Comparative Yield of Tuberculosis during Active Case Finding Using GeneXpert or Smear Microscopy for Diagnostic Testing in Nepal: A Cross-Sectional Study.

Suman Chandra Gurung,Maxine Caws,Puskar Raj Paudel,Gokul Mishra,Jens W Levy,Andrew Ramsay,Mohammad Kashim Shah,Buddha Basnyat,Anil Thapa,Bhola Rai,Kritika Dixit,Deepak Malla,Bishal Subedi,Anil Shrestha,Raghu Dhital,Knut Lönnroth,Shraddha Acharya,Gangaram Budhathoki

doi:10.3390/tropicalmed6020050

Abstract

This study compared the yield of tuberculosis (TB) active case finding (ACF) interventions applied under TB REACH funding. Between June 2017 to November 2018, Birat Nepal Medical Trust identified presumptive cases using simple verbal screening from three interventions: door-to-door screening of social contacts of known index cases, TB camps in remote areas, and screening for hospital out-patient department (OPD) attendees. Symptomatic individuals were then tested using smear microscopy or GeneXpert MTB/RIF as first diagnostic test. Yield rates were compared for each intervention and diagnostic method. We evaluated additional cases notified from ACF interventions by comparing case notifications of the intervention and control districts using standard TB REACH methodology. The project identified 1092 TB cases. The highest yield was obtained from OPD screening at hospitals (n = 566/1092; 52%). The proportion of positive tests using GeneXpert (5.5%, n = 859/15,637) was significantly higher than from microscopy testing 2% (n = 120/6309). (OR = 1.4; 95%CI = 1.12–1.72; p = 0.0026). The project achieved 29% additionality in case notifications in the intervention districts demonstrating that GeneXpert achieved substantially higher case-finding yields. Therefore, to increase national case notification for TB, Nepal should integrate OPD screening using GeneXpert testing in every district hospital and scale up of community-based ACF of TB patient contacts nationally.

Highlights

Tuberculosis (TB) is an ancient disease which remains one of the most intractable public health challenges
Case finding was implemented by Birat Nepal medical trust (BNMT) in eight districts from June 2017 to November 2018 supported by TB REACH wave 5 funding
Standard operating procedures for the smear microscopy and GeneXpert testing followed the standard Nepal National TB Programme (NTP) guidelines, which are based on the relevant WHO protocols and the manufacturer’s standard operating procedures [11,12]

Summary

Introduction

Tuberculosis (TB) is an ancient disease which remains one of the most intractable public health challenges. In 2019, approximately 10 million people developed TB, and 1.5 million died from this preventable, curable disease [1]. In 2019, over three million cases remained missing from government National TB Programme (NTP) notifications [1]. To accelerate progress towards the END-TB strategy target of reducing TB incidence by 90% by 2035, WHO has strongly recommended high-incidence countries scale up active case finding (ACF) and systematic screening in specific risk populations such as close contacts of index patients [2,3]. Integrating ACF into existing healthcare services is important to optimize resources and achieve sustainability [4]

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