Duplicate references removed.

Background
Tetralogy of Fallot is one of the critical congenital heart defects needing intervention within the first year of life.
Objective
This review aims to systematically assess the prevalence of Tetralogy of Fallot among children and adolescents with congenital heart defects in Sub-Saharan Africa from January 2000 to January 2024.
Methods
All original observational studies focused on children and adolescent population diagnosed with congenital heart defects within Sub-Saharan Africa; reported the primary outcome of interest were included. Prisma guidelines were utilized to perform this systematic review and meta-analysis. Electronic databases including Medline (PubMed), Scopus, Google Scholar, and African Index Medicus were searched. A weighted inverse variance random-effects model was employed to estimate the pooled prevalence of Tetralogy of Fallot.
Results
Thirty-one studies included encompassing a total of 11,265 participants from 15 Sub-Saharan African countries with representation from Southern (4 studies, 619 participants), Central (5 studies, 2,220 participants), Eastern (11 studies, 3,384 participants), and Western (11 studies, 5,042 participants). Cross-sectional studies comprised (25 studies, 8,909 participants), and cohort design (6 studies, 2,356 participants). The analysis revealed a pooled prevalence of 10% (95% CI: 9%; 12%) with I2 (77%, p-value < 0.01). The subgroup analysis based on geographic regions revealed statistically significant difference.
Conclusions and future implications
The prevalence of Tetralogy of Fallot observed was found considerably higher compared to global estimate and reports of developed countries. In a subgroup analysis based on the geographic region, a surprisingly high prevalence was reported across all regions of Sub-Saharan Africa. The substantial disparities and high prevalence observed underscores the complex interplay of factors influencing occurrence of Tetralogy of Fallot. Identifying the true scope of Tetralogy of Fallot burden may help policymakers and healthcare providers to prioritize interventions, optimize resource allocation, and potentially improve its outcomes in Sub-Saharan Africa.

背景
法洛四联症（Tetralogy of Fallot）是一类需要在出生后第一年内开展干预的危重先天性心脏病（congenital heart defects）。

研究目的
本综述旨在系统评估2000年1月至2024年1月期间，撒哈拉以南非洲（Sub-Saharan Africa）地区先天性心脏病患儿及青少年群体中法洛四联症的患病率。

研究方法
本系统综述与Meta分析严格遵循PRISMA指南（PRISMA guidelines）开展。纳入所有针对撒哈拉以南非洲地区确诊先天性心脏病的儿童及青少年人群的原创性观察性研究，且需报道目标主要结局指标。检索的电子数据库包括Medline（PubMed）、斯高帕斯数据库（Scopus）、谷歌学术（Google Scholar）以及非洲医学索引（African Index Medicus）。采用加权逆方差随机效应模型估算法洛四联症的合并患病率。

研究结果
最终纳入31项研究，共覆盖来自15个撒哈拉以南非洲国家的11265名研究对象，其中南部非洲区域4项研究（619名受试者）、中部非洲区域5项研究（2220名受试者）、东部非洲区域11项研究（3384名受试者）、西部非洲区域11项研究（5042名受试者）。纳入研究中，横断面研究25项（8909名受试者），队列研究6项（2356名受试者）。分析结果显示，法洛四联症的合并患病率为10%（95%CI：9%~12%），I²=77%，P值<0.01。基于地理区域的亚组分析显示，不同区域间的患病率差异具有统计学意义。

结论与未来展望
本研究观察到的法洛四联症患病率显著高于全球估算值及发达国家的相关报道。基于地理区域的亚组分析显示，撒哈拉以南非洲所有区域的法洛四联症患病率均处于较高水平。本次研究发现的显著疾病差异与高患病率，凸显了影响法洛四联症发生的多种因素间的复杂相互作用。明确法洛四联症疾病负担的真实规模，可为撒哈拉以南非洲地区的政策制定者与医疗服务提供者制定优先干预策略、优化资源配置，并潜在改善该病的诊疗结局提供科学依据。