Prevalence and predictors of microalbuminuria in Jamaican children with sickle cell disease.

OBJECTIVE: To determine the prevalence and predictors of microalbuminuria (MA) (urine albumin-creatinine ratios (ACRs) of 30-300 µg/mg) in children with homozygous sickle cell (Hb SS) disease in Jamaica. PATIENTS AND METHODS: 244 children with Hb SS disease were screened for MA. Blood samples and a retrospective review of patient records were used to determine haematological, biochemical and clinical correlates for MA. RESULTS: The prevalence of MA was 18.4%. The youngest child with MA was 2.8 years old. The distribution of urine ACRs was right skewed and normalised by natural log transformation. Abnormal urine ACRs ranged from 32 to 260 µg/mg. In univariable analyses with log ACR as outcome, ever having dactylitis (ß=0.44; 95% CI 0.08 to 0.80; p<0.02), glomerular hyperfiltration (ß=0.6; 95% CI 0.26 to 0.94; p<0.001), age (ß=0.07; 95% CI 0.01 to 0.12; p<0.02), estimated glomerular filtration rate (eGFR) (ß=0.01; 95% CI 0.005 to 0.02; p<0.001), haemoglobin concentration (ß=-0.18; 95% CI -0.34 to -0.02; p<0.03) and haemoglobin F (ß=-0.03; 95% CI -0.05 to -0.003; p<0.04) were significantly associated with MA but lactate dehydrogenase (a marker of haemolysis) was not. Adjusting for gender, age (ß=0.08; 95% CI 0.02 to 0.15; p=0.01), eGFR (ß=0.01; 95% CI 0.001 to 0.01; p=0.03) and body mass index (ß=-0.16; 95% CI -0.28 to -0.03; p=0.02) were predictors of MA. CONCLUSIONS: MA is seen as early as 2.8 years in children with sickle cell disease. Risk factors for MA include glomerular hyperfiltration, nutritional factors and vaso-occlusion but not haemolysis. Interventions addressing these factors may be useful.

Stroke recurrence in children with sickle cell disease treated with hydroxyurea following first clinical stroke.

Chronic transfusion therapy is the treatment of choice for preventing stroke recurrence in children with sickle cell disease (SCD). The majority of children affected by this devastating complication live in the developing world where access to regular blood transfusions may be impractical. Since 2000, in the absence of regular blood supplies, all children at the Sickle Cell Unit who had experienced a first clinical stroke were offered hydroxyurea (HU) as the only intervention to prevent stroke recurrence. Forty-four children were identified as having experienced a first clinical stroke between January 1, 2000 and September 30, 2009; one died at that presentation. Forty-three children were therefore followed for 111 person-years, of whom 10 (23.3%) agreed to start HU. Only one child in the HU group, incidence rate 2/100 person-years, had clinical stroke recurrence, compared to 20/33 in the non-HU group, incidence rate 29/100 person-years (Hazard ratio (HR) 9.4 [95% Confidence interval (CI): 1.3-70.6]; P = 0.03). When the groups were compared, in the non-HU group, four died (vs. zero), 13 (53% vs. 10%) had moderate-severe physical disability (P = 0.017), and 12 (44% vs. 20%) required special education or were too disabled to attend school. Our data support the role of HU as a useful intervention for prevention of stroke recurrence in SCD when transfusion programs are not available or practical.

Seizures in the Jamaica cohort study of sickle cell disease.

Although there is some evidence that epilepsy is more common in Sickle Cell Disease (SCD), we sought to establish the incidence rates, risk factors for and specific types of seizures in a SCD cohort followed from birth, and how seizure occurrence affects morbidity and mortality. We examined all records of persons in the Jamaica cohort Study of Sickle Cell Disease (JSSCD) clinically identified as having experienced a seizure during their lifetime. At first presentation, seizures were classified as Febrile Convulsion, Acute Symptomatic Seizure or Single Unprovoked Seizure. The seizure classification was revised to include Epilepsy if seizures recurred. Thirty-eight persons in the JSSCD (N = 543) were identified with seizures. The 5-year cumulative incidence of febrile convulsions was 2·2%. The incidence rate of epilepsy (all genotypes) was 100/100 000 person-years, 139/100 000 for the SS genotype. Despite limited availability of diagnostic investigations, clinical seizures were associated with increased all-cause mortality. Male gender (Odds Ratio [OR]: 4·0[95% confidence interval [CI]; 1·03-20·0]) and dactylitis in childhood (OR: 17·4 [95% CI; 4·82-62·85]) were associated with increased risk of developing epilepsy. Epilepsy in persons with SCD is 2-3 times more common than in non-sickle populations and is associated with increased all-cause mortality in all sickle cell genotypes.