Table 14:
Sensitivity Scenario Analysis Results: Best-Ranked Strategiesa
| Parameter/Assumption: a. Base case analysis b. Scenario analysis |
Group CBT by Nonphysician vs. Usual Care ICER ($/QALY)/INBb > 0 or INB < 0 ($) | Individual CBT by Nonphysician vs. Group CBT by Nonphysician ICER ($/QALY)/INB > 0 or INB < 0 ($) |
|---|---|---|
| 1. Population | ||
| a. Base case: MDD and GAD | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: GAD only | b. 1,783/INB > 0 | b. 147, 657/INB < 0 |
| 2. Initial disease severity | ||
| a. Base case: Mild and moderate to severe MDD | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) Mild MDD | (i) 1,973/INB > 0 | (i) 197,507/INB < 0 |
| (ii) Moderate to severe MDD | (ii) 8,840/INB > 0 | (ii) 183,074/INB < 0 |
| 3. Efficacy of interpersonal therapy | ||
| a. Base case: CBT | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: Interpersonal therapy | b. Cost-saving/INB > 0 | b. 312,234/INB < 0 |
| 4. Efficacy of CBT | ||
| a. Base case: RR_CBT | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: 0.25 × RR_CBT | b. 7,404/INB > 0 | b. 155,814/INB < 0 |
| 5. Dropout | ||
| a. Base case: see Table 4 | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) 2 × base case probability | (i) 12,839/INB > 0 | (i) 164,239/INB < 0 |
| (ii) 0.5 × base case probability | (ii) Cost-saving/INB > 0 | (ii) 249,960/INB < 0 |
| 6. Probability of not being well after dropout | ||
| a. Base case: 0.33 | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) 2 × base case probability | (i) Cost-saving/INB > 0 | (i) 223,638/INB < 0 |
| (ii) 0.5 × base case probability | (ii) 9,391/INB > 0 | (ii) 185,319/INB < 0 |
| 7. Rate of recurrence | ||
| a. Base case: Eaton 2008100 | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: NEMESIS99 | b. 7, 035/INB > 0 | b. 259,382/INB < 0 |
| 8. Rate of hospitalization | ||
| a. Base case: 0.10 | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) 2 × base case rate | (i) 2,904/INB > 0 | (i) 191,998/INB < 0 |
| (ii) 0.5 × base case rate | (ii) 4,137/INB > 0 | (ii) 192,941/INB < 0 |
| 9. Additional disutility owing to past MDD | ||
| a. Base case: Yes | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: No | b. 3,751/INB > 0 | b. 210,287/INB < 0 |
| 10. Utility associated with CBT treatment | ||
| a. Base case: 0.85 | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: 0.765 | b. 6,486/INB > 0 | b. 183,772/INB < 0 |
| 11. Number of CBT sessions (N) | ||
| a. Base case: N = 14 | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) N = 6 | (i) 781/INB > 0 | (i) 106,181/INB < 0 |
| (i) N = 20 | (ii) 7,539/INB > 0 | (ii) 306, 297/INB < 0 |
| 12. Costs of physician-provided CBTc | ||
| a. Base case: Psychiatrist | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: GPc | b. 3,175/INB > 0 | b. 131,431/INB < 0c |
| 13. Costs of nonphysician-provided CBT, salary-based | ||
| a. Base case: $130,000/year, 30% benefits, FTE: 1,658 hours/year | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) $130,000/year, 17% benefits | (i) 2,675/INB > 0 | (i) 161,132/INB < 0 |
| (ii) $110,000/year, 30% benefits | (ii) 3,129/INB > 0 | (ii) 172,929/INB < 0 |
| (iii) $110,000/year, 17% benefits | (iii) 2,139/INB > 0 | (iii) 144,009/INB < 0 |
| 14. Costs of CBT, 2 providers | ||
| a. Base case: Psychiatrist or highest paid nonphysician | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: GP or lowest paid nonphysician | b. 2,133/INB > 0 | b. 144,057/INB < 0 |
| 15. Direct medical costs | ||
| a. Base case: All treatment costs | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: CBT treatment costs | b. 16,763/INB > 0 | b. 206, 792/INB < 0 |
| 16. Costs of complex depression | ||
| a. Base case: Responders | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: Nonresponders | b. Cost-saving/INB > 0 | b. 188,031/INB < 0 |
| 17. Costs of follow-up | ||
| a. Base case:100%, regular visits | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: Reduction of follow-up visits and costs by | b. | b. |
| (i) 25% | (i) 1,825/INB > 0 | (i) 192,925/INB < 0 |
| (ii) 50% | (ii) Cost-saving/INB > 0 | (ii) 193,232/INB < 0 |
| (iii) 75% | (iii) Cost-saving/INB > 0 | (iii) 193,593/INB < 0 |
| 18. Discount rate | ||
| a. Base case: 1.5% | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenario: 5% | b. 4,058/INB > 0 | b. 191,704/INB < 0 |
| 19. Time horizon | ||
| a. Base case: 5 years | a. 3,175/INB > 0 | a. 192,618/INB < 0 |
| b. Scenarios: | b. | b. |
| (i) 1 yeard | (i) 16,278/INB > 0 | (i) 103,891/INB < 0 |
| (ii) 2 years | (ii) 9,979/INB > 0 | (ii) 163,071/INB < 0 |
| (iii) 10 years | (iii) Cost-saving/INB > 0 | (iii) 96,319/INB < 0 |
| (iv) 20 years | (iv) Cost-saving/INB > 0 | (iv) 33,935/INB > 0 |
| (v) Lifetime | (v) Cost-saving/INB > 0 | (v) 5,126/INB > 0 |
Abbreviations: CBT, cognitive behavioural therapy; FTE, full-time equivalent; GAD, generalized anxiety disorder; GP, general practitioner; ICER, incremental cost-effectiveness ratio; INB, incremental net benefit; MDD, major depressive disorder; NEMESIS, Netherlands Mental Health Survey and Incidence Study; QALY, quality-adjusted life-year; RR, relative risk.
a
All costs in 2017 Canadian dollars.
b
INB = incremental effects × $50,000/QALY – incremental costs; if INB < 0, then the strategy is not cost-effective.
c
Individual CBT provided by a nonphysician was more costly than individual CBT provided by a physician (see Table 13) and was eliminated from ranking; the ICER is still over $100,000/QALY.
d
All costs and effects were discounted at 1.5% in the base case analysis and all scenarios, except for scenario 19 using a 1-year time horizon (in this case, discounting was deemed inappropriate).