Data from: Cough frequency during treatment associated with baseline cavitary volume and proximity to the airway in pulmonary tuberculosis

Background: Cough frequency, and its duration, is a lab-free biomarker that can be used in low-resource settings and has been associated with transmission and treatment response. Radiological characteristics associated with increased cough frequency may be important in understanding transmission. The relationship between cough frequency and cavitary lung disease has never been studied. Methods: We analyzed 41 human immunodeficiency virus-negative adults with culture-confirmed, drug-susceptible pulmonary tuberculosis throughout treatment. Cough recordings were based on the Cayetano Cough Monitor and sputum samples were evaluated using microscopic-observation drug susceptibility broth culture, among culture-positive samples bacillary burden was assessed by time to positivity. Computerized tomography scans were analyzed by a U.S. board-certified radiologist and an automated-computer algorithm. The algorithm evaluates cavity volume and cavitary proximity to the airway. Computerized tomography scans were taken within one month of treatment initiation. We compared small cavities (≤7-mL) versus large cavities (>7-mL) and cavities located closer to (≤10-mm) and farther (>10-mm) from the airway to cough frequency and cough cessation until treatment day 62. Results: Cough frequency during treatment was two-fold higher in participants with large cavity volumes (Rate Ratio [RR]=1.98, p=0.01) and cavities located closer to the airway (RR=2.44, p=0.001). Comparably, cough ceased three times faster in smaller cavities (adjusted hazard ratio [HR]=2.89, p=0.06) and those farther from the airway (adjusted HR=3.61, p=0.02). Similar results are found for bacillary burden and culture conversion during treatment. Conclusions: Cough frequency during treatment is greater and lasts for longer in patients with larger cavities, especially those closer to the airway.

背景：咳嗽频率及其持续时长是一种无需实验室检测的生物标志物，可应用于资源匮乏地区，且与疾病传播及治疗反应相关。与咳嗽频率升高相关的放射学特征，对阐明疾病传播机制具有重要参考价值。目前尚无关于咳嗽频率与空洞性肺部疾病（cavitary lung disease）之间关联的研究。
方法：本研究纳入41例人类免疫缺陷病毒（human immunodeficiency virus, HIV）阴性、经培养证实的药物敏感性肺结核成人受试者，全程随访其治疗过程。咳嗽录音采用卡耶塔诺咳嗽监测仪（Cayetano Cough Monitor）完成；痰标本采用显微镜观察药敏肉汤培养法进行检测，对于培养阳性的标本，通过阳性检出时间评估细菌负荷。计算机断层扫描（Computed Tomography, CT）图像由美国委员会认证放射科医师及自动化计算机算法分别分析，该算法可评估空洞体积及空洞与气道的距离。所有CT扫描均在治疗启动后1个月内完成。本研究将受试者分为小空洞（≤7mL）组与大空洞（>7mL）组，以及与气道距离较近（≤10mm）组与较远（>10mm）组，比较不同分组的咳嗽频率及治疗第62天时的咳嗽停止情况。
结果：治疗期间，合并大空洞的受试者咳嗽频率较对照组升高1倍（风险比[Rate Ratio, RR]=1.98，P=0.01），合并与气道距离较近的空洞者咳嗽频率同样显著升高（RR=2.44，P=0.001）。与之相对，合并小空洞的受试者咳嗽停止时间较对照组快3倍（校正后风险比[adjusted hazard ratio, HR]=2.89，P=0.06），合并与气道距离较远的空洞者咳嗽停止速度更快（校正后HR=3.61，P=0.02）。治疗期间的细菌负荷及培养转阴情况也得到了相似的结果。
结论：治疗期间，合并大空洞的患者咳嗽频率更高、咳嗽持续时间更长，尤其是空洞与气道距离较近的患者。