A mini systematic review of prognostic factors in elderly patients with tuberculosis

Background While advanced age has been suggested as a prognostic factor in patients with tuberculosis, the characteristics associated with a poor outcome in elderly patients have remained unclear. The aim of this systematic review was to describe the risk factors for a poor outcome in elderly patients with tuberculosis. Methods We identified 1255 studies published between 1919 and 2017 from the PubMed database by using combinations of the keywords "tuberculosis [Title/Abstract]" and "elderly [Title/Abstract]". Full texts of the studies that met the inclusion criteria were further evaluated by two independent investigators. Results even retrospective cohort studies were included in this systematic review. More advanced age, comorbidities, and nutritional status were likely to be prognostic factors in Taiwan (aging country) and Japan (super-aged country), while human immunodeficiency virus infection and severe tuberculosis were associated with a poor outcome in low-income countries. Two studies from Taiwan investigated the prognostic factors of tuberculosis-specific death and non-tuberculosis-specific death separately, but no significant differences were found in the factors between the two types of death. Conclusions The prognostic factors of tuberculosis in elderly patients varied according to the income levels of the countries. The factors in Taiwan and Japan were mainly associated with host factors, irrespective of the cause of death, which may reflect senile deterioration due to old age.