Background
Methods
Overview
Perspective
Cohort at baseline
LTBI therapy
Natural history
Program performance
Health state utilities
Costs
Variable | Cost | Source |
---|---|---|
New patient doctor visit | 111.50 | Medicare, 2004, Note 1 |
Established patient visit | 61.25 | Medicare, 2004, Note 1 |
Tuberculin skin test | 11.78 | Medicare, 2004, Note 1 |
Initial chest X-ray | 39.68 | Medicare, 2004, Note 1 |
Sputum collection | 17.80 | Medicare, 2004, Note 1 |
Specimen concentration | 9.33 | Medicare Part B, Note 2 |
AFB smear | 7.50 | Medicare Part B, Note 2 |
Sputum culture | 14.42 | Medicare Part B, Note 2 |
Sensitivity testing | 7.38 | Medicare Part B, Note 2 |
Mycobacterial identification | 15.29 | Medicare Part B, Note 2 |
Isoniazid, 100 tablets | 8.90 | Medicaid Federal Upper Limit price |
Chemotherapy for active TB | 1118 | Drug prices Red Book, 2004; ATS recommendations; Note 3 |
Nurse assessment, 1/4 hr | 8.40 | Medi-Cal |
Liver function tests | 11.42 | Medicare Part B, Note 2 |
TB hospitalization episode | 25 834 | Note 4; based on CDC unpublished data |
Hepatitis hospital stay | 10 662 | Note 5; [61] |
Complete blood count | 9.04 | Medicare Part B, Note 2 |
Renal function panel | 12.13 | Medicare Part B, Note 2 |
Directly observed therapy (DOT) | 19.23 | Medi-Cal |
Disease control investigation | 387.02 | [51,52]; Appendix |
Letter mailed | 10.80 | [42]; Note 6 |
Phone call (community worker) | 13.24 | [42]; Note 6 |
Home visit (community worker) | 39.57 | [42]; Note 6 |
Base case scenario, and uncertainty and sensitivity analyses
Description | Values |
---|---|
Mean age (Note 1)
| 53.3 |
INH resistance
| 0.129 |
Drug-induced hepatitis rates
| 0.0008 to 0.0028 |
Efficacy of completed regimen (Note 2)
| 70% |
Mean time to passive diagnosis
| 74 days |
TST sensitivity
| 93% |
TST specificity (Note 3)
| 99% |
Probability of fast progression to TB after infection | 0.05 |
Probability of finding a TB contact | 80% |
Fraction of individuals with B-notification
| |
with active disease | 3% |
in class TB4 | 60% |
in class TB2 | 22% |
Fraction of
| |
baseline active cases smear positive | 7.5% |
TB4s eligible for LTBI therapy | 63% |
Hospitalization probability
| |
actively detected smear-positive | 0.35 |
actively detected smear-negative | 0.081 |
passively detected smear-positive | 0.66 |
passively detected smear-negative | 0.51 |
Transmission (new infections per year)
| |
smear-positive source case | 8 |
smear-negative source case | 0.8 |
Attrition cascade for domestic follow-up after B-notification
| |
Evaluation rate | 60% |
Starting rate, LTBI therapy | 80% |
Completion rate, LTBI therapy | 75% |
Reactivation rate at baseline, Note 4 | |
class TB4 | 600 |
class TB2 | 217 |
Results
Base case scenario
Sensitivity analysis
Evaluation Rate | Starting Rate | Completion Rate | QALYs Saved | Net costs (1000s) | Cases Averted | TB Deaths Averted |
---|---|---|---|---|---|---|
45% | - | - | 1.9 (0.09) | -11 (0.5) | 0.18 (0.02) | 0.059 (0.003) |
65% | - | - | 2.9 (0.08) | -16 (0.5) | 0.26 (0.02) | 0.089 (0.004) |
85% | - | - | 3.9 (0.08) | -22 (0.5) | 0.38 (0.02) | 0.12 (0.003) |
Evaluation Rate | Starting Rate | Completion Rate | QALYs Saved | Net costs (1000s) | Cases Averted | TB Deaths Averted |
---|---|---|---|---|---|---|
45% | 35% | 30% | 1.1 (0.1) | -3.2 (1) | 0.79 (0.06) | 0.039 (0.005) |
45% | 35% | 55% | 0.63 (0.2) | -2.4 (0.7) | 0.95 (0.05) | 0.018 (0.008) |
45% | 35% | 75% | 0.79 (0.1) | -1.9 (0.9) | 1 (0.05) | 0.032 (0.007) |
45% | 45% | 30% | 0.85 (0.2) | -3.6 (0.7) | 0.97 (0.04) | 0.028 (0.009) |
45% | 45% | 55% | 1.3 (0.3) | -3.8 (0.9) | 1.1 (0.05) | 0.048 (0.01) |
45% | 45% | 75% | 1.4 (0.2) | -4.5 (0.8) | 1.4 (0.05) | 0.058 (0.01) |
45% | 80% | 30% | 1.8 (0.1) | -6.6 (1) | 1.7 (0.05) | 0.07 (0.006) |
45% | 80% | 55% | 2.5 (0.2) | -6.7 (1) | 2.1 (0.04) | 0.088 (0.009) |
45% | 80% | 75% | 2.4 (0.2) | -6.9 (1) | 2.4 (0.06) | 0.09 (0.01) |
65% | 35% | 30% | 1.3 (0.2) | -5.2 (1) | 1.2 (0.04) | 0.049 (0.009) |
65% | 35% | 55% | 1.7 (0.2) | -3.4 (1) | 1.3 (0.05) | 0.065 (0.009) |
65% | 35% | 75% | 1.4 (0.1) | -3.3 (0.7) | 1.5 (0.03) | 0.048 (0.009) |
65% | 45% | 30% | 1 (0.2) | -6.1 (2) | 1.4 (0.08) | 0.04 (0.007) |
65% | 45% | 55% | 2.1 (0.2) | -6.1 (0.7) | 1.8 (0.04) | 0.077 (0.01) |
65% | 45% | 75% | 2.2 (0.2) | -5.5 (0.9) | 1.9 (0.03) | 0.086 (0.009) |
65% | 80% | 30% | 2.5 (0.2) | -11 (2) | 2.6 (0.07) | 0.095 (0.008) |
65% | 80% | 55% | 3 (0.2) | -10 (0.8) | 3 (0.04) | 0.11 (0.01) |
65% | 80% | 75% | 3.5 (0.1) | -8.3 (0.6) | 3.4 (0.03) | 0.13 (0.007) |
85% | 35% | 30% | 1.7 (0.2) | -5.6 (1) | 1.4 (0.06) | 0.065 (0.007) |
85% | 35% | 55% | 2.2 (0.2) | -7.4 (1) | 1.8 (0.04) | 0.089 (0.008) |
85% | 35% | 75% | 2.2 (0.3) | -5.6 (0.7) | 1.9 (0.04) | 0.087 (0.01) |
85% | 45% | 30% | 2 (0.2) | -8.1 (0.9) | 1.9 (0.04) | 0.074 (0.01) |
85% | 45% | 55% | 2.3 (0.2) | -8 (1) | 2.4 (0.04) | 0.091 (0.008) |
85% | 45% | 75% | 2.5 (0.2) | -6.6 (0.8) | 2.6 (0.04) | 0.093 (0.01) |
85% | 80% | 30% | 3.7 (0.2) | -14 (1) | 3.4 (0.05) | 0.14 (0.01) |
85% | 80% | 55% | 4.1 (0.1) | -13 (0.7) | 3.9 (0.03) | 0.15 (0.009) |
85% | 80% | 75% | 4.5 (0.2) | -12 (0.9) | 4.4 (0.04) | 0.16 (0.008) |
Evaluation Rate | Starting Rate | Completion Rate | QALYs saved | Net costs (1000s) | Cases Averted | TB Deaths Averted |
---|---|---|---|---|---|---|
45% | 35% | 30% | 0.12 (0.08) | 0.022 (0.4) | 0.2 (0.02) | 0.0073 (0.005) |
45% | 35% | 55% | 0.22 (0.1) | 0.43 (0.4) | 0.2 (0.02) | 0.011 (0.006) |
45% | 35% | 75% | 0.25 (0.07) | 0.09 (0.5) | 0.23 (0.02) | 0.013 (0.004) |
45% | 45% | 30% | 0.17 (0.08) | 0.34 (0.2) | 0.2 (0.02) | 0.013 (0.004) |
45% | 45% | 55% | 0.32 (0.06) | 0.86 (0.4) | 0.24 (0.02) | 0.016 (0.002) |
45% | 45% | 75% | 0.23 (0.06) | 1.1 (0.6) | 0.28 (0.02) | 0.011 (0.003) |
45% | 80% | 30% | 0.35 (0.1) | 1.4 (0.5) | 0.33 (0.02) | 0.014 (0.006) |
45% | 80% | 55% | 0.42 (0.1) | 2.3 (0.5) | 0.4 (0.02) | 0.018 (0.005) |
45% | 80% | 75% | 0.55 (0.06) | 2.4 (0.4) | 0.45 (0.02) | 0.025 (0.004) |
65% | 35% | 30% | 0.21 (0.07) | 0.24 (0.4) | 0.21 (0.02) | 0.01 (0.003) |
65% | 35% | 55% | 0.1 (0.07) | 1.3 (0.4) | 0.25 (0.02) | 0.0025 (0.004) |
65% | 35% | 75% | 0.28 (0.07) | 1.9 (0.2) | 0.29 (0.01) | 0.016 (0.004) |
65% | 45% | 30% | 0.26 (0.08) | 1.1 (0.4) | 0.27 (0.01) | 0.01 (0.005) |
65% | 45% | 55% | 0.44 (0.07) | 0.87 (0.4) | 0.36 (0.03) | 0.019 (0.003) |
65% | 45% | 75% | 0.62 (0.06) | 1.7 (0.4) | 0.42 (0.02) | 0.026 (0.004) |
65% | 80% | 30% | 0.51 (0.04) | 1.6 (0.3) | 0.49 (0.01) | 0.024 (0.003) |
65% | 80% | 55% | 0.72 (0.09) | 1.9 (0.5) | 0.64 (0.03) | 0.035 (0.004) |
65% | 80% | 75% | 0.64 (0.07) | 3.7 (0.3) | 0.69 (0.03) | 0.028 (0.003) |
85% | 35% | 30% | 0.34 (0.08) | 1 (0.4) | 0.3 (0.02) | 0.015 (0.004) |
85% | 35% | 55% | 0.34 (0.1) | 1.4 (0.5) | 0.32 (0.02) | 0.014 (0.004) |
85% | 35% | 75% | 0.29 (0.07) | 2.4 (0.5) | 0.37 (0.02) | 0.013 (0.004) |
85% | 45% | 30% | 0.37 (0.07) | 1 (0.5) | 0.36 (0.02) | 0.016 (0.004) |
85% | 45% | 55% | 0.36 (0.05) | 2.4 (0.6) | 0.43 (0.02) | 0.015 (0.003) |
85% | 45% | 75% | 0.49 (0.08) | 3 (0.6) | 0.46 (0.03) | 0.022 (0.005) |
85% | 80% | 30% | 0.59 (0.07) | 2 (0.3) | 0.66 (0.02) | 0.026 (0.002) |
85% | 80% | 55% | 0.77 (0.09) | 3.9 (0.5) | 0.79 (0.02) | 0.034 (0.003) |
85% | 80% | 75% | 0.85 (0.06) | 5.3 (0.4) | 0.85 (0.02) | 0.036 (0.003) |
Parameter varied | Value | Active cases | Add TB4s | Overall (all) | ||||
---|---|---|---|---|---|---|---|---|
Base | New | QALYs | Cost | QALYs | Cost | QALYs | Cost | |
None | - | - | 4.1 (0.3) | -17 (1.6) | 2.9 (0.1) | -10 (0.7) | 7.7 (0.3) | -25 (1.5) |
Passive treatment delay (days) | 74 | 100 | 5.8 (0.2) | -14 (1.4) | 3.7 (0.2) | -12 (1) | 10 (0.3) | -22 (1.7) |
Screening delay (days) | 0 | 14 | 4.4 (0.3) | -17 (1.4) | 3.2 (0.2) | -11 (1.1) | 8.1 (0.2) | -25 (1.7) |
Fraction of active cases | 3% | 6% | 8.1 (0.3) | -290 (2.2) | 3.1 (0.2) | -11 (0.7) | 12 (0.4) | -290 (2.5) |
Baseline smear-positive rate | 7.5% | 15% | 5.2 (0.3) | -9.6 (0.9) | 3.3 (0.3) | -11 (0.8) | 9.3 (0.4) | -18 (0.9) |
Transmission rate (Note 1) | 8 | 16 | 4.2 (0.3) | -22 (1.6) | 3.4 (0.2) | -12 (1) | 8.3 (0.3) | -33 (1.6) |
Hospitalization rates | ||||||||
Actively detect, smear pos. | 0.35 | 0.66 | 4.1 (0.2) | 0.8 (1) | 3.6 (0.2) | -11 (1) | 8.3 (0.3) | -7.2 (1.6) |
Passively detect, smear pos. | 0.66 | 0.33 | 3.8 (0.13) | +8.3 (1.7) | 3.4 (0.2) | -1.0 (0.7) | +7.9 (0.3) | +12 (2.3) |
Actively detect, smear neg. | 0.081 | 0.162 | 4.1 (0.2) | +27 (0.7) | 3 (0.18) | -8.6 (0.6) | 7.7 (0.3) | +22 (1.2) |
Passively detect, smear neg. | 0.51 | 0.255 | 3.5 (0.3) | +140 (0.6) | 3.2 (0.15) | 1.5 (0.8) | 7.3 (0.3) | +150 (1) |
Reactivation rates, Note 2 | ||||||||
TB4s | 600 | 430 | 4 (0.3) | -16 (1.3) | 2.5 (0.15) | 1.0 (0.7) | 7.1 (0.3) | -12 (2) |
Cost multipliers | ||||||||
Hospitalization costs | same | +20% | 4.1 (0.3) | -67 (1.5) | 3 (0.13) | -16 (0.9) | 7.8 (0.3) | -83 (1.5) |
Costs, excluding hospital | same | +20% | 3.4 (0.18) | +14 (0.9) | 3.5 (0.2) | -4.6 (1.1) | 7.7 (0.3) | +14 (1.6) |
Selected costs | ||||||||
Nurse refill visit | 16.80 | 8.40 | 3.7 (0.2) | -17 (1.1) | 3.3 (0.13) | -26 (0.8) | 7.5 (0.3) | -43 (1.4) |
DOT visit | 19.23 | 25.00 | 4.5 (0.2) | -16 (1.2) | 3.0 (0.2) | -11 (1) | 7.8 (0.4) | -24 (1.8) |
TST specificity | 0.99 | 0.875 | 4.1 (0.2) | -14 (1.1) | 3.0 (0.2) | -11 (0.9) | 7.6 (0.3) | -21 (1.2) |
Fraction INH resistant | 0.13 | 0.2 | 3.9 (0.3) | -14 (1) | 2.3 (0.2) | -5.3 (0.8) | 6.7 (0.4) | -16 (0.9) |
Risk multiplier, severe hepatitis | 1 | 3 | 3.9 (0.3) | -16 (0.9) | 3.0 (0.15) | -5.4 (0.5) | 7.6 (0.3) | -17 (1) |
Selected disutilities | ||||||||
Hepatitis hospitalization | 0.4 | 0.9 | 4.3 (0.3) | -15 (1.5) | 3.1 (0.2) | -10 (0.9) | 8.0 (0.3) | -23 (1.6) |
Outpatient hepatitis | 0.265 | 0.5 | 4.3 (0.2) | -16 (1.3) | 3.1 (0.17) | -9.9 (1.1) | 8.0 (0.3) | -24 (2) |
Other INH side-effects | 0.1 | 0.2 | 3.9 (0.2) | -15 (1) | 2.9 (0.13) | -10 (0.7) | 7.4 (0.2) | -22 (1.2) |
Untreated TB | 0.1 | 0.2 | 4.8 (0.19) | -15 (1) | 3.6 (0.15) | -10 (0.9) | 9.0 (0.3) | -22 (1.5) |
Lost QALYs, INH one month | 0 | 0.01 | 4.5 (0.3) | -15 (1.1) | -15 (0.2) | -9.9 (0.8) | -16 (0.4) | -22 (0.9) |
Disutility multipliers | ||||||||
TB hospitalization | 1 | 0.5 | 4.0 (0.19) | -16 (1.4) | 3.3 (0.1) | -10 (1) | 7.9 (0.2) | -24 (1.3) |
Outpatient TB | 1 | 0.5 | 4.2 (0.3) | -16 (1.3) | 3.4 (0.2) | -8 (0.7) | 8.3 (0.3) | -21 (1.6) |
Discount rate per year | 0.03 | 0.05 | 3.2 (0.15) | -13 (1) | 2.4 (0.13) | -6.9 (1.2) | 5.9 (0.2) | -16 (1.6) |
TST sensitivity | 0.93 | 0.95 | 4.2 (0.2) | -17 (1.3) | 3.4 (0.15) | -11 (1) | 8.3 (0.3) | -25 (1.7) |
TST specificity | 0.99 | 0.95 |
Percent Active TB | Percent TB4 | Percent TB2 | QALYs saved | Net cost | Cases averted |
---|---|---|---|---|---|
1.5 | 30 | 15 | 4.3 (0.2) | 66 (1.1) | 2.3 (0.05) |
1.5 | 30 | 30 | 4.4 (0.3) | 67 (1.5) | 2.7 (0.07) |
1.5 | 30 | 45 | 5.4 (0.3) | 72 (1.2) | 3.0 (0.07) |
1.5 | 45 | 15 | 5.0 (0.4) | 88 (1.3) | 3.0 (0.09) |
1.5 | 45 | 30 | 5.2 (0.4) | 90 (1.2) | 3.4 (0.07) |
1.5 | 45 | 45 | 6.0 (0.2) | 94 (0.9) | 3.9 (0.06) |
1.5 | 60 | 15 | 5.7 (0.4) | 110 (1.1) | 3.8 (0.07) |
1.5 | 60 | 30 | 6.2 (0.3) | 120 (1.6) | 4.0 (0.07) |
1.5 | 75 | 15 | 6.4 (0.3) | 130 (1.9) | 4.5 (0.11) |
3.0 | 30 | 15 | 6.2 (0.2) | -67 (1.2) | 2.5 (0.06) |
3.0 | 30 | 30 | 6.4 (0.3) | -64 (1.4) | 2.8 (0.06) |
3.0 | 30 | 45 | 7.0 (0.2) | -64 (1.2) | 3.3 (0.05) |
3.0 | 45 | 15 | 6.8 (0.3) | -46 (1.9) | 3.1 (0.06) |
3.0 | 45 | 30 | 7.2 (0.4) | -42 (1.4) | 3.6 (0.11) |
3.0 | 45 | 45 | 7.5 (0.4) | -40 (1.1) | 4.0 (0.07) |
3.0 | 60 | 15 | 7.4 (0.3) | -25 (2) | 4.0 (0.15) |
3.0 | 60 | 30 | 8.5 (0.3) | -21 (1.8) | 4.5 (0.1) |
3.0 | 75 | 15 | 9.1 (0.3) | -1.4 (1.6) | 4.8 (0.07) |
Fraction of active cases | 40% TB4s | 60% TB4s | ||
---|---|---|---|---|
Cost per QALY saved | Cost per case averted | Cost per QALY saved | Cost per case averted | |
0% | $72 000 | $72 000 | $64 000 | $66 000 |
0.5% | $47 000 | $57 000 | $45 000 | $53 000 |
1.0% | $30 000 | $41 000 | $31 000 | $41 000 |
1.5% | $17 000 | $27 000 | $19 000 | $29 000 |
2.0% | $7 000 | $12 000 | $10 000 | $17 000 |
2.5% | cost saving | cost saving | $3000 | $5 000 |
3.0% | cost saving | cost saving | cost saving | cost saving |
Resource allocation
Beginning with ... | Choose between ... | Best choice | |
---|---|---|---|
1. | Treat only active cases; detect them only passively | (1) Offer LTBI treatment to TB2s or TB4s, or (2) send letters to improve evalua tion | Send letters (2.7 QALYs gained, $10 000 in net sav ings) |
2. | Send letters; treat active cases | (1) Offer LTBI treatment to TB2s, (2) Offer LTBI treatment to TB4s, or (3) make phone calls to improve evaluation rates | Treat TB4s (3.2 QALYs gained, $11 000 in net savings) |
3. | Treat active cases and TB4s; improve evaluation by letters | (1) Offer LTBI treatment to TB2s, (2) make phone calls to improve evaluation rates further, (3) improve rates of starting ther apy for TB4s, or (4) improve completion rates by DOPT | Improve starting rates (1.3 QALYs saved, $1 800 in net savings) |
4. | Treat active cases and TB4s; improve evaluation rates by letters; improve starting rates | (1) send letters to improve evalua tion rates further, (2) treat TB2s, or (3) improve completion rates by DOPT | Treat TB2s (0.7 QALYs saved, $3 000 in net cost) |
5. | Treat active cases, TB2s, and TB4s; improve evaluation by letters; improve rates of starting therapy | (1) Further improve evaluation rates by phone calls, or (2) improve rates of completing therapy (by targeted DOPT) | Phone calls (0.5 QALYs saved, approximately $1 000 in net savings) |
6. | Treat active cases, TB4s, and TB2s; improve evaluation by letters and phone calls | (1) Further improve evaluation rates by home visits, or (2) improve rates of completing therapy by using targeted DOPT | Home visits (0.3 QALYs saved, approximately $1 000 in net cost) |
7. | Treat active cases, TB4s, and TB2s; improve evaluation by letters and phone calls | (1) improve rates of completing therapy by using targeted DOPT | > $100 000 per QALY saved; no further intervention |