-IPTp was associated with further reduction in malaria parasitemia but toxicity was not fully assessed.

Real-time PCR Demonstrates Ancylostoma duodenale Is a Key Factor in the Etiology of Severe Anemia and Iron Deficiency in Malawian Pre-school Children

Background Hookworm infections are an important cause of (severe) anemia and iron deficiency in children in the tropics. Type of hookworm species (Ancylostoma duodenale or Necator americanus) and infection load are considered associated with disease burden, although these parameters are rarely assessed due to limitations of currently used diagnostic methods. Using multiplex real-time PCR, we evaluated hookworm species-specific prevalence, infection load and their contribution towards severe anemia and iron deficiency in pre-school children in Malawi. Methodology and Findings A. duodenale and N. americanus DNA loads were determined in 830 fecal samples of pre-school children participating in a case control study investigating severe anemia. Using multiplex real-time PCR, hookworm infections were found in 34.1% of the severely anemic cases and in 27.0% of the non-severely anemic controls (p<0.05) whereas a 5.6% hookworm prevalence was detected by microscopy. Prevalence of A. duodenale and N. americanus was 26.1% and 4.9% respectively. Moderate and high load A. duodenale infections were positively associated with severe anemia (adjusted odds ratio: 2.49 (95%CI 1.16–5.33) and 9.04 (95%CI 2.52–32.47) respectively). Iron deficiency (assessed through bone marrow examination) was positively associated with intensity of A. duodenale infection (adjusted odds ratio: 3.63 (95%CI 1.18–11.20); 16.98 (95%CI 3.88–74.35) and 44.91 (95%CI 5.23–385.77) for low, moderate and high load respectively). Conclusions/Significance This is the first report assessing the association of hookworm load and species differentiation with severe anemia and bone marrow iron deficiency. By revealing a much higher than expected prevalence of A. duodenale and its significant and load-dependent association with severe anemia and iron deficiency in pre-school children in Malawi, we demonstrated the need for quantitative and species-specific screening of hookworm infections. Multiplex real-time PCR is a powerful diagnostic tool for public health research to combat (severe) anemia and iron deficiency in children living in resource poor settings.

Iron supplementation in HIV-infected Malawian children with anemia: a double-blind, randomized controlled trial

BACKGROUND It is unknown whether iron supplementation in human immunodeficiency virus (HIV)-infected children living in regions with high infection pressure is safe or beneficial. A 2-arm, double-blind, randomized, controlled trial was conducted to examine the effects of iron supplementation on hemoglobin, HIV disease progression, and morbidity. METHODS HIV-infected Malawian children aged 6-59 months with moderate anemia (hemoglobin level, 7.0-9.9 g/dL) were randomly assigned to receive 3 mg/kg/day of elemental iron and multivitamins (vitamins A, C, and D) or multivitamins alone for 3 months. Participants were followed for 6 months. RESULTS A total of 209 children were randomly assigned to treatment, and 196 (93.8%) completed 6 months of follow-up. Iron supplementation was associated with greater increases in hemoglobin concentrations (adjusted mean difference [aMD], 0.60; 95% confidence interval [CI], .06-1.13; P = .03) and reduced the risk of anemia persisting for up to 6 months follow-up (adjusted prevalence ratio, 0.59; 95% CI, .38-.92; P = .02). Children who received iron had a better CD4 percentage response at 3 months (aMD, 6.00; 95% CI, 1.84-10.16; P = .005) but an increased incidence of malaria at 6 months (incidence rate, 120.2 vs 71.7; adjusted incidence rate ratio [aIRR], 1.81 [95% CI, 1.04-3.16]; P = .04), especially during the first 3 months (incidence rate, 78.1 vs 36.0; aIRR, 2.68 [95% CI, 1.08-6.63]; P = .03). CONCLUSIONS Iron supplementation in anemic HIV-infected children has beneficial effects on hemoglobin, anemia, and immunity but increases the risk of malaria. Thus, iron supplementation in HIV-infected children living in malaria-endemic areas should only be provided in combination with adequate protection from malaria. CLINICAL TRIALS REGISTRATION ISRCTN-62947977.

Pathophysiological Mechanisms of Severe Anaemia in Malawian Children

Background Severe anaemia is a major cause of morbidity and mortality in African children. The aetiology is multi-factorial, but interventions have often targeted only one or a few causal factors, with limited success. Methods and Findings We assessed the contribution of different pathophysiological mechanisms (red cell production failure [RCPF], haemolysis and blood loss) to severe anaemia in Malawian children in whom etiological factors have been described previously. More complex associations between etiological factors and the mechanisms were explored using structural equation modelling. In 235 children with severe anaemia (haemoglobin<3.2 mMol/L [5.0 g/dl]) studied, RCPF, haemolysis and blood loss were found in 48.1%, 21.7% and 6.9%, respectively. The RCPF figure increased to 86% when a less stringent definition of RCPF was applied. RCPF was the most common mechanism in each of the major etiological subgroups (39.7–59.7%). Multiple aetiologies were common in children with severe anaemia. In the final model, nutritional and infectious factors, including malaria, were directly or indirectly associated with RCPF, but not with haemolysis. Conclusion RCPF was the most common pathway leading to severe anaemia, from a variety of etiological factors, often found in combination. Unlike haemolysis or blood loss, RCPF is a defect that is likely to persist to a significant degree unless all of its contributing aetiologies are corrected. This provides a further explanation for the limited success of the single factor interventions that have commonly been applied to the prevention or treatment of severe anaemia. Our findings underline the need for a package of measures directed against all of the local aetiologies of this often fatal paediatric syndrome.

Intermittent preventive therapy for malaria with monthly artemether–lumefantrine for the post-discharge management of severe anaemia in children aged 4–59 months in southern Malawi: a multicentre, randomised, placebo-controlled trial

BACKGROUND Young children with severe malarial anaemia in Africa are at high risk of readmittance to hospital or death within 6 months of discharge. We aimed to assess whether 3 months of chemoprevention with artemether-lumefantrine reduced this risk. METHODS We did a randomised, placebo-controlled, multicentre trial in four hospitals in Malawi testing the efficacy and safety of intermittent preventive therapy post-discharge (IPTpd) in children aged 4-59 months admitted for severe malarial anaemia. All convalescent children who had completed a blood transfusion received artemether-lumefantrine at discharge and were randomly assigned by a computer-generated sequence to receive placebo or artemether-lumefantrine at 1 month and 2 months after discharge, providing about 1 month and 3 months of protection, respectively. Patients and study staff were masked throughout the study. The primary endpoint was a composite of all-cause mortality or hospital readmittance because of all-cause severe anaemia or severe malaria between 1 and 6 months after enrolment. This trial is registered, number ISRCTN89727873. RESULTS Of 1414 children enrolled, 708 were assigned to receive placebo and 706 the intervention. By 6 months, 192 children (14%) had died or were readmitted with severe malaria or severe anaemia. 1-6 months after randomisation, 109 primary events occurred in 85 children in the placebo group and 86 in 74 children in the intervention group (adjusted protective efficacy [PE] 31%, 95% CI 5-50; absolute rate reduction 11·7 per 100 children years, 95% CI 1·8-18·9; p=0·024). The protective effect was greatest during the IPTpd period (1-3 months), when 58 primary events occurred in 49 children in the placebo group and 37 in 34 children in the intervention group (PE 41%, 10-62; p=0·01), but was not sustained after the third month (4-6 months, PE 17%, -27 to 45; p=0·395). When episodes in the first month were included--ie, before the first dose of IPTpd, when both groups benefited from the post-treatment prophylactic effect of artemether-lumefantrine provided at discharge--the overall cumulative PE by 6 months was 26% (-2 to 46; p=0·06). INTERPRETATION In areas with intense malaria transmission, chemoprevention with IPTpd given to children with severe malarial anaemia might reduce rates of readmittance to hospital for severe anaemia or malaria. Studies to confirm these findings and to investigate different delivery mechanisms and cost-effectiveness are needed. FUNDING The Netherlands African Partnership for Capacity Development and Clinical Interventions Against Poverty Related Diseases, the UBS-Optimus Foundation, and the Gates Malaria Partnership.