The Tuberculosis Cascade of Care in India's Public Sector: A Systematic Review and Meta-analysis

Abstract

Background: India has 23% of the global burden of active tuberculosis (TB) patients and 27% of the world's "missing" patients, which includes those who may not have received effective TB care and could potentially spread TB to others. The "cascade of care" is a useful model for visualizing deficiencies in case detection and retention in care, in order to prioritize interventions.

Methods and findings: The care cascade constructed in this paper focuses on the Revised National TB Control Programme (RNTCP), which treats about half of India's TB patients. We define the TB cascade as including the following patient populations: total prevalent active TB patients in India, TB patients who reach and undergo evaluation at RNTCP diagnostic facilities, patients successfully diagnosed with TB, patients who start treatment, patients retained to treatment completion, and patients who achieve 1-y recurrence-free survival. We estimate each step of the cascade for 2013 using data from two World Health Organization (WHO) reports (2014-2015), one WHO dataset (2015), and three RNTCP reports (2014-2016). In addition, we conduct three targeted systematic reviews of the scientific literature to identify 39 unique articles published from 2000-2015 that provide additional data on five indicators that help estimate different steps of the TB cascade. We construct separate care cascades for the overall population of patients with active TB and for patients with specific forms of TB-including new smear-positive, new smear-negative, retreatment smear-positive, and multidrug-resistant (MDR) TB. The WHO estimated that there were 2,700,000 (95%CI: 1,800,000-3,800,000) prevalent TB patients in India in 2013. Of these patients, we estimate that 1,938,027 (72%) TB patients were evaluated at RNTCP facilities; 1,629,906 (60%) were successfully diagnosed; 1,417,838 (53%) got registered for treatment; 1,221,764 (45%) completed treatment; and 1,049,237 (95%CI: 1,008,775-1,083,243), or 39%, of 2,700,000 TB patients achieved the optimal outcome of 1-y recurrence-free survival. The separate cascades for different forms of TB highlight different patterns of patient attrition. Pretreatment loss to follow-up of diagnosed patients and post-treatment TB recurrence were major points of attrition in the new smear-positive TB cascade. In the new smear-negative and MDR TB cascades, a substantial proportion of patients who were evaluated at RNTCP diagnostic facilities were not successfully diagnosed. Retreatment smear-positive and MDR TB patients had poorer treatment outcomes than the general TB population. Limitations of our analysis include the lack of available data on the cascade of care in the private sector and substantial uncertainty regarding the 1-y period prevalence of TB in India.

Conclusions: Increasing case detection is critical to improving outcomes in India's TB cascade of care, especially for smear-negative and MDR TB patients. For new smear-positive patients, pretreatment loss to follow-up and post-treatment TB recurrence are considerable points of attrition that may contribute to ongoing TB transmission. Future multisite studies providing more accurate information on key steps in the public sector TB cascade and extension of this analysis to private sector patients may help to better target interventions and resources for TB control in India.

Fig 1. A model for the tuberculosis cascade of care in India that integrates the WHO onion model with concepts from the HIV cascade of care.

Adapted from WHO, 2009 [11].

Fig 2. Forest plot of studies estimating the proportion of individuals in the community with cough >2 wk who report not having visited any medical provider after the onset of cough (Gap 1b).

ES, effect size; CI, confidence interval.

Fig 3. Forest plot of studies estimating the proportion of individuals in the community with cough >2 wk who report not having visited a public sector provider after the onset of cough (Gap 1b).

ES, effect size; CI, confidence interval.

Fig 4. Forest plot of studies estimating the proportion of individuals in the community with cough >2 wk who report not having visited a private sector provider after the onset of cough (Gap 1b).

ES, effect size; CI, confidence interval.

Fig 5. Forest plot of studies estimating the proportion of patients who fail to provide a second sputum smear (i.e., “diagnostic default”), which allows estimation of the proportion of smear-positive TB patients who might be “missed” at TB diagnostic facilities (Gap 2).

ES, effect size; CI, confidence interval.

Fig 6. Forest plot of studies estimating pretreatment loss to follow-up (i.e., “initial default”) of smear-positive TB patients in India (Gap 3).

ES, effect size; CI, confidence interval.

Fig 7. The cascade of care for all forms of tuberculosis in India’s Revised National Tuberculosis Control Programme (RNTCP) in India, 2013.

Error bars depict 95% confidence intervals.

Fig 8. The tuberculosis cascade of care for new smear-positive tuberculosis patients detected and treated by the Revised National Tuberculosis Control Programme (RNTCP) in India, 2013.

Error bars depict 95% confidence intervals.

Fig 9. The tuberculosis cascade of care for new smear-negative tuberculosis patients detected and treated by the Revised National Tuberculosis Control Programme (RNTCP) in India, 2013.

Error bars depict 95% confidence intervals.

Fig 10. The tuberculosis cascade of care for retreatment smear-positive tuberculosis patients detected and treated by the Revised National Tuberculosis Control Programme (RNTCP) in India, 2013.

Error bars depict 95% confidence intervals.

Fig 11. The tuberculosis cascade of care for multidrug-resistant tuberculosis (MDR TB) patients detected and treated by the Revised National Tuberculosis Control Programme (RNTCP) in India, 2013.

Error bars depict 95% confidence intervals for each estimate.