Increased Case Notification through Active Case Finding of Tuberculosis among Household and Neighbourhood Contacts in Cambodia

Abstract

BackgroundGlobally, there has been growing evidence that suggests the effectiveness of active case finding (ACF) for tuberculosis (TB) in high-risk populations. However, the evidence is still insufficient as to whether ACF increases case notification beyond what is reported in the routine passive case finding (PCF). In Cambodia, National TB Control Programme has conducted nationwide ACF with Xpert MTB/RIF that retrospectively targeted household and neighbourhood contacts alongside routine PCF. This study aims to investigate the impact of ACF on case notifications during and after the intervention period.MethodsUsing a quasi-experimental cluster randomized design with intervention and control arms, we compared TB case notification during the one-year intervention period with historical baseline cases and trend-adjusted expected cases, and estimated additional cases notified during the intervention period (separately for Year 1 and Year 2 implementation). The proportion of change in case notification was compared between intervention and control districts for Year 1. The quarterly case notification data from all intervention districts were consolidated, aligning different implementation quarters, and separately analysed to explore the additionality. The effect of the intervention on the subsequent case notification during the post-intervention period was also assessed.ResultsIn Year 1, as compared to expected cases, 1467 cases of all forms (18.5%) and 330 bacteriologically-confirmed cases (9.6%) were additionally notified in intervention districts, whereas case notification in control districts decreased by 2.4% and 2.3%, respectively. In Year 2, 2737 cases of all forms (44.3%) and 793 bacteriologically-confirmed cases (38%) were additionally notified as compared to expected cases. The proportions of increase in case notifications from baseline cases and expected cases to intervention period cases were consistently higher in intervention group than in control group. The consolidated quarterly data showed sharp rises in all forms and bacteriologically-confirmed cases notified during the intervention quarter, with 64.6% and 68.4% increases (compared to baseline cases), and 46% and 52.9% increases (compared to expected cases), respectively. A cumulative reduction of case notification for five quarters after ACF reached more than -200% of additional cases.ConclusionsThe Cambodia’s ACF with Xpert MTB/RIF that retrospectively targeted household and neighbourhood contacts resulted in the substantial increase in case notification during the intervention period and reduced subsequent case notification during the post-intervention period. The applicability of retrospective contact investigation in other high-burden settings should be explored.

Effectiveness of Contact Tracing of Index Tuberculosis Cases in Nigeria

“…According to the study the pre and post intervention results were statistically significant which implies that educating of health workers on contact tracing will improve skills and case notification. Similarly a retrospective quasi-experimental cluster randomized design study among household and neighborhood contacts was conducted by [70] to ascertain the effectiveness of contact tracing to TB case-finding. The study is a qualitative study with intervention and control group using Xpert/MTB-RIF assay.…”

“…The findings revealed a significant increase in number of cases detected in the intervention areas when compared to control areas, this underpins the significant of contact tracing process in TB case detection. [70] conducted a study on the impact of contact tracing of TB case detection and opined that contact tracing is a DOI: 10.4236/aid.2018.84016 comprehensive and strategic method of finding missing cases of TB.…”

“…Furthermore, [70] conducted a prospective study on contact tracking of pediatric index cases using qualitative and quantitative methodology. The respondents were selected based on standard definitions of terms.…”

Community health volunteers’ contribution to Tuberculosis patients notified to National Tuberculosis program in Kenya

“…Studies conducted in high burden areas have shown that active case finding among household contacts yields substantially more TB cases than passive case detection. (2,4,5) Kenya is among the 30 high TB burden countries in the world and is among the top 5 from sub Saharan Africa. Tuberculosis is the fourth biggest killer in Kenya after HIV/AIDS, maternal deaths and lower respiratory infections (1).…”

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

“…Specifically, there are few details about when and where participants are lost-to-follow-up, essential information for designing interventions to improve delivery of contact investigation. [3][4][5] Cascade analysis, frequently applied to understand cumulative losses along the HIV care continuum [6,7], can clarify the most important gaps in delivery of TB evaluation and care, and in so doing inform the design and targeting of interventions. [8] Identifying TB patients via household contact investigation depends on effectively completing four key steps in the delivery cascade: 1) scheduling visits to homes of index TB patients; 2) initiating these visits by physically reaching the homes of index patients; 3) screening all household contacts; and 4) ensuring that all symptomatic and high-risk contacts complete TB evaluation.…”