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间是一种无需实验室检测的生物标志物，可应用于资源匮乏环境，且与疾病传播及治疗应答密切相关。与咳嗽频率升高相关的影像学特征，或对阐明疾病传播机制具有重要意义。目前尚无关于咳嗽频率与空洞性肺部疾病之间关联的研究。
方法：本研究纳入41例人类免疫缺陷病毒（Human Immunodeficiency Virus, HIV）阴性的成人受试者，均为全程接受治疗的培养确认药物敏感性肺结核患者。咳嗽录音采用卡耶塔诺咳嗽监测仪（Cayetano Cough Monitor）完成；痰液样本采用显微镜观察药敏肉汤培养法进行检测，对于培养阳性样本，则通过阳性出现时间评估菌负荷。由一名美国医学委员会认证的放射科医师及一款自动化计算机算法分别对计算机断层扫描（Computed Tomography, CT）影像进行分析，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。本研究对比了小空洞（≤7mL）与大空洞（>7mL）、位置更靠近气道（≤10mm）与远离气道（>10mm）的患者，直至治疗第62天的咳嗽频率及咳嗽停止情况。
结果：治疗期间，存在大体积空洞（率比[Rate Ratio, RR]=1.98，P=0.01）以及空洞位置更靠近气道（RR=2.44，P=0.001）的受试者，其咳嗽频率较对照组升高2倍。与之类似，存在小空洞（校正风险比[adjusted Hazard Ratio, HR]=2.89，P=0.06）以及空洞远离气道者（校正HR=3.61，P=0.02）的咳嗽停止速度快3倍。治疗期间的菌负荷及培养转阴结果也呈现相似趋势。
结论：治疗期间，存在较大空洞的患者（尤其是空洞位置更靠近气道者），其咳嗽频率更高、咳嗽持续时间更久。