Survival of people with untreated tuberculosis: effects of time, geography and setting

BackgroundAn estimated 40% of people who developed tuberculosis in 2021 were not diagnosed or treated. Pre-chemotherapy era data are a rich resource on survival for people with untreated TB. We aimed to identify heterogeneities in these data to inform more precise use of them. MethodsWe extracted survival data from pre-chemotherapy era papers reporting TB specific mortality and/or natural recovery data. We used Bayesian parametric survival analysis to model the survival distribution, stratifying by geography (North America versus Europe), time (pre-1930 versus post-1930), and setting (sanitoria versus non-sanitoria). ResultsWe found 12 studies with TB-specific mortality data. Ten-year survival was 69% in North America (95 CI: 54%-81%) and 36% in Europe (95% CI: 10%-71%). Only 38% (95% CI: 18%-63%) of non-sanitorium individuals survived to 10 years compared to 69% (95% CI: 41%-87%) of sanitoria/hospitalized patients. There were no significant differences between people diagnosed pre-1930 and post-1930 (five-year survival pre-1930: 65%; 95% CI: 44%-88% versus post-1930: 72%; 95% CI: 41%-94%). ConclusionsMortality and natural recovery risks vary substantially by location and setting. These heterogeneities need to be considered when using pre-chemotherapy data to make inferences about expected survival of people with undiagnosed TB.