Comparative Meta-Analysis of Tuberculosis Contact Investigation Interventions in Eleven High Burden Countries

Abstract

BackgroundScreening of household contacts of tuberculosis (TB) patients is a recommended strategy to improve early case detection. While it has been widely implemented in low prevalence countries, the most optimal protocols for contact investigation in high prevalence, low resource settings is yet to be determined. This study evaluated contact investigation interventions in eleven lower and middle income countries and reviewed the association between context or program-related factors and the yield of cases among contacts.MethodsWe reviewed data from nineteen first wave TB REACH funded projects piloting innovations to improve case detection. These nineteen had fulfilled the eligibility criteria: contact investigation implementation and complete data reporting. We performed a cross-sectional analysis of the percentage yield and case notifications for each project. Implementation strategies were delineated and the association between independent variables and yield was analyzed by fitting a random effects logistic regression.FindingsOverall, the nineteen interventions screened 139,052 household contacts, showing great heterogeneity in the percentage yield of microscopy confirmed cases (SS+), ranging from 0.1% to 6.2%). Compared to the most restrictive testing criteria (at least two weeks of cough) the aOR’s for lesser (any TB related symptom) and least (all contacts) restrictive testing criteria were 1.71 (95%CI 0.94−3.13) and 6.90 (95% CI 3.42−13.93) respectively. The aOR for inclusion of SS- and extra-pulmonary TB was 0.31 (95% CI 0.15−0.62) compared to restricting index cases to SS+ TB. Contact investigation contributed between <1% and 14% to all SS+ cases diagnosed in the intervention areas.ConclusionsThis study confirms that high numbers of active TB cases can be identified through contact investigation in a variety of contexts. However, design and program implementation factors appear to influence the yield of contact investigation and its concomitant contribution to TB case detection.

Drop-out from the tuberculosis contact investigation cascade in a routine public health setting in urban Uganda: A prospective, multi-center study

“…[19] Our findings are also consistent with previous work demonstrating that even members of vulnerable populations in Uganda have access to mobile phones. [20][21][22] Only 5% of index patients and 1% of contacts reported that they did not have access to a mobile phone, a functional precondition of household contact investigation in lowincome, urban settings where street addresses are uncommon.…”

Two methods for setting child-focused tuberculosis care targets

“…If neither is the case, then generalized risk estimates can be used. 3,9 Child contacts requiring evaluation The average number of children per household is estimated by dividing the number of children by the number of households. Multiplying the number of annually reported adult pulmonary TB cases by the average number of children per household estimates the number of child household contacts requiring evaluation in one year.…”

BUTIMBA: Intensifying the Hunt for Child TB in Swaziland through Household Contact Tracing

“…Meta-analysis of these recent initiatives demonstrated that program yield and contribution to case detection are dependent on program design and implementation [9]. Eligibility criteria used to guide evaluation of contacts demonstrated that compared to the most restrictive criteria (≥ 2 weeks of cough) the adjusted odds ratio for lesser (any TB related symptom) and the least (all contacts) restrictive testing criteria were 1.71 (95% CI 0.94–3.13) and 6.90 (95% CI 3.42–13.93), respectively [9]. Furthermore, contact investigation contributed to between <1% to 14% of all sputum smear positive cases in the intervention areas.…”