【摘要】目的对呼吸道合胞病毒(RSV)感染的住院儿童的感染程度与危险因素进行相关分析。方法（1）选择综合指标严重指数(SI)对122例确诊为RSV感染的0～1岁的患儿进行RSV感染严重程度的评价，SI≥3者为重症感染；（2）设预期潜在性疾病、年龄≤3个月和早产为RSV重症感染的危险因素，根据有无危险因素将122例住院患儿划分为高危组和低危组；（3）对感染程度与危险因素进行相关分析。结果（1）以早产和年龄≤3个月作为危险因素，高危组71例，SI≥3者明显超过低危组(P＜0.05)；（2）以潜在性疾病和年龄≤3个月，或以早产和潜在性疾病作为危险因素，高危组分别为69例和17例，SI≥3者略多于低危组，但差异无显著意义；（3）多因素Logistic分析显示，早产、年龄≤3个月与重症感染呈显著正相关 (r=0.248 7、0.194 5, P＜0.05、0.001)，潜在性疾病与重症感染无关(P＞0.05)。（4）经回归方程计算，早产儿感染RSV后50.7%有可能发生重症感染，非早产儿感染后仅2.2%可能发生重症感染(P=0.012)。年龄≤3月龄、潜在性疾病等因素进入回归方程计算均无显著意义。结论RSV感染严重程度与早产、年龄≤3个月密切相关，二者是重症感染的危险因素，且早产是重症感染的预示指标；而潜在性疾病不是重症感染的危险因素。

Correlation between illness severity and risk factors for respiratory syncytial virus infection

KONG XiaohuiLIU ChunyanSHOU Haochang

（Beijing Children's Hospital Affiliated to Capital University of Medical Sciences, Beijing 100045, China）

【Abstract】ObjectiveTo evaluate respiratory syncytial virus (RSV) infection accurately, effectively and objectively, and explore relationships between illness severity and risk factors. MethodsEpidemiologic and clinical data were collected within 24 hours after admission for 122 infants under 1 year of age who were hospitalized to Beijing Children's Hospital with lower respiratory tract infection caused by RSV during the period from Nov., 1997 to May, 1998. Severity index (SI) was chosen as a comprehensive index to evaluate illness severity of RSV infection, which was defined as scores of sI≥3. Underlying conditions, age≤3 months, and prematurity were expected to be risk factors for severe disease. With or without the presence of these risk factors, 122 hospitalized infants were classified as high and low risk groups and analysis of correlation between illness severity of RSV infections and risk factors was made respectively. ResultsWith prematurity or age≤3months being used as risk factor, higher severity scores were noted in high risk group subjects than in low risk group subjects (median 1.0 vs 0, mean ranks 70.8 vs 48.6，z score=-3.71，P＜0.001) , a significantly greater proportion of the infants of high risk group than those of low risk group had a SI≥3(P＜0.05). With underlying conditions or age≤3 months as a risk factor, the proportion of high risk group infants who had a SI≥3 was slightly more than that of low risk group infants (P＞0.05), although the SI distribution was higher among high risk group infants (median 1.0 vs 0, mean ranks 71.3 vs 48.9, z score=-3.8, P＜0.001). With prematurity or underlying conditions being taken as a risk factor, both SI scores and the proportions of the infants who had a SI≥3 were not significantly different between high and low risk groups (median 1.0 vs 0, mean ranks 73.6 vs 59.5, z score=-1.7, P＞0.05; RR=2.8, P＞0.05). Multivariate Logistic analysis (goodness-of-fit χ² statistic=12.6, df=2, P=0.002) indicated that prematurity and age≤3 months were each independently and strongly associated with increased risk of severe illness(P＜0.05, P＜0.001), while underlying conditions was not statistically related to severity of illness (P＞0.05).Also,prematurity was marginally significant as a predictor of severity (P＜0.05). For infants with the risk factor of prematurity, the model predicted that 50.7% would have severe disease. ConclusionsThese observations suggest that certain factors are associated with severe disease during RSV infection. Foremost among these are prematurity and age≤3 months, which were both risk factors for severe illness. In addition, prematurity was a predictor of severity. Underlying conditions might not be a risk factor for severe disease.

【Key words】Respiratory syncytial virus infections；Bronchiolitis, viral；Pneumonia, viral;Child

呼吸道合胞病毒（RSV）是婴幼儿下呼吸道感染的主要病原。某些宿主因素与初次RSV感染的严重程度有关^［1］。在这些因素中，最重要的是年龄≤3个月、早产、潜在性疾病、免疫力低下等。目前，国外对RSV感染程度的评价尚无统一的方法，影响RSV感染严重程度的因素存在着各种争议^［2-4］。我国儿科尚无此方面的报道。本研究通过回顾122例RSV感染的住院婴儿的临床特点，选择了临床综合指标评价RSV的感染程度，并就与之相关的因素进行了探讨。

对象及方法

一、 对象

从北京儿童医院1997年11月～1998年5月310例下呼吸道感染住院患儿中检测出的0～1岁RSV下呼吸道感染住院患儿，毛细支气管炎和肺炎诊断均符合《实用儿科学》诊断标准^［5］，共122例，年龄0.4～11.8个月,平均（4.0±2.9）个月，男83例，女39例。RSV感染用鼻咽洗液间接免疫荧光抗体检测确定。

二、方法

1．临床资料收集：收集上述研究对象的流行病学以及住院后24小时内的临床和实验室检查资料，包括性别、种族、胎龄、入院时年龄、变应性疾病家族史、既往喘息病史、母乳喂养史、潜在性疾病、诊断、一般临床特点（发热、咳嗽、喘憋、水泡音、喘息、喘鸣、三凹征或紫绀、呼吸暂停），记录生命指征、吸氧、机械通气、外周血象和血气分析值、胸部X线表现和住院天数。研究中去除了先天性心脏病患儿的SaO₂值。资料收集是在尚未明确RSV感染的情况下进行的，避免了偏差。

2．感染严重程度的评估：参照文献^［1,2］，选择严重指数(severity index，SI)作为评估RSV感染严重程度的综合指标。SI由以下几个因素确定：住院期间出现呼吸暂停、pH＜7.35、PCO₂＞45 mmHg、SaO₂＜87%、住院天数＞13 d等因素各计1分，使用机械通气计2分。SI≥3者设定为重症感染。122例RSV下呼吸道感染住院患儿中SI≥3者23例，SI＜3者99例。

3．以危险因素分组：预期有潜在性疾病、年龄≤3个月或早产的患儿RSV感染程度较重，因而，将三者定为危险因素(risk factor)^［1,2］，其中潜在性疾病是指先天性心脏病、支气管肺发育不良、囊性纤维化、曾经诊断为哮喘、免疫低下(白血病、Down综合征、镰刀细胞贫血等)、神经性或吞咽困难(脑性瘫痪、胃食管返流、声门下血管瘤等)^［1］。根据有无危险因素将122例RSV感染患儿划分为高危组和低危组：（1）以早产和年龄≤3个月做为危险因素，高危组71例，低危组51例；（2）以年龄≤3个月和潜在性疾病做为危险因素，高危组69例，低危组53例；（3）以早产和潜在性疾病做为危险因素，高危组17例，低危组105例。

4．分析感染程度与危险因素的相关性：分别比较以（1）早产和年龄≤3个月、（2）年龄≤3个月和潜在性疾病和（3）早产和潜在性疾病做为危险因素时，高、低危组感染程度的差异有无显著意义，并对有感染程度与危险因素进行相关性分析。

5．统计学处理方法：数据均采用spss for Windows 8.0统计软件包处理。组间差异比较记数资料采用χ²检验、计量资料采用Student' t检验，组间差异有显著性的变量进入Logistic回归分析，非正态分布资料采用Mann-Whitney秩和检验。

结果

一、RSV感染程度与危险因素的相关性分析

以早产和年龄≤3个月、年龄≤3个月和潜在性疾病分别作为危险因素时，高危组SI中位数大于低危组，P均＜0.01，以早产和潜在性疾病为作为危险因素时亦有此趋势，可能由于高危组例数太少，差异未达显著界值（表1）。

上述3组危险因素的高危组SI≥3的百分比均高于低危组，高危组SI≥3相对危险度（RR）是低危组的2.80～4.70倍。早产和年龄≤3个月作为危险因素时, SI≥3者高危组13例（18.3%），低危组2例（3.9%），两组 RR差异有显著意义(P＜0.05)；其余两组危险因素时，高危组与低危组SI≥3者比，RR差异无显著意义 P略＞0.05（分别为0.07和0.08）。

潜在性疾病分别与其他两因素组合分析时，所有高危组和低危组SI≥3者差异无显著意义（P略＞0.