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Table 1 Select model parameters

From: Estimating the impact of a novel drug regimen for treatment of tuberculosis: a modeling analysis of projected patient outcomes and epidemiological considerations

Parameter Estimate, South Africa Range in sensitivity analysis References and notes
Fraction of TB cases previously treated for TB 10% 8–13% [9]
Fraction of TB cases with HIV 60% 54–66% [1]
Baseline prevalence of RR, new cases 3.4% 2.5–4.3% [1]
Baseline prevalence of RR, cases previously treated for TB 7.1% 4.8–9.5% [1]
Prevalence of pyrazinamide resistance, if RR 44% 33–55% [7]
Prevalence of pyrazinamide resistance, if RS 1.3% 0.8–2.0% [7]
Prevalence of any moxifloxacin resistance, if RR 9.5% 4–18% [7, 10]
Prevalence of high-level moxifloxacin resistance, if RR 5.9% 2–12% [7, 10]
Prevalence of any moxifloxacin resistance, if RS 0.4% 0–0.9% [7, 10]
Mean time from TB onset to TB diagnosis 9 months 6–15 Incidence:prevalence ratio estimates [1]
Pretreatment loss to follow up 10% 5–20% [11]
Monthly loss to follow up during treatment 1% 0.8–2% [12]
Monthly TB mortality, untreated active TB 2.1% 2.3–2.8% [1, 13]
Present-day Xpert MTB/RIF coverage, new patients 70% 60–80% [1] with projected increase to 2019
Present-day Xpert MTB/RIF coverage, patients previously treated for TB 75% 60–90% [1] with projected increase to 2019
Relapse after six months HRZE or four months of BPaMZ (assuming drug susceptibility)a 6.3% 2–12% [4, 14,15,16]; See Additional File 1.
Odds ratio of cure from moxifloxacin-containing regimen, low-level versus high-level moxifloxacin resistance 1.7 1.3–2.2 [17], based on levofloxacin vs ofloxacin when ofloxacin resistant
Risk of acquired RR after HRZE b 0.005 0.002–0.15 [18]
Risks of acquired B, Pa, or M after BPaMZ b 0.002 0–0.01 Assumed
Risk of acquired moxifloxacin resistance after conventional multidrug-resistant TB regimen 0.04 0.005–0.08 [19]
  1. TB = tuberculosis, RS = rifampin susceptible, RR = rifampin resistant, Z = pyrazinamide, M = moxifloxacin. B = bedaquiline, Pa = pretomanid, HRZE = standard first-line regimen of isoniazid, rifampin, pyrazinamide, ethambutol.
  2. a The probability of successful treatment is reduced when resistance is present to one or more drugs in the regimen prescribed, or when duration is changed (shortened due to loss to follow up, or extended to six months for patients with RR-TB receiving BPaMZ), as shown in part b of the Table
  3. b Parameter value shown is the risk if initially susceptible to R and Z (HRZE), or to B, Pa, and M (BPaMZ). Risk of acquired resistance to remaining drugs is increased for M. tuberculosis strains already resistant to one or more of these drugs in the regimen used; see Additional File 1 for details