Sickle Cell Disease: New Opportunities and Challenges in Africa.

Sickle cell disease (SCD) is one of the most common genetic causes of illness and death in the world. This is a review of SCD in Africa, which bears the highest burden of disease. The first section provides an introduction to the molecular basis of SCD and the pathophysiological mechanism of selected clinical events. The second section discusses the epidemiology of the disease (prevalence, morbidity, and mortality), at global level and within Africa. The third section discusses the laboratory diagnosis and management of SCD, emphasizing strategies that been have proven to be effective in areas with limited resources. Throughout the review, specific activities that require evidence to guide healthcare in Africa, as well as strategic areas for further research, will be highlighted

Statin utilization and cardiovascular outcomes in a real-world primary prevention cohort of older adults

Background: Statins are a cost-effective therapy for prevention of atherosclerotic cardiovascular disease (ASCVD). Guidelines on statins for primary prevention are unclear for older adults (\u3e75 years).Objective: Investigate statin utility in older adults without ASCVD events, by risk stratifying in a large healthcare network.Methods: We included 8,114 older adults, without CAD, PVD or ischemic stroke. Statin utilization based on ACC/AHA 10-year ASCVD risk calculation, was evaluated in intermediate (7.5%-19.9%) and high-risk patients (≥ 20%); and categorized using low and \u27moderate or high\u27 intensity statins with a follow up period of ∼7 years. Cox regression models were used to calculate hazard ratios for incident ASCVD and mortality across risk categories stratified by statin utilization. Data was adjusted for competing risk using Elixhauser Comorbidity Index.Results: Compared with those on moderate or high intensity statins, high-risk older patients not on any statin had a significantly increased risk of MI [HR 1.51 (1.17-1.95); p\u3c0.01], stroke [HR 1.47 (1.14-1.90); p\u3c0.01] and all-cause mortality [HR 1.37 (1.19-1.58); p\u3c0.001] in models adjusted for Elixhauser Comorbidity Index. When comparing the no statin group versus the moderate or high intensity statin group in the intermediate risk cohort, although a trend for increased risk was seen, it did not meet statistical significance thresholds for MI, stroke or all-cause mortality.Conclusion: Lack of statin use was associated with increased cardiovascular events and mortality in high-risk older adults. Given the benefits appreciated, statin use may need to be strongly considered for primary ASCVD prevention among high-risk older adults. Future studies will assess the risk-benefit ratio of statin intervention in older adults

Haptoglobin, alpha-thalassaemia and glucose-6-phosphate dehydrogenase polymorphisms and risk of abnormal transcranial Doppler among patients with sickle cell anaemia in Tanzania.

Transcranial Doppler ultrasonography measures cerebral blood flow velocity (CBFv) of basal intracranial vessels and is used clinically to detect stroke risk in children with sickle cell anaemia (SCA). Co-inheritance in SCA of alpha-thalassaemia and glucose-6-phosphate dehydrogenase (G6PD) polymorphisms is reported to associate with high CBFv and/or risk of stroke. The effect of a common functional polymorphism of haptoglobin (HP) is unknown. We investigated the effect of co-inheritance of these polymorphisms on CBFv in 601 stroke-free Tanzanian SCA patients aged <24 years. Homozygosity for alpha-thalassaemia 3·7 deletion was significantly associated with reduced mean CBFv compared to wild-type (β-coefficient -16·1 cm/s, P = 0·002) adjusted for age and survey year. Inheritance of 1 or 2 alpha-thalassaemia deletions was associated with decreased risk of abnormally high CBFv, compared to published data from Kenyan healthy control children (Relative risk ratio [RRR] = 0·53 [95% confidence interval (CI):0·35-0·8] & RRR = 0·43 [95% CI:0·23-0·78]), and reduced risk of abnormally low CBFv for 1 deletion only (RRR = 0·38 [95% CI:0·17-0·83]). No effects were observed for G6PD or HP polymorphisms. This is the first report of the effects of co-inheritance of common polymorphisms, including the HP polymorphism, on CBFv in SCA patients resident in Africa and confirms the importance of alpha-thalassaemia in reducing risk of abnormal CBFv

Transcranial Doppler and Magnetic Resonance in Tanzanian Children With Sickle Cell Disease

Background and Purpose: We determined prevalences of neurological complications, vascular abnormality, and infarction in Tanzanian children with sickle cell disease. // Methods: Children with sickle cell disease were consecutively enrolled for transcranial Doppler; those with slightly elevated (>150 cm/s), low (150 cm/s was associated with frequent painful crises and low hemoglobin level. Absent/low CBFv was associated with low hemoglobin level and history of unilateral weakness. In 49 out of 67 children with low/absent/elevated transcranial Doppler undergoing magnetic resonance imaging, 43% had infarction, whereas 24 out of 48 (50%) magnetic resonance angiographies were abnormal. One had hemorrhagic infarction; none had microbleeds. Posterior circulation infarcts occurred in 14%. Of 11 children with previous seizure undergoing magnetic resonance imaging, 10 (91%) had infarction (5 silent) compared with 11 out of 38 (29%) of the remainder ( P=0.003). Of 7 children with clinical stroke, 2 had recurrent stroke and 3 died; 4 out of 5 had absent CBFv. Of 193 without stroke, 1 died and 1 had a stroke; both had absent CBFv. // Conclusions: In one-third of Tanzanian children with sickle cell disease, CBFv is outside the normal range, associated with frequent painful crises and low hemoglobin level, but not hemolysis. Half have abnormal magnetic resonance angiography. African children with sickle cell disease should be evaluated with transcranial Doppler; those with low/absent/elevated CBFv should undergo magnetic resonance imaging/magnetic resonance angiography

The clinical presentation, utilization, and outcome of individuals with sickle cell anaemia presenting to urban emergency department of a tertiary hospital in Tanzania

Background Sickle cell anaemia (SCA) is prevalent in sub-Saharan Africa, with high risk of complications requiring emergency care. There is limited information about presentation of patients with SCA to hospitals for emergency care. We describe the clinical presentation, resource utilization, and outcomes of SCA patients presenting to the emergency department (ED) at Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania. Methods This was a prospective cohort study of consecutive patients with SCA presenting to ED between December 2014 and July 2015. Informed consent was obtained from all patients or patients’ proxies prior to being enrolled in the study. A standardized case report form was used to record study information, including demographics, relevant clinical characteristics and overall patients outcomes. Categorical variables were compared with chi-square test or Fisher’s exact test; continuous variables were compared with two-sample t-test or Mann-Whitney U-test. Results We enrolled 752 (2.7%) people with SCA from 28,322 patients who presented to the MNH-ED. The median age was 14 years (Interquartile range [IQR]: 6–23 years), and 395 (52.8%) were female. Pain 614 (81.6%), fever 289 (38.4%) were the most frequent presenting complaint. Patients with fever, hypoxia, altered mental status and bradycardia had statistically significant relative risk of mortality of 10.4, 153, 50 and 12.1 (p < 0.0001) respectively, compared to patients with normal vitals. Overall, 656 (87.2%) patients received Complete Blood Cell counts test, of these 342 (52.1%) had severe anaemia (haemoglobin < 7 g/dl), and a 30.3 (p = 0.02) relative risk of relative risk of mortality compare to patients with higher haemoglobin. Patients who had malaria, elevated renal function test and hypoglycemia, had relative risk of mortality of 22.9, 10.4 and 45.2 (p < 0.0001) respectively, compared to patient with normal values. Most 534 (71.0%) patients were hospitalized for in patients care, and the overall morality rate was 16 (2.1%). Conclusions We described the clinical presentation, management, and outcomes of patients with SCA presenting to the largest public ED in Tanzania, as well as information on resource utilization. This information can inform development of treatment guidelines, clinical staff education, and clinical research aimed at optimizing care for SCA patients

Relationships between sickle cell trait, malaria, and educational outcomes in Tanzania

Background: Sickle Cell Trait (SCT) has been shown to be protective against malaria. A growing literature suggests that malaria exposure can reduce educational attainment. This study assessed the relationship and interactions between malaria, SCT and educational attainment in north-eastern Tanzania. Methods: Seven hundred sixty seven children were selected from a list of individuals screened for SCT. Febrile illness and malaria incidence were monitored from January 2006 to December 2013 by community health workers. Education outcomes were extracted from the Korogwe Health and Demographic Surveillance system in 2015. The primary independent variables were malaria and SCT. The association between SCT and the number of fever and malaria episodes from 2006 to 2013 was analyzed. Main outcomes of interest were school enrolment and educational attainment in 2015. Results: SCT was not associated with school enrolment (adjusted OR 1.42, 95% CI [0.593,3.412]) or highest grade attained (adjusted grade difference 0.0597, 95% CI [−0.567, 0.686]). SCT was associated with a 29% reduction in malaria incidence (adjusted IRR 0.71, 95% CI [0.526, 0.959]) but not with fever incidence (adjusted IRR 0.905, 95% CI [0.709-1.154]). In subgroup analysis of individuals with SCT, malaria exposure was associated with reduced school enrollment (adjusted OR 0.431, 95% CI [0.212, 0.877]). Conclusions: SCT appears to reduce incidence of malaria. Overall, children with SCT do not appear to attend more years of school; however children who get malaria despite SCT appear to have lower levels of enrolment in education than their peers

A ten year review of the sickle cell program in Muhimbili National Hospital, Tanzania

Background: Africa has the highest burden of Sickle cell disease (SCD) but there are few large, systematic studies providing reliable descriptions of the disease spectrum. Tanzania, with 11,000 SCD births annually, established the Muhimbili Sickle Cell program aiming to improve understanding of SCD in Africa. We report the profile of SCD seen in the first 10 years at Muhimbili National Hospital (MNH). Methods: Individuals seen at MNH known or suspected to have SCD were enrolled at clinic and laboratory testing for SCD, haematological and biochemical analyses done. Ethnicity was self-reported. Clinical and laboratory features of SCD were documented. Comparison was made with non-SCD population as well as within 3 different age groups (< 5, 5-17 and ≥ 18 years) within the SCD population. Results: From 2004 to 2013, 6397 individuals, 3751 (58.6%) SCD patients, were enrolled, the majority (47.4%) in age group 5-17 years. There was variation in the geographical distribution of SCD. Individuals with SCD compared to non-SCD, had significantly lower blood pressure and peripheral oxygen saturation (SpO2). SCD patients had higher prevalence of severe anemia, jaundice and desaturation (SpO2 < 95%) as well as higher levels of reticulocytes, white blood cells, platelets and fetal hemoglobin. The main causes of hospitalization for SCD within a 12-month period preceding enrolment were pain (adults), and fever and severe anemia (children). When clinical and laboratory features were compared in SCD within 3 age groups, there was a progressive decrease in the prevalence of splenic enlargement and an increase in prevalence of jaundice. Furthermore, there were significant differences with monotonic trends across age groups in SpO2, hematological and biochemical parameters. Conclusion: This report confirms that the wide spectrum of clinical expression of SCD observed elsewhere is also present in Tanzania, with non-uniform geographical distribution across the country. Age-specific analysis is consistent with different disease-patterns across the lifespan

Reduction of anti-malarial consumption after rapid diagnostic tests implementation in Dar es Salaam: a before-after and cluster randomized controlled study

ABSTRACT: BACKGROUND: Presumptive treatment of all febrile patients with anti-malarials leads to massive over-treatment. The aim was to assess the effect of implementing malaria rapid diagnostic tests (mRDTs) on prescription of anti-malarials in urban Tanzania. METHODS: The design was a prospective collection of routine statistics from ledger books and cross-sectional surveys before and after intervention in randomly selected health facilities (HF) in Dar es Salaam, Tanzania. The participants were all clinicians and their patients in the above health facilities. The intervention consisted of training and introduction of mRDTs in all three hospitals and in six HF. Three HF without mRDTs were selected as matched controls. The use of routine mRDT and treatment upon result was advised for all patients complaining of fever, including children under five years of age. The main outcome measures were: (1) anti-malarial consumption recorded from routine statistics in ledger books of all HF before and after intervention; (2) anti-malarial prescription recorded during observed consultations in cross-sectional surveys conducted in all HF before and 18 months after mRDT implementation. RESULTS: Based on routine statistics, the amount of artemether-lumefantrine blisters used post-intervention was reduced by 68% (95%CI 57-80) in intervention and 32% (9-54) in control HF. For quinine vials, the reduction was 63% (54-72) in intervention and an increase of 2.49 times (1.62-3.35) in control HF. Before-and-after cross-sectional surveys showed a similar decrease from 75% to 20% in the proportion of patients receiving anti-malarial treatment (Risk ratio 0.23, 95%CI 0.20-0.26). The cluster randomized analysis showed a considerable difference of anti-malarial prescription between intervention HF (22%) and control HF (60%) (Risk ratio 0.30, 95%CI 0.14-0.70). Adherence to test result was excellent since only 7% of negative patients received an anti-malarial. However, antibiotic prescription increased from 49% before to 72% after intervention (Risk ratio 1.47, 95%CI 1.37-1.59). CONCLUSIONS: Programmatic implementation of mRDTs in a moderately endemic area reduced drastically over-treatment with anti-malarials. Properly trained clinicians with adequate support complied with the recommendation of not treating patients with negative results. Implementation of mRDT should be integrated hand-in-hand with training on the management of other causes of fever to prevent irrational use of antibiotic