Table 1.
Inputs for a cost-effectiveness model comparing 3HP with direct observation by a health care worker to 9H for treatment of LTBI; values are those used in the base case analysis
| Cost | Societal cost US$ | Health system cost US$ | Source/reference* |
|---|---|---|---|
| LTBI treatment | |||
| Cost of initial visit (excluding medicines) | 203 | 166 | Nashville Public Health Department |
| Cost per follow-up visit (excluding medicines) | 50 | 28 | Nashville Public Health Department |
| DOT, cost per dose | 20 | 18 | Nashville Public Health Department |
| Cost per dose, 9H | 0.05 | 0.05 | Department of Veterans Affairs |
| Cost per dose, 3HP | 12.31 | 12.31 | Department of Veterans Affairs |
| LTBI drug toxicity | 8, 9 | ||
| Toxicity without hospitalization | 169 | 169 | |
| Toxicity with hospitalization | 6 650 | 5 677 | |
| Active TB | |||
| Diagnostic costs | 298 | 259 | 9–11 |
| Out-patient treatment | 2 958 | 2 725 | |
| Hospitalization (if required) | 28 831 | 25 495 | |
| Quality of life adjustments | QALY lost per year | 8 | |
|
|
|||
| Health state | |||
| LTBI treatment | 0.03 | ||
| Drug toxicity | 0.25 | ||
| Hospitalization | 0.50 | ||
| Treatment of active TB | 0.10 | ||
| Previous active TB | 0.05 | ||
| Baseline TB risk, years 1–3 after treatment start | % of patients | Annual risk of progression to TB % | |
|
|
|||
| 9H doses taken | Tuberculosis Trials Consortium Data Management Center | ||
| 0–90 | 17 | 0.36 | |
| 91–240 | 15 | 0.28 | |
| 241+ | 68 | 0.08 | |
| 3HP doses taken | Tuberculosis Trials Consortium Data Management Center | ||
| 0–8 | 16 | 0.13 | |
| 9+ | 84 | 0.05 | |
| LTBI drug toxicity, probabilities per treatment start | 9H | 3HP | |
|
|
|||
| Probability of drug toxicity | 5.5 | 8.2 | 3 |
| Probability of hospitalization from toxicity | 0.1 | 0.3 | 3 |
| Probability of death from drug toxicity | 0.014 | 0.014 | 12, 13 |
| Other | Value | ||
|
|
|||
| Age at LTBI treatment start | Distribution | 3 | |
| Probability of death from TB | 5.8% | Tuberculosis Epidemiologic Studies Consortium, CDC | |
| Background mortality rate | Age-dependent | 14 | |
| Patient time valuation (2010 US$) | |||
| Hourly (clinic visits) | $12.73 | 15 | |
| Daily (overnight hospitalization) | $139.00 | 16 | |
| Probability of hospitalization for TB | 0.49 | 9 | |
| Secondary TB cases per primary case | 0.46 | 17–20 | |
*
Unreferenced sources refer to unpublished data; see Acknowledgements.
3HP = 3 months of weekly isoniazid plus rifapentine; 9H = 9 months of daily, self-administered isoniazid; LTBI = latent tuberculous infection; DOT = directly observed treatment; TB = tuberculosis; CDC = Centers for Disease Control and Prevention.