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Published on: April 9, 2012
Xpert Ultra stool testing to diagnose tuberculosis in children in Ethiopia and Indonesia: a model-based
Nyashadzaishe Mafirakureva1, Eveline Klinkenberg2,3, Ineke Spruijt4
1ScHARR, The University of Sheffield, Sheffield, UK n.mafirakureva@sheffield.ac.uk.
Insights
Implementing the simple one-step (SOS) stool method for diagnosing paediatric tuberculosis (TB) significantly improves diagnostic accuracy and reduces mortality. This approach is highly cost-effective for primary healthcare settings in Ethiopia and Indonesia.
Area of Science:
- Public Health
- Infectious Disease Diagnostics
- Health Economics
Background:
- The World Health Organization (WHO) recommends GeneXpert MTB/Rif (Xpert) for paediatric tuberculosis (TB) diagnosis.
- The simple one-step (SOS) stool method facilitates Xpert testing at the primary healthcare (PHC) level.
- Current diagnostic strategies for paediatric TB in low-resource settings require optimization for improved outcomes.
Purpose of the Study:
- To model the impact and cost-effectiveness of implementing the SOS stool method for paediatric TB diagnosis at the PHC level in Ethiopia and Indonesia.
- To compare the SOS stool method implementation against the standard of care (smear microscopy).
Main Methods:
- Decision tree modeling was employed to simulate patient care and referral pathways.
- Model parameters were derived from ongoing studies, surveillance data, systematic literature reviews, and expert opinions.
- Cost-effectiveness was assessed using incremental costs per disability-adjusted life-year (DALY) averted.
Main Results:
- The SOS stool method intervention increased TB diagnostic sensitivity by 19-25%, leading to a 14-20% relative reduction in mortality.
- The intervention resulted in increased initiation of anti-TB treatment (ATT) by 18-25%, with 85% initiated at the PHC level.
- Incremental cost-effectiveness ratios were US$132/DALY averted in Ethiopia and US$94/DALY averted in Indonesia, with high probabilities of cost-effectiveness at standard thresholds.
Conclusions:
- The integration of the SOS stool method into national TB diagnostic algorithms is projected to be cost-effective in Ethiopia and Indonesia.
- This approach enhances diagnostic capabilities at the primary healthcare level, improving treatment initiation and patient outcomes for paediatric TB.
Objectives:
The WHO currently recommends stool testing using GeneXpert MTB/Rif (Xpert) for the diagnosis of paediatric tuberculosis (TB). The simple one-step (SOS) stool method enables processing for Xpert testing at the primary healthcare (PHC) level. We modelled the impact and cost-effectiveness of implementing the SOS stool method at PHC for the diagnosis of paediatric TB in Ethiopia and Indonesia, compared with the standard of care.
Setting:
All children (age <15 years) presenting with presumptive TB at primary healthcare or hospital level in Ethiopia and Indonesia.
Primary Outcome:
Cost-effectiveness estimated as incremental costs compared with incremental disability-adjusted life-years (DALYs) saved.
Methods:
Decision tree modelling was used to represent pathways of patient care and referral. We based model parameters on ongoing studies and surveillance, systematic literature review, and expert opinion. We estimated costs using data available publicly and obtained through in-country expert consultations. Health outcomes were based on modelled mortality and discounted life-years lost.
Results:
The intervention increased the sensitivity of TB diagnosis by 19-25% in both countries leading to a 14-20% relative reduction in mortality. Under the intervention, fewer children seeking care at PHC were referred (or self-referred) to higher levels of care; the number of children initiating anti-TB treatment (ATT) increased by 18-25%; and more children (85%) initiated ATT at PHC level. Costs increased under the intervention compared with a base case using smear microscopy in the standard of care resulting in incremental cost-effectiveness ratios of US$132 and US$94 per DALY averted in Ethiopia and Indonesia, respectively. At a cost-effectiveness threshold of 0.5×gross domestic product per capita, the projected probability of the intervention being cost-effective in Ethiopia and Indonesia was 87% and 96%, respectively. The intervention remained cost-effective under sensitivity analyses.
Conclusions:
The addition of the SOS stool method to national algorithms for diagnosing TB in children is likely to be cost-effective in both Ethiopia and Indonesia.
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