Anemia of inflammation often resolved after TB treatment
Chemotherapy for tuberculosis resulted in significant reductions in anemia of inflammation, but had no effect on iron-deficiency anemia or multifactorial anemia, according to researchers from Cornell University.
“Anemia that had a sole or combination iron-responsive component made up almost half of all-cause anemia at TB diagnosis and remained mostly unresolved by the end of TB treatment,” the researchers wrote in Clinical Infectious Diseases. “Resolution of iron-responsive anemia calls for iron-focused interventions, and in the context of TB and malnutrition, this study demonstrates for the first time that the window of opportunity to intervene with iron appears to open as early as 2 months after TB treatment initiation.”
The researchers evaluated the cause of anemia among adult participants enrolled in the TB Case-Contact study in The Gambia: anemia of inflammation (AI), which is due to infection and does not respond to iron-based interventions; iron-deficiency anemia (IDA), which is due to iron supply problems and will respond to iron therapy; and multifactorial anemia (IDA+AI), which consists of both and poses a significant challenge, especially in sub-Saharan Africa.
The study included 45 patients with culture-confirmed pulmonary TB and 86 exposed contacts who were tested with tuberculin skin tests (TST) to determine their infection status: 47 were TST-positive, and 39 were TST-negative. The researchers measured baseline hemoglobin, ferritin, hepcidin, soluble transferrin receptor (sTfR) and transferrin in the cases and controls. The TB cases were followed for 2 and 6 months after TB treatment initiation.
Fifty-one patients (41%) in the entire cohort developed anemia of any cause, and AI was the cause of 45% of the cases. Among the 39 TB cases with anemia, 36% had AI. The proportion of patients with AI was greater in patients with TB compared with controls (P=.002), but there was no difference in the proportion of patients with IDA and IDA+AI. After 6 months of treatment, patients with TB had a significantly lower likelihood of all-cause anemia (adjusted OR=0.35; 95% CI, 0.14-0.86) and AI (aOR=0.19; 95% CI, 0.06-0.67) compared with TB diagnosis. TB treatment was not associated with resolution of iron-responsive anemia at diagnosis.
Concentrations of iron biomarkers also differed significantly. In patients with active, but untreated TB, the concentrations of ferritin, hepcidin and sTfR were higher compared with controls, and concentrations of transferrin and hemoglobin were lower. Ferritin, hepcidin and sTfR levels declined significantly 2 months after TB treatment, and were not statistically different from TST-negative contacts after 6 months of treatment.
“In light of this evidence, strategies to identify and treat anemia in TB should be re-evaluated to include classification of anemia and specific timing considerations that can be used to guide effective anemia intervention,” the researchers wrote.
Minchella PA. Clin Infect Dis. 2014;doi:10.1093/cid/ciu945
Source: Healio
