目的 探讨百日咳患儿合并肺炎及重症肺炎的临床特征及危险因素，为临床早期干预与分层管理提供依据。方法 回顾性分析2021年8月至2024年6月我院收治的708例百日咳住院患儿的临床资料。根据病情严重程度将患儿分为未合并肺炎组（306例）、普通肺炎组（316例）和重症肺炎组（86例）。比较各组入院时的临床特征和实验室指标等，以未合并肺炎组为参照，采用多元logistic回归模型分析百日咳患儿发生普通肺炎及重症肺炎的独立相关因素。结果 708例患儿中，男性400例（56.5%），女性308例（43.5%），中位年龄4月龄（1~4岁），≤3月龄婴儿占46.3%。混合感染率为68.50%（485/708），以鼻病毒最常见。重症肺炎组在月龄≤3月、未接种百白破疫苗（DTP）、合并基础疾病、发热、白细胞计数（WBC）、低百日咳杆菌循环阈值（BP-C_t）值等指标上与其他两组差异有统计学意义（均P<0.05），而普通肺炎组与未合并肺炎组上述指标无显著差异（均P>0.05）。多元logistic回归分析显示，普通肺炎组与未合并肺炎组相比，各基线指标均无统计学差异（P>0.05）。对于重症肺炎，发热（OR=10.601，95%CI：5.235~21.466）、合并基础疾病（OR=5.576，95%CI：2.651~11.726）、低BP-C_t值（高菌量）（OR=5.174，95%CI：1.911~14.005）和WBC>30×10⁹/L（OR=3.371，95%CI：1.520-7.474）是百日咳患儿进展为重症肺炎独立危险因素。结论 肺炎是百日咳住院患儿常见的并发症。普通肺炎与单纯百日咳在入院早期临床特征上难以区分；而发热、合并基础疾病、高百日咳菌量（低BP-C_t值）及高白细胞计数是百日咳患儿进展为重症肺炎的早期预警指标。临床上可早期监测干预以改善患儿预后。

Objective To analyze the clinical characteristics of pertussis in children and explore the independent risk factors for pertussis complicated by ordinary pneumonia and severe pneumonia. Methods A retrospective cohort study was conducted on the clinical data of 708 children hospitalized with pertussis in our hospital from August 2021 to June 2024. Patients were divided into three groups: pertussis without pneumonia (n=306), pertussis with ordinary pneumonia (n=316), and pertussis with severe pneumonia (n=86). Baseline clinical characteristics and laboratory indicators upon admission were compared. Multinomial logistic regression analysis (with the non-pneumonia group as the reference) was used to identify independent factors associated with ordinary and severe pneumonia. Results Among the 708 children, 400 were male (56.5%) and 308 were female (43.5%), with a median age of 4 months (1 month - 4 years), infants≤3 months accounted for 46.3%. The co-infection rate was 68.50%, with rhinovirus being the most common. Significant differences were found among the three groups in age, fever, underlying diseases, DTP vaccination status, WBC count, LYM% and Bordetella pertussis cycle threshold (BP-C_t) values (P<0.05). Post-hoc comparisons showed significant differences in these indicators for the severe pneumonia group compared to the other two groups, whereas no significant differences were observed between the ordinary pneumonia and non-pneumonia groups. Multinomial logistic regression analysis showed no statistically significant independent predictors for distinguishing ordinary pneumonia from non-pneumonia (P>0.05). However, for severe pneumonia, fever (OR=10.601, 95%CI: 5.235-21.466), underlying diseases (OR=5.576, 95%CI: 2.651-11.726), low BP-C_t value (high bacterial load) (OR=5.174, 95%CI: 1.911-14.005), and WBC>30×10⁹/L (OR=3.371, 95%CI: 1.520-7.474) were identified as independent risk factors. Conclusion Pneumonia is a common complication in hospitalized children with pertussis. While ordinary pneumonia is clinically difficult to distinguish from uncomplicated pertussis in the early stages, fever, underlying diseases, high bacterial load (low BP-C_t), and hyperleukocytosis serve as early warning indicators for the progression to severe pneumonia.