Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA.
Infect Control Hosp Epidemiol. 2010 Jan;31(1):78-84. doi: 10.1086/649022.
In patients with smear-positive pulmonary tuberculosis who are hospitalized or reside in congregate settings, guidelines recommend airborne infection isolation until sputum smear results are negative. Studies have identified factors associated with delayed sputum smear and culture conversion in patients with tuberculosis. Because these studies did not use methods of survival analysis, estimates of time to sputum smear conversion that are based on initial patient characteristics are not available. The ability to predict time to sputum smear conversion could be useful for programmatic planning and patient counseling.
We performed a cohort study using survival analysis to identify factors associated with time to sputum smear and culture conversion. We defined the time to sputum smear conversion as the time elapsed from the start of treatment to the first date of sustained conversion.
Ninety-eight patients had sputum smear samples positive for acid-fast bacilli. Lower initial smear grade (on 1+ to 4+ scale) and absence of cavitation on chest radiograph were associated with earlier sputum smear conversion in bivariate analysis. In multiple regression analysis, initial smear grade (hazard ratio, 0.45; 95% confidence interval, 0.35-0.57) and drug resistance (hazard ratio, 2.30; 95% confidence interval, 1.08-4.89) remained statistically significant; a model comprising only initial smear grade performed almost as well. Predictors of sputum culture conversion were similar.
Initial smear grade was the strongest predictor of time to sputum smear and culture conversion in patients with pulmonary tuberculosis and may be a useful predictor for programmatic planning and patient counseling.
在住院或居住在集体环境中的涂片阳性肺结核患者中，指南建议进行空气传播感染隔离，直至痰涂片结果转为阴性。研究已经确定了与肺结核患者痰涂片和培养转化延迟相关的因素。由于这些研究没有使用生存分析方法，因此基于初始患者特征的痰涂片转化时间估计值不可用。预测痰涂片转化时间的能力可能对规划和患者咨询有用。
我们进行了一项队列研究，使用生存分析来确定与痰涂片和培养转化时间相关的因素。我们将痰涂片转化时间定义为从开始治疗到首次持续转化的时间。
98 例患者的痰涂片样本抗酸杆菌阳性。初始涂片等级较低（1+至 4+）和胸部 X 线片无空洞与痰涂片转化较早有关。在多因素回归分析中，初始涂片等级（风险比，0.45；95%置信区间，0.35-0.57）和耐药性（风险比，2.30；95%置信区间，1.08-4.89）仍然具有统计学意义；仅包含初始涂片等级的模型表现几乎相同。痰培养转化的预测因素相似。
初始涂片等级是肺结核患者痰涂片和培养转化时间的最强预测因素，可能是规划和患者咨询的有用预测指标。
