Model parameters for the decision tree and Markov model
| Mean | SE | Distribution | |
|---|---|---|---|
| Probabilities* | |||
| Within trial—likelihood of being depressed at follow-up: usual care | 0.72 | 0.030 | Triangular 0.72±20% |
| Within trial—likelihood of being depressed at follow-up: collaborative care | 0.57 | 0.039 | Triangular 0.57±20% |
| Markov transition: not depressed→depressed | 0.37 | − | Triangular 0.37±20% |
| Markov transition: remains depressed | 0.71 | − | Triangular 0.71±20% |
| Markov transition: depressed→dead | 0.02 | − | Triangular 0.02±20% |
| Markov transition: not depressed→dead† | 0 | − | − |
| Costs | |||
| Within trial: usual care | 1670 | 203 | γ |
| Within trial: collaborative care | 2140 | 264 | γ |
| Markov state: not depressed | 1516 | 257 | γ |
| Markov state: depressed | 1730 | 219 | γ |
| Markov state: dead | 0 | − | − |
| QALYs | |||
| Within trial: usual care | 0.169 | 0.006 | β |
| Within trial: collaborative care | 0.185 | 0.007 | β |
| Markov state: not depressed (usual care) | 0.196 | 0.008 | β |
| Markov state: depressed (usual care) | 0.158 | 0.007 | β |
| Parameters for sensitivity analyses‡ | |||
| Markov transition: not depressed→depressed (collaborative care) | 0.19 | − | Triangular 0.19±20% |
| Markov transition: remains depressed (collaborative care) | 0.56 | − | Triangular 0.56±20% |
| Markov state: not depressed (collaborative care) | 0.207 | 0.005 | β |
| Markov state: depressed (collaborative care) | 0.168 | 0.007 | β |
*Probabilities not stated in the table are the exhaustive compliment of reported probabilities for each model event.
†Background all-cause mortality assumed to be 0.
‡Primary analysis assumed equivalent probabilities/utilities (usual care) for both trial groups.
QALY, quality-adjusted life year.