The Importance of Implementation Strategy in Scaling Up Xpert MTB/RIF for Diagnosis of Tuberculosis in the Indian Health-Care System: A Transmission Model

Background:india has announced a goal of universal access to quality tuberculosis (tb) diagnosis and treatment. a number of novel diagnostics could help meet this important goal. the rollout of one such diagnostic,xpert mtb/rif (xpert) is being considered,but if xpert is used mainly for people with hiv or high risk of multidrug-resistant tb (mdr-tb) in the public sector,population-level impact may be limited.methods and findings:we developed a model of tb transmission,care-seeking behavior,and diagnostic/treatment practices in india and explored the impact of six different rollout strategies. providing xpert to 40% of public-sector patients with hiv or prior tb treatment (similar to current national strategy) reduced tb incidence by 0.2% (95% uncertainty range [ur]: -1.4%,1.7%) and mdr-tb incidence by 2.4% (95% ur: -5.2%,9.1%) relative to existing practice but required 2,500 additional mdr-tb treatments and 60 four-module genexpert systems at maximum capacity. further including 20% of unselected symptomatic individuals in the public sector required 700 systems and reduced incidence by 2.1% (95% ur: 0.5%,3.9%); a similar approach involving qualified private providers (providers who have received at least some training in allopathic or non-allopathic medicine) reduced incidence by 6.0% (95% ur: 3.9%,7.9%) with similar resource outlay,but only if high treatment success was assured. engaging 20% of all private-sector providers (qualified and informal [providers with no formal medical training]) had the greatest impact (14.1% reduction,95% ur: 10.6%,16.9%),but required >2,200 systems and reliable treatment referral. improving referrals from informal providers for smear-based diagnosis in the public sector (without xpert rollout) had substantially greater impact (6.3% reduction) than xpert scale-up within the public sector. these findings are subject to substantial uncertainty regarding private-sector treatment patterns,patient care-seeking behavior,symptoms,and infectiousness over time; these uncertainties should be addressed by future research.conclusions:the impact of new diagnostics for tb control in india depends on implementation within the complex,fragmented health-care system. transformative strategies will require private/informal-sector engagement,adequate referral systems,improved treatment quality,and substantial resources.please see later in the article for the editors' summary. © 2014 salje et al.