Do community-based active case-finding interventions have indirect impacts on wider TB case detection and determinants of subsequent TB testing behaviour? A systematic review

Abstract

Community-based active case-finding (ACF) may have important impacts on routine TB case-detection and subsequent patient-initiated diagnosis pathways, contributing “indirectly” to infectious diseases prevention and care. We investigated the impact of ACF beyond directly diagnosed patients for TB, using routine case-notification rate (CNR) ratios as a measure of indirect effect. We systematically searched for publications 01-Jan-1980 to 13-Apr-2020 reporting on community-based ACF interventions compared to a comparison group, together with review of linked manuscripts reporting knowledge, attitudes, and practices (KAP) outcomes or qualitative data on TB testing behaviour. We calculated CNR ratios of routine case-notifications (i.e. excluding cases identified directly through ACF) and compared proxy behavioural outcomes for both ACF and comparator communities. Full text manuscripts from 988 of 23,883 abstracts were screened for inclusion; 36 were eligible. Of these, 12 reported routine notification rates separately from ACF intervention-attributed rates, and one reported any proxy behavioural outcomes. Two further studies were identified from screening 1121 abstracts for linked KAP/qualitative manuscripts. 8/12 case-notification studies were considered at critical or serious risk of bias. 8/11 non-randomised studies reported bacteriologically-confirmed CNR ratios between 0.47 (95% CI:0.41–0.53) and 0.96 (95% CI:0.94–0.97), with 7/11 reporting all-form CNR ratios between 0.96 (95% CI:0.88–1.05) and 1.09 (95% CI:1.02–1.16). One high-quality randomised-controlled trial reported a ratio of 1.14 (95% CI 0.91–1.43). KAP/qualitative manuscripts provided insufficient evidence to establish the impact of ACF on subsequent TB testing behaviour. ACF interventions with routine CNR ratios >1 suggest an indirect effect on wider TB case-detection, potentially due to impact on subsequent TB testing behaviour through follow-up after a negative ACF test or increased TB knowledge. However, data on this type of impact are rarely collected. Evaluation of routine case-notification, testing and proxy behavioural outcomes in intervention and comparator communities should be included as standard methodology in future ACF campaign study designs.

Decline in prevalence of tuberculosis following an intensive case-finding campaign and the COVID-19 pandemic in an urban Ugandan community

“…Besides directly detecting TB, our case-finding campaigns also contained a strong community mobilisation component, and we observed sustained rates of care-seeking and TB diagnosis during all but the most restrictive period of pandemic lockdowns. As observed in other case-finding studies [20], increased TB awareness resulting from the study may have encouraged people to seek care for TB symptoms even if not directly screened, or increased clinicians’ index of suspicion for TB. In addition, the regular presence of research staff at local health facilities, and their inquiries about patients who had tested positive for TB and not yet started treatment, may have improved treatment initiation for patients diagnosed with TB through routine care.…”

Delay in seeking treatment and associated factors among pulmonary tuberculosis patients attending public health facilities in the Metekel zone, Benishangul Gumuz region, Western Ethiopia

“…Establishing collaborative efforts with community leaders can facilitate the dissemination of accurate information about TB, dispelling myths, and encouraging individuals to seek formal medical care promptly ( 48 ). The introduction of community screening programs is another key strategy to address delays in seeking treatment ( 49 ). By bringing TB testing and treatment closer to communities, these programs can overcome barriers related to geographical distance and contribute to early case detection.…”

Impact of active case-finding for tuberculosis on case-notifications in Blantyre, Malawi: A community-based cluster-randomised trial (SCALE)

“…We found no significant impact of the ACF intervention or community TB prevalence survey (which is also a form of ACF, since it aimed to identify undiagnosed TB) on TB case-notifications, although our study had insufficient power to fully assess whether the observed 12% increase in bacteriologically-confirmed case notifications was significant or not. Our analysis of time trends suggests that there may have been a small peak in TB case notification rate after the intervention/prevalence survey in both arms followed by a dip, as would be expected with the substitution effect, whereby patients who would otherwise have been diagnosed routinely during the intervention period and immediately afterwards are instead found though ACF [ 12 ]. This substitution effect could account for the observed non-significant 12% increase in bacteriologically-confirmed case notifications and non-significant decreased case notifications for all registrations and all form TB.…”

“…Less intensive, enhanced case-finding (ECF) uses health information or awareness campaigns to encourage health-seeking behaviour when people experience TB symptoms, with or without access to diagnostics at community-level [ 10 ]. Evidence of an indirect effect, for example health promotion, may be reflected in prolonged increased TB notifications due to a change in testing behaviour through increased knowledge of symptoms and diagnosis, reducing TB stigma, changing social norms, or providing a prompt for symptomatic people to attend a health facility for testing [ 12 ]. Because of the high cost, and risk of false-positive and false-negative screening results, community-wide ACF is conditionally recommended only for general populations with undiagnosed TB of 500 per 100,000 population or higher [ 10 , 13 ].…”

“…Sustainable Community Active-case finding for Lung Health (SCALE) was a cluster-randomised trial investigating the impact of ACF on cluster-level TB case-notification rates in Blantyre city, Malawi, with 2013–14 estimates of 1,014 per 100,000 adults with undiagnosed infectious TB [ 16 ]. We also investigated facility-based TB case-notifications following ACF in each cluster given potential to indirectly affect subsequent TB testing rates by health promotion [ 12 ].…”