The Trend of Paediatric Burkitt’s Lymphoma Admissions Over Last Three Decades (1990-2020) and Changes With Changing Malaria Admissions in the Coastal Region of Kenya

Abstract

Introduction Burkitt’s lymphoma (BL) is a non-Hodgkins lymphoma that may account for 40-60% of all childhood malignancies in tropical Africa. Several varieties of this malignancy have been described: endemic, sporadic, and immune deficiency associated. The endemic version is common in equatorial Africa where a BL belt has been mapped from East to West Africa between 10 degrees north to 10 degrees south of the equator and continues along the Eastern Africa Coast. Co-infection with the two plausible predisposing factors, (Plasmodium Falciparum Malaria and Epstein Barr virus) are thought to prevail in this region. Changing malaria epidemiology may have an effect on the burden of BL but this has not been studied comprehensively in any of the countries within the endemic BL belt. Objective In this study, we examined the trends of admitted cases, as well as annual admission incidence rates of Burkitt’s lymphoma expressed as annual admission incidence rates per 100,000 admissions over three decades (1990-2020), and outlined changes with changing malaria admissions. Design A retrospective longitudinal study Setting This study was conducted using data collected from Kilifi County Referral Hospital, in the coastal region of Kenya. 2 Subjects This study primarily utilized data from all children and adolescent aged 0-14yrs with a final discharge diagnosis of Burkitt’s lymphoma from the study site as well as all children with a final diagnosis of Malaria. To compute the annual admission incidence rates, all children aged 0-14years were used. Method This study utilized data already collected from the participants at the point of admission and discharge and entered into secure databases at the study site. The data included clinical parameters, final diagnosis as well as laboratory investigations. Secondary anonymized data of all the participants meeting the inclusion criteria were initially exported to Excel or other appropriate format and then imported into STATA (Stata Corp, College Station, TX, USA) for final analysis. Incidence rates (per 100,000 admission per year) were calculated. To address the effect of chance fluctuations in our analysis model, regression models were applied. Equally, the initial model output was controlled for at risk population estimated from the catchment population and the final output further controlled for trends in annual admissions that were positive malaria cases. The study was approved by Kenyatta National Hospital- University of Nairobi scientific and ethics review committee (KNH-UON ERC), approval number P298/04/2022. The data governance committee at the Kenya Medical Research Institute (KEMRI) further authorized the use of the data from the study site. 3 Results The total admissions for the entire period from 1990 to 2020 was 124,298 of which 69,468(56%) were males and 54,830(44%) females. The trend in total pediatric admissions (0-14 years) remained largely unimodal peaking in 2003 with 5,459 admissions per year and having its nadir of just 2187 admissions in 2017. The proportion of admissions testing positive for malaria as well as the malaria parasite density was highest in the first ten-year-period (1990 to 1999). Thereafter, both the positivity fraction and the parasite density significantly decreased (p<0.0001). From the admission records, 95 cases of Burkitt’s lymphoma were identified, of whom 72 (76%) were male and 23 (24%) were female. The incidence BL controlled for the estimated population at risk was 4.8 cases per 100,000 in the mid-1990s dropping to a low of 0.2 cases per 100,000 in 2020. The declining trend over the decades was significant (p=0.03). Further, the relationship over time, between the proportion of children testing positive for malaria at admission, parasite density and Burkitt’s lymphoma was explored using a Poisson regression approach. The coefficient was -0.2971 (p<0.0001), reflecting to a reduction in 0.2 cases per 100,000 for every unit increase in years. Conclusion There has been a significant reduction in the annual incidence rates of Burkitt’s lymphoma in the coastal region of Kenya. It’s plausible that this decrease is explained by an equally sustained significant decline in prevalence of Falciparum malaria infection in the region. Our study findings provide important insight into possible interlinkage and effect of control measures of these two diseases entities of public health importance. 4 Further studies should explore if the similar declines are been documented across other regions within the endemic BL belt