Anemia and anti-tuberculosis treatment outcome in persons with pulmonary tuberculosis: A multi-center prospective cohort study

Abstract

Background: Tuberculosis (TB) remains a major plague of humanity. People with TB (PWTB) are commonly anemic. Here, we assessed whether the severity of anemia in PWTB prior to anti-TB treatment (ATT) was a risk factor for an unfavorable outcome.

Methods: Patients ≥ 18 years old with culture-confirmed drug-susceptible pulmonary TB enrolled between 2015 and 2019 in a multi-center Brazilian cohort were followed for up to 24 months and classified according to anemia severity (mild, moderate, and severe), based on hemoglobin levels. A multinomial logistic regression model was employed to assess whether anemia was associated with unfavorable outcome (death, failure, loss to follow-up, regimen modification or relapse), compared to treatment success (cure or treatment completion).

Results: Among 786 participants who met inclusion criteria, 441 (56 %) were anemic at baseline. Patients with moderate/severe anemia were more HIV-seropositive, as well as more symptomatic and had higher frequencies of unfavorable outcomes compared to the other groups. Moderate/severe anemia (adjusted OR [aOR]: 7.80, 95 %CI:1.34-45.4, p = 0.022) was associated with death independent of sex, age, BMI, HIV and glycemic status.

Conclusion: Moderate/severe anemia prior to ATT was a significant risk factor for death. Such patients should be closely monitored given the high risk of unfavorable ATT outcomes.

Keywords: Anemia; Death; Hemoglobin; Tuberculosis; Tuberculosis treatment outcome.

Fig. 1.

Increased in anemia severity is associated with poor consumption habits, higher frequency of comorbidities, and of TB-related symptoms. (a) Among all the study participants (n = 786), 56 % had anemia: 42 % mild, 10 % moderate, and 4 % severe. (b) Frequency of consumption habits in patients stratified according to anemia severity. (c) BMI according to anemia severity. (d) Frequency of HIV according to anemia severity. (e) Frequency of TB clinical symptoms following the anemia severity. Groups were compared using the Pearson’s chi-square test or the Kruskall-Wallis test.

Fig. 2.

Anemia severity was associated with increased occurrence of unfavorable outcomes. (a) Frequency of unfavorable TB treatment outcomes according to anemia severity. (b) Frequency of each type of TB unfavorable outcome according to anemia severity. Groups were compared using the Pearson’s chi-square test.

Fig. 3.

Moderate and severe anemia are associated with increased mortality in patients with TB undergoing treatment. A multinomial logistic regression model (backward stepwise regression) was designed to test independent associations between clinical characteristics and the indicated TB treatment outcomes. Cure or treatment completed was considered as reference outcome. The variables included in the adjusted model were anemia severity, sex, age, BMI, HIV status and dysglycemia status.