Published in PLOS One on 2026-04-06, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. HealthSignal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Zawadi Edward Kalezi, Jimmy France Mchalange, Naizihijwa Gadi Majani, Alphonce Nsabi Simbila, Vivienne Aiyana Mlawi, Deogratias Arnold Nkya, Peter Richard Kisenge
Source: PLOS One • DOI 10.1371/journal.pone.0345457
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
The World health organization (WHO) identifies Down syndrome (DS) as one among common congenital disorders, along with congenital heart defects. Approximately fifty percent of children diagnosed with DS are affected by congenital heart defects which significantly impact their survival. Nevertheless, in low and middle income countries, there is limited published data on congenital heart defects in children with DS and their treatment outcomes. Therefore, this study aimed to document the clinical characteristics and hospital outcomes of children with DS who were diagnosed with heart defects. The goal is to assist healthcare providers and policymakers in improving care for these children.
This was a retrospective descriptive study of children with DS diagnosed with heart disease admitted at the Jakaya Kikwete Cardiac Institute (JKCI) from December 2022 through December 2024. Socio-demographics, clinical characteristics, and survival data were extracted from medical records. Frequencies and proportions were calculated for categorical variables. The description of mean with standard deviation (SD) and median with and interquartile range (IQR) were calculated for continuous data. For the missing data, the case deletion approach was used.
In two years, out of 1,356 admitted children, data from 104 children with Down syndrome were analysed. Most of them, 93.2%, were aged below 5 years, with a slight predominance of male children, of almost 58%. Fifty percent (58/104) of study participants resided in the coastal region of Tanzania, followed by the northern zone (19.2%, 20/104). The most frequent cardiac diagnoses were AVSD, 46.2% and VSD, 14.4% with a median age at diagnosis of 5 months (IQR, 3.3–10). The median age of the mothers was 38 years (IQR, 38–42) while the mean age of the fathers was 36.9 years (SD, ± 7.1). At discharge, nearly a quarter, 19.2% of children had prolonged hospital stays of more than 2 weeks, and 7.7% (8/104) of enrolled children died. Nevertheless, 4.8% of children with Down syndrome underwent open cardiac surgery during the study period.
Advanced maternal age, paternal age and AVSD were frequently observed in this study, nevertheless; a significant number of the enrolled children were first diagnosed beyond 5 months of age. Hence, the study recommends early screening echocardiography among children with Down syndrome and more studies with a large sample size to evaluate long-term outcomes in this population.
Background
Down syndrome (DS) is one of the most common chromosomal disorders with an incidence of approximately 1 in 733 live births [1]. A population-based study in the USA, estimated the live birth prevalence for DS to be approximately 12.6 per 10,000 (1 in 792) in the era of DS-related elective pregnancy terminations [2]. Despite limited studies in developing countries, the prevalence of DS is reported to be higher compared to developed settings. However, this is contrary to what was reported in the 1990s. This could be attributable to many factors including advanced maternal age at birth, elective DS-related pregnancy terminations following prenatal diagnosis, and traditional beliefs [3,4].
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider research & evidence desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2026 Zawadi Edward Kalezi, Jimmy France Mchalange, Naizihijwa Gadi Majani, Alphonce Nsabi Simbila, Vivienne Aiyana Mlawi, Deogratias Arnold Nkya, Peter Richard Kisenge. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by HealthSignal. The researchers are the authors of the source study, not members of HealthSignal’s staff.
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