[Screening for nephropathy in major sickle cell syndromes in patients monitored at the National Reference Center for Sickle Cell Disease in Niamey, Niger]

Abstract

Background: Sickle cell anemia is the most common hereditary hemopathy in the world. It is a disease that attacks all the systems of the organism. The kidneys are among the most sensitive organs of this disease. The main objective of this study is to detect sickle cell nephropathy in patients followed at the National Reference Center for Sickle Cell Disease in Niamey.

Methods: It is a prospective study carried out over a period of one year (January to December 2016). It included patients aged at least two years who had not had a vaso-occlusive crisis (VOC) for 2 months and not transfused for at least 3 months. A questionnaire was sent to each patient to collect demographic, clinical and biological information. Each patient provided a fresh blood and urine sample to assess biological parameters. We used Schwartz's formula in children and CKD-EPI in adults to assess glomerular filtration rate. The Pearson correlation coefficient (r) was used to assess the relationship between the different parameters under study. The threshold for statistical significance was set at 0.05.

Results: Two hundred and eighty participants were included in the study. Adolescents (≤17years) were 226 (80.71%) and adults were 54 (19.29%). The mean age of the patients was 11.94±4.70years. It was lower in SS subjects and higher in SC. The SS form accounted for 87.5% of the three sickle cell disease phenotypes encountered. The age group 6-15years was the most predominant (42.86%). The mean baseline hemoglobin in the sample was 7.59±1.15g/dL ; (6.8 ±0.9d/dL) in SS patients and higher (10.5±2.1g/dL) in SC patients. The average glomerular filtration rate was 201.04mL/min/1.73m². Glomerular hyperfiltration was found in 90% of the sample, it was lower (77.6%) in Sβ thalassemia patients (P=0.000). In young subjects hyperfiltration was present in 84.95% against it was observed in only 29.63% of adults. Proteinuria was positive in 20% of patients. Positive proteinuria was found in 6.20% pediatric cases. The SC form was the most affected and in 74.6% of the patients it was positive at 1+. Chronic kidney disease (CKD) was found in 10% of the participants, of whom 75% were of the SS phenotype. Sβ thalassemia subjects had no CKD. The male sex was predominant in subjects with CKD (P=0.000). Patients over 15 years of age accounted for more than 95% of patients in both forms of the disease (P=0.0001).

Conclusion: The SS form of the disease, recurrent vaso-occlusive crisis, male sex and advanced age were the main precipitating factors in the development of renal function disorders.

Keywords: Dépistage; Major sickle cell syndrome; Nephropathy; Niger; Néphropathie; Screening; Syndrome drépanocytaire majeur.