The epidemiological characteristics and infection risk factors for extrapulmonary tuberculosis in patients hospitalized with pulmonary tuberculosis infection in China from 2017 to 2021

BACKGROUND: Pulmonary tuberculosis (PTB) complicated with extrapulmonary tuberculosis (EPTB) infection can aggravate the disease, but there have been few reports. METHODS: Retrospective analysis was used to collect the clinical data of PTB patients with pathogen positive in a teaching hospital from 2017 to 2021. We describe the incidence, the invasive site of EPTB patients, and analyze the infection risk factors for PTB with EPTB by univariate and multivariate logistic regression models. We also compared the complications, disease burden with chi-square test and rank-sum test. RESULTS: A total of 1806 PTB were included, of which 263 (14.6%) were complicated with EPTB. The common invasive sites for EPTB were neck lymph nodes (16.49%), intestines (16.13%), and meninges (10.75%). Age ≤ 40 (OR = 1.735; 95%CI [1.267–2.376]; P = 0.001), malnutrition (OR = 2.029; 95%CI [1.097–3.753]; P = 0.022), anemia (OR = 1.739; 95%CI[1.127–2.683]; P = 0.012), and osteoporosis (OR = 4.147; 95%CI [1.577–10.905]; P = 0.004) were all independent risk factors for PTB infection with EPTB. The incidence of extrathoracic hydrothorax, intestinal bacterial infection, urinary tract bacterial infection, and abdominal bacterial infection were higher in patients with PTB with EPTB. PTB with EPTB patients also had longer median hospitalization durations (19 vs. 14 days), during which time they incurred higher total costs, laboratory test costs, imaging examination costs, and drug use costs. CONCLUSION: This study found important risk factors for PTB complicated with EPTB, such as age ≤ 40, malnutrition, anemia, and osteoporosis. PTB with EPTB patients have more extrapulmonary complications and higher hospitalization disease burden.