Association between diagnostic delay and prognosis of pulmonary tuberculosis in Shandong, China: a retrospective study

BACKGROUND: Tuberculosis (TB) is one of the main infectious diseases that seriously threatens global health, while diagnostic delay (DD) and treatment dramatically threaten TB control. METHODS: Between 2005 and 2017 in Shandong, China, we enrolled pulmonary tuberculosis (PTB) patients with DD. DD trends were evaluated by Joinpoint regression, and associations between PTB patient characteristics and DD were estimated by univariate and multivariate logistic regression. The influence of DD duration on prognosis and sputum smear results were assessed by Spearman correlation coefficients. RESULTS: We identified 208,822 PTB cases with a median DD of 33 days (interquartile range (IQR) 18–63). The trend of PTB with DD declined significantly between 2009 and 2017 (annual percent change (APC): − 4.0%, P = 0.047, 2009–2013; APC: − 6.6%, P = 0.001, 2013–2017). Patients aged > 45 years old (adjusted odds ratio (aOR): 1.223, 95% confidence interval (CI) 1.189–1.257, 46–65 years; aOR: 1.306, 95% CI 1.267–1.346, > 65 years), farmers (aOR: 1.520, 95% CI 1.447–1.596), and those with a previous treatment history (aOR: 1.759, 95% CI 1.699–1.821) were prone to developing long DD (> 30 days, P < 0.05). An unfavorable outcome was negatively associated with a short DD (OR: 0.876, 95% CI 0.843–0.910, P < 0.001). Sputum smear positive rate and unfavorable outcomes were positively correlated with DD duration (Spearman correlation coefficients (rs) = 1, P < 0.001). CONCLUSIONS: The DD situation remains serious; more efficient and comprehensive strategies are urgently required to minimize DD, especially for high-risk patients.