Table 13:
Sensitivity Scenario Analysis Results: CBT Strategies Versus Usual Carea
| Parameter/Assumption: a. Base Case Analysis b. Scenario Analysis |
Group CBT by Nonphysician vs. Usual Care ICER ($/QALY)/INBb > 0 or INB < 0 ($) | Group CBT by Physician vs. Usual Care ICER ($/QALY)/INB > 0 or INB < 0 ($) | Individual CBT by Nonphysician vs. Usual Care ICER ($/QALY)/INB > 0 or INB < 0 ($) | Individual CBT by Physician vs. Usual Care ICER ($/QALY)/INB > 0 or INB < 0 ($) |
|---|---|---|---|---|
| 1. Population | ||||
| a. Base case: MDD and GAD | a. 3,175/4,994 | a. 16,729/3,590 | a. 25,914/2,942 | a. 43,443/800 |
| b. Scenario: GAD only | b. 1,783/INB > 0 | b. 11,599/INB > 0 | b. 18,396/INB > 0 | b. 31,712/INB > 0 |
| 2. Initial disease severity | ||||
| a. Base case: Mild and moderate to severe MDD | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) Mild MDD | (i) 1,973/INB > 0 | (i) 14,258/INB > 0 | (i) 23,371/INB > 0 | (i) 40,079/INB > 0 |
| (ii) Moderate to severe MDD | (ii) 8,839/INB > 0 | (ii) 23,828/INB > 0 | (ii) 32,952/INB > 0 | (ii) 52,615/INB < 0 |
| 3. Efficacy of interpersonal therapy | ||||
| a. Base case: CBT | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: Interpersonal therapy | b. Cost-saving/INB > 0 | b. 9,950/INB > 0 | b. 19,209/INB > 0 | b. 33, 671/INB > 0 |
| 4. Efficacy of CBT | ||||
| a. Base case: RR_CBT | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: 0.25 × RR_CBT | b. 7,404/INB > 0 | b. 23, 019/INB > 0 | b. 31, 455/INB > 0 | b. 51,409/INB < 0 |
| 5. Dropout | ||||
| a. Base case: see Table 4 | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) 2 × base case probability | (i) 12,839/INB > 0 | (i) 28,636/INB > 0 | (i) 36,689/INB > 0 | (i) 56,912/INB < 0 |
| (ii) 0.5 × base case probability | (ii) Cost-saving/INB > 0 | (ii) 6,674/INB > 0 | (ii) 15,100/INB > 0 | (ii) 28,622/INB > 0 |
| 6. Probability of not being well after dropout | ||||
| a. Base case: 0.33 | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) 2 × base case probability | (i) Cost-saving/INB > 0 | (i) Cost-saving/INB > 0 | (i) 7,582/INB > 0 | (i) 19,488/INB > 0 |
| (ii) 0.5 × base case probability | (ii) 9,391/INB > 0 | (ii) 24,444/INB > 0 | (ii) 33,610/INB > 0 | (ii) 53,400/INB < 0 |
| 7. Rate of recurrence | ||||
| a. Base case: Eaton 2008100 | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: NEMESIS99 | b. 7,035/INB > 0 | b. 22,863/INB > 0 | b. 34,575/INB > 0 | b. 56,344/INB < 0 |
| 8. Rate of hospitalization | ||||
| a. Base case: 0.10 | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) 2 × base case rate | (i) 2,904/INB > 0 | (i) 15,931/INB > 0 | (i) 25,119/INB > 0 | (i) 42,665/INB > 0 |
| (ii) 0.5 × base case rate | (ii) 4,137/INB > 0 | (ii) 17,143/INB > 0 | (ii) 26,324/INB > 0 | (ii) 43,842/INB > 0 |
| 9. Additional disutility owing to past MDD | ||||
| a. Base case: Yes | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: No | b. 3,751/INB > 0 | b. 16,892/INB > 0 | b. 26,399/INB > 0 | b. 44,256/INB > 0 |
| 10. Utility associated with CBT treatment | ||||
| a. Base case: 0.85 | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: 0.765 | b. 6,489/INB > 0 | b. 29,211/INB > 0 | b. 41,226/INB > 0 | b. 69,113/INB < 0 |
| 11. Number of CBT sessions (N) | ||||
| a. Base case: N = 14 | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) N = 6 | (i) 781/INB > 0 | (i) 8,360/INB > 0 | (i) 13,167/INB > 0 | (i) 23,392/INB > 0 |
| (ii) N = 20 | (ii) 7,539/INB > 0 | (ii) 27,659/INB > 0 | (ii) 42,648/INB > 0 | (ii) 69,761/INB < 0 |
| 12. Costs of physician-provided CBT | ||||
| a. Base case: Psychiatrist | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 25,914/INB > 0 |
| b. Scenario: GP | b. 3,175/INB > 0 | b. 18,690/INB > 0 | b. 25,914/INB > 0 | b. 21,806/INB > 0 |
| 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. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) $130,000/year, 17% benefits | (i) 2,675/INB > 0 | (i) No change | (i) 21,296/INB > 0 | (i) No change |
| (ii) $110,000/year, 30% benefits | (ii) 3,129/INB > 0 | (ii) No change | (ii) 23,083/INB > 0 | (ii) No change |
| (iii) $110,000/year, 17% benefits | (iii) 2,139/INB > 0 | (iii) No change | (iii) 18,812/INB > 0 | (iii) No change |
| 14. Costs of CBT, 2 providers | ||||
| a. Base case: Psychiatrist or highest paid nonphysician | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 25,914/INB > 0 |
| b. Scenario: GP or lowest paid nonphysician | b. 2,133/INB > 0 | b. 18,690/INB > 0 | b. 18,812/INB > 0 | b. 21,806/INB > 0 |
| 15. Direct medical costs | ||||
| a. Base case: All treatment costs | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: CBT treatment costs | b. 16,763/INB > 0 | b. 29,778/INB > 0 | b. 39,095/INB > 0 | b. 56,624/INB < 0 |
| 16. Costs of complex depression | ||||
| a. Base case: Responders | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: Nonresponders | b. Cost-saving/INB > 0 | b. 12,485/INB > 0 | b. 21,629/INB > 0 | b. 39,158/INB > 0 |
| 17. Costs of follow-up | ||||
| a. Base case: 100%, regular visits | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: Reduction of follow-up visits and costs by | b. | b. | b. | b. |
| (i) 25% | (i) 1,825/INB > 0 | (i) 14,840/INB > 0 | (i) 24,282/INB > 0 | (i) 41,812/INB > 0 |
| (ii) 50% | (ii) Cost-saving/INB > 0 | (ii) 12,950/INB > 0 | (ii) 22,651/INB > 0 | (ii) 40,180/INB > 0 |
| (iii) 75% | (iii) Cost-saving/INB > 0 | (iii) 11,060/INB > 0 | (iii) 21,019/INB > 0 | (iii) 38,547/INB > 0 |
| 18. Discount rate | ||||
| a. Base case: 1.5% | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenario: 5% | b. 4,058/INB > 0 | b. 17,154/INB > 0 | b. 26,323/INB > 0 | b. 43,910/INB > 0 |
| 19. Time horizon | ||||
| a. Base case: 5 years | a. 3,175/INB > 0 | a. 16,729/INB > 0 | a. 25,914/INB > 0 | a. 43,443/INB > 0 |
| b. Scenarios: | b. | b. | b. | b. |
| (i) 1 yearc | (i) 16,278/INB > 0 | (i) 30,555/INB > 0 | (i) 34,069/INB > 0 | (i) 50,129/INB < 0 |
| (ii) 2 years | (ii) 9,979/INB > 0 | (ii) 23,885/INB > 0 | (ii) 31,872/INB > 0 | (ii) 49,431/INB > 0 |
| (iii) 10 years | (iii) Cost-saving/INB > 0 | (iii) 6,177/INB > 0 | (iii) 11,789/INB > 0 | (iii) 24,896/INB > 0 |
| (iv) 20 years | (iv) Cost-saving/INB > 0 | (iv) Cost-saving/INB > 0 | (iv) Cost-saving/INB > 0 | (iv) 7,673/INB > 0 |
| (v) Lifetime | (v) Cost-saving/INB > 0 | (v) Cost-saving/INB > 0 | (v) Cost-saving/INB > 0 | (v) Cost-saving/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 cost-effective.
c
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).