Tuberculosis-associated depression: a population-based cohort study of people immigrating to British Columbia, Canada, 1985–2015

• Published in: Annals of epidemiology Vol. 63; pp. 7 - 14
• Main Authors: Basham, C. Andrew, Karim, Mohammad Ehsanul, Cook, Victoria J., Patrick, David M., Johnston, James C.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-11-2021
• Subjects: British Columbia; Depression; Detection bias; Mediation analysis; Natural direct effect (NDE); Natural indirect effect (NIE); Tuberculosis; Tuberculosis; Natural indirect effect (NIE); Detection bias; Natural direct effect (NDE); Depression; British Columbia; Mediation analysis
• ISSN: 1047-2797; 1873-2585
• DOI: 10.1016/j.annepidem.2021.06.002

To estimate the risk of tuberculosis (TB)-associated depression. A second aim was to estimate the extent to which any increased risk of depression among TB patients may be mediated by the length of hospital length stay (LOS)
Retrospective cohort study of linked healthcare claims and public health surveillance data. Our primary outcome, time-to-depression, was analyzed using Cox proportional hazards (PH) regressions. Causal mediation analysis was used to estimate the natural direct and indirect effect of TB mediated by hospital LOS.
Among 755,836 participants (52.2% female, median age=35 years, median follow-up=8.75 years), 2295 were diagnosed with TB (exposure), and 128,963 were diagnosed with depression (outcome). We observed a covariate-adjusted hazard ratio (aHR) of 1.24 (95% CI, 1.14–1.34) for depression by TB. The total effect of TB on depression was decomposed into a natural direct effect of TB of aHR=1.11 (95% CI, 1.02–1.21) and an indirect effect through hospital LOS of aHR=1.11 (95% CI, 1.10–1.12), indicating that TB's total effect was mediated by 50% (95% CI, 35–82%) through hospital LOS.
TB patients had a 24% higher risk of developing depression. TB's effect was mediated substantially by hospital LOS, requiring further study. Depression screening among TB patients is warranted.