COVID-19 pneumonia and the subsequent risk of getting active pulmonary tuberculosis: a population-based dynamic cohort study using national insurance claims databases.

Background: A three-fold increase in the incidence of detecting pulmonary tuberculosis (PTB) in patients hospitalised with COVID-19 pneumonia compared with that in the general population was recently reported; however, this finding may be due to admission bias in the diagnostic investigation. The current cohort study aimed to estimate the risk of having detectable active PTB after SARS-CoV-2 infection.

Methods: Insurance claims data in lower Southern Thailand from the 12th regional National Health Security Office, Thailand, were used. Inpatient and outpatient electronic medical records were linked using encrypted identification numbers. Records of individuals aged ≥18 years from 1 April to 30 September 2021 were retrieved to form a dynamic cohort. Exposure status was based on SARS-CoV-2 investigation and pneumonia status: population control (general population who had never been tested), negative reverse transcription-polymerase chain reaction (RT-PCR) control, asymptomatic COVID-19, symptomatic COVID-19 without pneumonia, and COVID-19 pneumonia groups. They were tracked in the databases for subsequent bacteriologically confirmed PTB until 31 March 2022.

Findings: Overall, 4,241,201 individuals were recruited in the dynamic cohort and contributed 3,108,224, 227,918, 34,251, 10,325, and 14,160 person-years in the above exposure groups, respectively. Time-varying Cox's regression was conducted using population control as reference. Hazard ratios (95% CIs) of the negative control, asymptomatic, symptomatic COVID-19 without pneumonia, and pneumonia groups were 1.58 (1.08, 2.32), 1.00 (0.25, 4.01), 2.98 (0.74, 11.98), 9.87 (5.64, 17.30) in the first 30 days and 0.97 (0.81, 1.15), 1.41 (0.92, 2.17), 3.85 (2.42, 6.13), and 7.15 (5.54, 9.22) thereafter, respectively.

Interpretation: Having had COVID-19 pneumonia, as opposed to the general population status, was strongly associated with a higher hazard of detectable active PTB. In tuberculosis endemic areas, patients with COVID-19 pneumonia should be closely followed up to reduce PTB-related burden.

Funding: The Fogarty International Center and the National Institute of Allergy and Infectious Diseases of the National Institutes of Health supported the article processing charges under Award Number D43TW009522.