EPIDEMIOLOGIC FEATURES OF ACUTE APPENDICITIS IN A TROPICAL AFRICAN POPULATION

<b>BACKGROUND:</b> The true incidence rate of appendicitis in Cameroon and the magnitude of etiological factors in appendicitis are unknown. <b>AIM:</b> To describe the epidemiology of acute appendicitis in the Northwestern region of Cameroon. <b>MATERIALS AND METHODS:</b> A retrospective population-based cohort study was conducted to assess the demographic features, incidence and seasonal variation of acute appendicitis using the medical database of two Mission Hospitals in the Northwestern Region, Cameroon from January 2006 to January 2016. The National Institute of Statistics, <em>Bamenda Regional Office</em><i>,</i> Bui-Division -Population Data of Cameroon in 2016 was used to estimate the standardized annual incidence of appendicitis in the locality. Hospital A is a 200-bed Mission Hospital (with 50 surgical beds), while Hospital B is a 250-bed Mission Hospital (with 70 surgical beds). Pathologically confirmed specimens of appendicitis were analyzed against demographic data of the patients. Data analysis was done using simple percentages, Student t or Chi-square tests and calculations were also aided with the Number Cruncher Statistical (NCSS, LLC Kaysville) software where applicable.<br> <b>RESULTS:</b> During the decade, a total of 772 out of 784 cases of appendicitis recorded during the observed period were confirmed histologically from both hospitals (56% from Hospital A and 44% from Hospital B). With a local population whose disease or specimens would most probably end up in this hospital pathology department estimated at 1,753,460 the standardized incidence rate of appendicitis was 3.85 per 100,000 per annum. Fifty-two percent were males and 48% were females. The appendicitis cases were made up 0.94%, 1.53%, and 2.86% of the total hospital admissions in 2006, 2007, and 2010, respectively. There has been an increasing incidence in both sexes almost in a similar pattern. The overall mean age was 28.64 years (M 28.94 and F 28.43 years) with 6% below the age of ten and 1.5% above 60 years. The highest incidence in males and females occurred in the second and third decades, respectively. Incidences were higher during the rainy season (April to September) 68%, P &lt; 0.05), with peaks from June to August, when 42.5% of all cases presented. <b>CONCLUSION:</b> Appendicitis is very uncommon in northwest Cameroon. The increasing incidence of the disease in both sexes in this region may be due to the change to a Western lifestyle. The age distribution has a similar pattern in both sexes and 85% are 40 years or less, although the incidence is marginally higher in males. Higher prevalence of infections and allergens from pollens in the rainy season could contribute to a higher incidence of appendicitis.

**背景**：目前尚不清楚喀麦隆地区阑尾炎（appendicitis）的真实发病率，以及阑尾炎相关致病因素的影响程度。
**目的**：旨在描述喀麦隆西北部地区急性阑尾炎（acute appendicitis）的流行病学特征。
**材料与方法**：本研究于2006年1月至2016年1月期间，依托喀麦隆西北部地区两家教会医院的医疗数据库开展回顾性人群队列研究，以评估急性阑尾炎的人口统计学特征、发病率及季节变化规律。本研究使用2016年喀麦隆布伊大区国家统计研究所班达地区办公室（Bamenda Regional Office）的人口统计数据，估算当地阑尾炎的标准化年发病率。医院A为拥有200张床位的教会医院（其中外科床位50张），医院B为拥有250张床位的教会医院（其中外科床位70张）。研究对经病理学确诊的阑尾炎标本与患者的人口统计学数据进行关联分析。数据分析采用简单百分比法、Student t检验或卡方（Chi-square）检验，必要时借助Number Cruncher Statistical（NCSS, LLC Kaysville）软件完成相关计算。
**结果**：在本次观察的十年间，两家医院记录的784例阑尾炎病例中，共有772例经组织病理学确诊（其中医院A占56%，医院B占44%）。以当地预计会将疾病诊疗或标本送检至该医院病理科的1,753,460人口为基数，阑尾炎的标准化年发病率为每10万人3.85例。患者中男性占52%，女性占48%。2006年、2007年及2010年，阑尾炎病例分别占全院总住院人次的0.94%、1.53%及2.86%。两性的发病率均呈上升趋势，且变化模式基本一致。研究对象的总平均年龄为28.64岁（男性平均28.94岁，女性平均28.43岁），其中6%的患者年龄低于10岁，1.5%的患者年龄超过60岁。男性与女性的发病高峰分别集中在第二、第三个十年年龄段（即20~29岁与30~39岁）。雨季（4月至9月）的阑尾炎发病率更高，占总病例数的68%（P<0.05），发病高峰集中在6月至8月，该时段的病例数占总病例的42.5%。
**结论**：阑尾炎在喀麦隆西北部地区较为罕见。该地区两性阑尾炎发病率均呈上升趋势，这可能与西方生活方式的普及有关。尽管男性发病率略高于女性，但两性的年龄分布模式相似，85%的患者年龄在40岁及以下。雨季中花粉来源的感染原与过敏原的流行率更高，可能是导致阑尾炎发病率升高的潜在原因之一。