Justine Busanga Bukabau

Sickle cell disease (SCD) is the most common monogenic hemoglobinopathy worldwide, affecting approximately 300,000 newborns annually, with the highest burden in sub-Saharan Africa, India, the Middl...

Sickle cell disease (SCD) is one of the most common haemoglobinopathies worldwide, with nearly 300,000 newborns affected each year, of which about 80% are born in sub-Saharan Africa [1,2]. In the D...

Background and Objectives: On-line hemodiafiltration (OL-HDF) has been proposed as an alternative to conventional hemodialysis (HD) for patients with end-stage chronic kidney disease (CKD). Randomized controlled trials suggest that OL-HDF may reduce mortality, particularly when the convection volume (CV) exceeds 23 L/1.73 m² per session. However, achieving this target depends on local practices and may be limited to selected populations. The CONVINCE trial reported a 97% success rate using a structured optimization protocol, but its applicability to unselected real-world populations remains uncertain. This study aimed to evaluate the incidence of high CV in OL-HDF among unselected patients managed under routine conditions with a standardized optimization protocol. Methods and Materials: This prospective cohort study (May–October 2024) included 67 unselected incident and prevalent patients undergoing HD or HDF in a hospital-based dialysis center. All patients were switched to post-dilution OL-HDF following the CONVINCE optimization protocol, which involved stepwise increases in blood flow, adjustment of filtration fraction, and optimization of session duration. Results: The mean age was 68.8 ± 14.9 years; 56.7% were male. Blood flow increased from 283 to 338 mL/min (p < 0.001), and the use of dialyzers > 2 m² increased from 36% to 68% (p < 0.003). Kt/V improved from 1.22 to 1.6 (p < 0.01). CV increased by ~2 L from M1 onward and was sustained through M6, correlating positively with blood flow, session duration, and Kt/V (all p < 0.01). Conclusions: Stepwise optimization protocol enabled sustained achievement of high CV (23.5 L/session) in 62.3% of patients, improving dialysis adequacy.

Despite current interest in creatinine-based equations for estimating glomerular filtration rate, the evaluation of creatinine reference intervals remains relevant. The present study aimed to establish such reference intervals from a healthy Congolese adult population and to investigate the determinants of serum creatinine. This study was based on post-hoc data of previous epidemiology studies conducted in the general population of Kinshasa. Serum Creatinine measurement was performed with the Roche Cobas (Roche Diagnostics, Mannheim, Germany) enzymatic method calibrated to Isotope Dilution Mass Spectrometry (IDMS) traceable. The creatinine values being not normally distributed, the median values and interquartile range and the 2.5th and 97.5th percentiles were considered. Serum creatinine determinants were investigated by a generalized linear model (GLM). A value of p < 0.05 was the threshold of statistical significance. Of 2,504 Congolese adults screened, 506 (males, 67.7%) were healthy and were involved in this study. Their mean body surface area (BSA) was 1.64 ± 0.15 m2. In males, the median of creatinine was 0.96 [0.87; 1.05] mg/dl and percentiles 2.5th and 97.5th were 0.65 and 1.22 mg/dL, respectively. The reference intervals were between 0.65 (90% confidence interval (CI): 0.63 to 0.67) and 1.22 (90% CI: 1.20 to 1.24) mg/dL for the lower limits (LL) and the upper limits (UL), respectively. In females, the median of creatinine was 0.72 [0.66; 0.80] mg/dl and percentiles 2.5th and 97.5th were 0.50 and 0.95 mg/dL, respectively. The reference intervals were between 0.50 (90%CI: 0.47 to 0.52) and 0.95 (90% CI: 0.93 to 0.98) mg/dL for the lower and the upper limits respectively. The factors independently associated with serum creatinine were age, female gender, the interaction between age and gender, weight, arm circumference, education level, and weekly walking frequency. The reference intervals for serum creatinine for Congolese adults seem close to those of White Europeans, with slightly higher values in Congolese compared to Caucasians, but lower than those of the African-Americans. Constitutional factors and lifestyle impact serum creatinine levels.

Background Serum creatinine (SCr), the most used biomarker to evaluate glomerular filtration rate (GFR), might be inaccurate in children with sickle cell anemia (SCA). In this context, cystatin C (SCys) could be of interest. This study evaluated the performance of commonly used SCr- and SCys-based estimated GFR (eGFR) equations in African children with SCA. Methods This cross-sectional study included 109 steady-state children with SCA aged 3–18 years, from the Democratic Republic of Congo. Measured GFR (mGFR) was obtained using iohexol plasma clearance. eGFR was calculated using commonly used SCr- and SCys-based equations in children. The performance of these equations was evaluated by calculating the bias, precision, and accuracy within 30% (P30) of mGFR. Results The mean age of participants was 9.9 ± 4.2 years, and 48.6% were female. The median mGFR was 142 (IQR 119–169) mL/min/1.73 m². Of the equations studied, the FAS-Age SCr had the lowest bias (0.9 mL/min/1.73 m²). However, the 95% limit of agreement was very wide (−80.3 to + 81.6). SCr failed to rise in an age-dependent manner, reflecting a progressive loss of muscle mass or increased tubular secretion. All SCys-based equations underestimated GFR and failed to detect hyperfiltration, but there was no age-related change in bias. Conclusion These data show that all common eGFR equations using SCr or SCys poorly predict mGFR in African children with SCA. SCr-based equations potentially miss a decline in kidney function, which suggests that SCys could be the preferred marker in this population. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information

Background The Schwartz equation is the most widely used serum creatinine (SCr)-based formula to estimate the glomerular filtration rate (GFR) in children of European descent, but whether this applies to African children is unclear. Methods In a cross-sectional study, 513 apparently healthy African children aged 6 to 16 years were randomly recruited in school area of Kinshasa, the Democratic Republic of Congo (DRC). SCr was measured using calibrated enzymatic method. SCr was normalized using Q-values designed for European descent children, due to the absence of Q-values for African children. Commonly used eGFR equations were applied in this population. Results Normalization of SCr using Q-values for European descent children was effective in this cohort. The majority of African children (93.4%) have normalized SCr (SCr/Q) values within the reference interval (0.67–1.33) of children of European descent. The bedside-Schwartz equation was associated with significant age and sex dependency. However, the FAS-Age formula showed no sex and age dependency. The new CKiDU25 equation did not show a significant sex dependency. The recently introduced EKFC and LMR18 equations also showed no age and sex dependency, although the distribution of eGFR-values was not symmetrical. On the other hand, the FAS-Height and the Schwartz-Lyon equations showed significant sex dependency but no age dependency. Conclusions The reference interval for SCr designed for European descent children can be applied to African children. Of all the equations studied, FAS-Age performed best and is most suitable because no height measurements are required. Establishment of specific Q-values for the widespread Jaffe-measured creatinine in Africa can further broaden applicability. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information

Introduction: Contexte : bien que le débit de filtration glomérulaire (DFG) soit essentiel dans le diagnostic, l’adaptation posologique et le suivi de la maladie rénale chronique (MRC), l’applicabilité des équations d’estimation reste discutable. Cette étude vise à évaluer la performance des différentes équations d’estimation du DFG chez l’adulte en Afrique Sub-saharienne. Patients/Matériels et méthodes Méthode : étude transversale réalisée dans les populations adultes de Kinshasa en RDC et d’Abidjan en Côte d’Ivoire, ayant bénéficié d’une mesure du DFG par une technique de référence : DFG mesuré (DFGm) (clairance de l’iohexol en 4 points) versus le DFG estimé (DFGe) par les équations MDRD, CKD-EPI, Full Age Spectrum (FAS), Lund-Malmö (LM), Caucasian, Asian, Paediatric and Adult (CAPA), LM + CAPA. Les différentes équations étaient basées sur la créatinine (SCr) et/ou la cystatine C (Cys). Les équations avec un facteur correctif ethnique ont été étudiées avec et sans cette correction. L’équation FAS a été utilisée avec le facteur Q caucasien ou africain. La créatinine enzymatique et la cystatine C étaient standardisées. Les critères de performance utilisés étaient le biais, la précision et l’exactitude à 30 % (P30). Observation/Résultats Résultats : l’étude a porté sur 510 participants Congolais (n = 222) et Ivoiriens (n = 288). Le DFGm médian était de 92 mL/min/1,73 m² (âge médian : 49 ans, 47 % de femmes). AU total, 416 sujets avaient un DFGm supérieur à 60 mL/min/1,73 m² et 94 un DFGm inférieur. Les équations sans facteurs ethniques avaient une meilleure exactitude qu’avec facteur ethnique, surtout dans la population saine. L’équation FAS était la meilleure équation avec un biais de −6 ± 19 mL/min/1,73 m² pour l’équation avec le Q caucasien et de −2 ± 20 mL/min/1,73 m² avec le Q africain. Les deux avaient une P30 à 80 %. Concernant la cystatine C, FAS Cys était la meilleure équation avec un biais faible (0 ± 18 mL/min/1,73 m²) et une meilleure exactitude (P30 = 86 %). Chez les sujets avec un DFGm < 60 mL/min/1,73 m², toutes les équations avaient des mauvaises performances avec des P30 < 50 %. Seule l’équation FAS Cys se détachait avec une P30 à 67 %. Discussion/Conclusion En Afrique Sub-Saharienne, l’équation FAS basée sur la créatinine et/ou la cystatine C est la plus performante. Toutes les équations basées sur la créatinine ont une faible performance pour estimer un DFGm < 60 mL/min/1,73 m². La cystatine C améliore la performance des équations surtout dans le groupe avec MRC (tout en restant sub-optimale dans ce groupe).

In the estimation of glomerular filtration rate (GFR), ethnicity is an important determinant. However, all existing equations have been built solely from Caucasian and Afro-American populations and they are potentially inaccurate for estimating GFR in African populations. We therefore evaluated the performance of different estimated GFR (eGFR) equations in predicting measured GFR (mGFR). In a cross-sectional study, 93 healthy adults were randomly selected in the general population of Kinshasa, Democratic Republic of the Congo, between June 2015 and April 2016. We compared mGFR by plasma clearance of iohexol with eGFR obtained with the Modified Diet in Renal Disease (MDRD) equation with and without ethnic factor, the Chronic Kidney Disease Epidemiology (CKD-EPI) serum creatinine (SCr)-based equation, with and without ethnic factor, the cystatin C-based CKD-EPI equation (CKD-EPI SCys) and with the combined equation (CKD-EPI SCrCys) with and without ethnic factor. The performance of the equations was studied by calculating bias, precision and accuracy within 30% (P30) of mGFR. There were 48 women and 45 men. Their mean age was 45.0±15.7 years and the average body surface area was 1.68±0.16m². Mean mGFR was 92.0±17.2 mL/min/1.73m² (range of 57 to 141 mL/min/1.73m²). Mean eGFRs with the different equations were 105.5±30.1 and 87.2±24.8 mL/min/1.73m² for MDRD with and without ethnic factor, respectively; 108.8±24.1 and 94.3x20.9 mL/min/1.73m² for CKD-EPI SCr with and without ethnic factor, respectively, 93.5±18.6 mL/min/1.73m² for CKD-EPI SCys; 93.5±18.0 and 101±19.6 mL/min/ 1.73m² for CKD-EPI SCrCys with and without ethnic factor, respectively. All equations slightly overestimated mGFR except MDRD without ethnic factor which underestimated by -3.8±23.0 mL/min /1.73m². Both CKD-EPI SCr and MDRD with ethnic factors highly overestimated mGFR with a bias of 17.9±19.2 and 14.5±27.1 mL/min/1.73m², respectively. There was a trend for better P30 for MDRD and CKD-EPI SCr without than with the ethnic factor [86.0% versus 79.6% for MDRD (p = 0.21) and 81.7% versus 73.1% for the CKD-EPI SCr equations (p = 0.057)]. CKD-EPI SCrCys and CKD-EPI SCys were more effective than creatinine-based equations. In the Congolese healthy population, MDRD and CKD-EPI equations without ethnic factors had better performance than the same equations with ethnic factor. The equations using Cys C (alone or combined with SCr) performed better than the creatinine-based equations.