Nyawanda Bryan O, Mott Joshua A, Njuguna Henry N, Mayieka Lilian, Khagayi Sammy, Onkoba Reuben, Makokha Caroline, Otieno Nancy A, Bigogo Godfrey M, Katz Mark A, Feikin Daniel R, Verani Jennifer R
Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya.
BMC Infect Dis. 2016 May 21;16:218. doi: 10.1186/s12879-016-1532-0.
In order to better understand respiratory syncytial virus (RSV) epidemiology and burden in tropical Africa, optimal case definitions for detection of RSV cases need to be identified.
We used data collected between September 2009 - August 2013 from children aged <5 years hospitalized with acute respiratory Illness at Siaya County Referral Hospital. We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of individual signs, symptoms and standard respiratory disease case definitions (severe acute respiratory illness [SARI]; hospitalized influenza-like illness [hILI]; integrated management of childhood illness [IMCI] pneumonia) to detect laboratory-confirmed RSV infection. We also evaluated an alternative case definition of cough or difficulty breathing plus hypoxia, in-drawing, or wheeze.
Among 4714 children hospitalized with ARI, 3810 (81 %) were tested for RSV; and 470 (12 %) were positive. Among individual signs and symptoms, cough alone had the highest sensitivity to detect laboratory-confirmed RSV [96 %, 95 % CI (95-98)]. Hypoxia, wheezing, stridor, nasal flaring and chest wall in-drawing had sensitivities ranging from 8 to 31 %, but had specificities >75 %. Of the standard respiratory case definitions, SARI had the highest sensitivity [83 %, 95 % CI (79-86)] whereas IMCI severe pneumonia had the highest specificity [91 %, 95 % CI (90-92)]. The alternative case definition (cough or difficulty breathing plus hypoxia, in-drawing, or wheeze) had a sensitivity of [55 %, 95 % CI (50-59)] and a specificity of [60 %, 95 % CI (59-62)]. The PPV for all case definitions and individual signs/symptoms ranged from 11 to 20 % while the negative predictive values were >87 %. When we stratified by age <1 year and 1- < 5 years, difficulty breathing, severe pneumonia and the alternative case definition were more sensitive in children aged <1 year [70 % vs. 54 %, p < 0.01], [19 % vs. 11 %, p = 0.01] and [66 % vs. 43 %, p < 0.01] respectively, while non-severe pneumonia was more sensitive [14 % vs. 26 %, p < 0.01] among children aged 1- < 5 years.
The sensitivity and specificity of different commonly used case definitions for detecting laboratory-confirmed RSV cases varied widely, while the positive predictive value was consistently low. Optimal choice of case definition will depend upon study context and research objectives.
为了更好地了解呼吸道合胞病毒（RSV）在热带非洲的流行病学特征和疾病负担，需要确定检测RSV病例的最佳病例定义。
我们使用了2009年9月至2013年8月期间在锡亚亚县转诊医院因急性呼吸道疾病住院的5岁以下儿童的数据。我们评估了个体体征、症状和标准呼吸道疾病病例定义（严重急性呼吸道疾病[SARI]；住院流感样疾病[hILI]；儿童疾病综合管理[IMCI]肺炎）检测实验室确诊的RSV感染的敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）。我们还评估了咳嗽或呼吸困难加缺氧、吸气凹陷或喘息的替代病例定义。
在4714名因ARI住院的儿童中，3810名（81%）接受了RSV检测；470名（12%）呈阳性。在个体体征和症状中，仅咳嗽对检测实验室确诊的RSV敏感性最高[96%，95%置信区间（95 - 98）]。缺氧、喘息、喘鸣、鼻翼扇动和胸壁吸气凹陷的敏感性范围为8%至31%，但特异性>75%。在标准呼吸道病例定义中，SARI敏感性最高[83%，95%置信区间（79 - 86）]，而IMCI重症肺炎特异性最高[91%，95%置信区间（90 - 92）]。替代病例定义（咳嗽或呼吸困难加缺氧、吸气凹陷或喘息）的敏感性为[55%，95%置信区间（50 - 59）]，特异性为[60%，95%置信区间（59 - 62）]。所有病例定义和个体体征/症状的PPV范围为11%至20%，而阴性预测值>87%。当我们按年龄<1岁和1 - <5岁分层时，呼吸困难、重症肺炎和替代病例定义在<1岁儿童中更敏感[70%对54%，p < 0.01]、[19%对11%，p = 0.01]和[66%对43%，p < 0.01]，而非重症肺炎在1 - <5岁儿童中更敏感[14%对26%，p < 0.01]。
检测实验室确诊的RSV病例时，不同常用病例定义的敏感性和特异性差异很大，而阳性预测值始终较低。病例定义的最佳选择将取决于研究背景和研究目标。
