Eligibility for a Shorter Treatment Regimen for Multidrug-resistant Tuberculosis in the United States, 2011-2016.

Background. In 2016, the World Health Organization (WHO) recommended a shorter (9-12 month) multidrug-resistant tuberculosis (MDR-TB) treatment regimen (as compared to the conventional 18-24 month regimen) for patients without extrapulmonary TB, pregnancy, a previous second-line TB medication exposure, or drug resistance to pyrazinamide, ethambutol, kanamycin, moxifloxacin, ethionamide, or clofazimine. The recommendation was based on successful clinical trials conducted in Asia and Africa, but studies, using mainly European data, have shown few patients in higher-resource settings would meet WHO eligibility criteria. Methods. We assessed eligibility for the shorter regimen among US MDR-TB cases that had full drug susceptibility testing (DST) results and were reported during 2011-2016 to the US National TB Surveillance System. We estimated costs by applying the eligibility criteria for the shorter regimen, and proportional inpatient/outpatient costs from a previous, population-based study, to all MDR-TB patients reported to the National TB Surveillance System. Results. Of 586 reported MDR-TB cases, 10% (59) were eligible for the shorter regimen. Of 527 ineligible patients, 386 had full DST, of which 246 were resistant to ethambutol and 217 were resistant to pyrazinamide. Compared with conventional MDR-TB treatment, implementing the shorter regimen would have reduced the US annual societal MDR-TB cost burden by 4%, but the cost burden for eligible individuals would have been reduced by 37-46%. Conclusions. Relying on full DST use, our analysis found a minority of US MDR-TB patients would have been eligible for the shorter regimen. Cost reductions would have been minimal for society, but large for eligible individuals.