Impact of isoniazid preventive therapy on mortality among children less than 5 years old following exposure to tuberculosis at home in Guinea-Bissau: a prospective cohort study.

OBJECTIVE: In a cohort of children less than 5 years old exposed to adult intrathoracic tuberculosis (TB) in 1996-1998, we found 66% increased mortality compared with community controls. In 2005, we implemented isoniazid preventive therapy (IPT) for children exposed to TB at home, and the present study evaluates the effect of this intervention on mortality. SETTING: This prospective cohort study was conducted in six suburban areas included in the demographic surveillance system of the Bandim Health Project in Bissau, the capital city of Guinea-Bissau. PARTICIPANTS: All children less than 5 years of age and living in the same house as an adult with intrathoracic TB registered for treatment in the study area between 2005 and 2007 were evaluated for inclusion in the IPT programme. MAIN OUTCOME MEASURES (END POINTS): The all-cause mortality rate ratio (MRR) between exposed children on IPT, exposed without IPT and unexposed community control children. RESULTS: A total of 1396 children were identified as living in the same houses as 416 adult TB cases; of those, 691 were enrolled in the IPT programme. Compared with community controls, the IPT children had an MRR of 0.30 (95%CI 0.1 to 1.2). The MRR comparing exposed children with and without IPT was 0.21 (0.0 to 1.1). The relative mortality in IPT children compared with community controls in 2005-2008 differed significantly from the relative mortality of exposed untreated children compared with the community controls in 1996-1998 (test of interaction, p=0.01). CONCLUSIONS: In 2005-2008, exposed children on IPT had 70% lower mortality than the community control children, though not significantly. Relative to the community control children, the mortality among TB-exposed children on IPT in 2005-2008 was significantly lower than the mortality among TB-exposed children not on IPT in 1996-1998.

Impact of tuberculosis exposure at home on mortality in children under 5 years of age in Guinea-Bissau.

OBJECTIVE: To assess mortality related to exposure to tuberculosis (TB) at home among children in urban areas of Guinea-Bissau. METHODS: In four suburban areas included in the demographic surveillance system of the Bandim Health Project in Bissau, the mortality of children aged <5 years living with an adult with TB was compared with the mortality of children in the general population. RESULTS: Children <5 years of age exposed to an adult with intrathoracic TB had 66% higher mortality than unexposed children (HR 1.66, 95% CI 1.2 to 2.3). The risk was higher for children living in the same family as a TB case (HR 2.15, 95% CI 1.3 to 3.7) than for children living in the same house but not belonging to the same family as the TB case (HR 1.51, 95% CI 1.0 to 2.2). For children whose mother had TB, mortality was increased eightfold (HR 7.82, 95% CI 2.1 to 30). The risk of death was particularly increased from 6 months following exposure (HR 2.16, 95% CI 1.5 to 3.2) and the highest rate of excess mortality was found in children aged 3­4 years. Excess mortality was highest among children with close contact with an adult with sputum-positive pulmonary TB (HR 1.90, 95% CI 1.1 to 3.2), but contact with a sputum-negative case was also associated with increased mortality (HR 1.55, 95% CI 1.0 to 2.3). Adjusting for potential confounding factors did not change these results. The mortality among children living in the same houses 3 years earlier was not increased (HR 0.90, 95% CI 0.6 to 1.3). CONCLUSION: Intimate family contact with a TB case represents a significant risk factor for child mortality in a low-income country.