Adjusted* mean incremental costs, incremental QALYs and incremental cost-effectiveness ratio over 24 months between tCBT versus usual care
| Analysis | Mean costs, (95% CI) | Mean QALYs, (95% CI) | Incremental mean costs, £ (95% CI)† | Incremental mean QALYs (95% CI) | ICER (£/QALY) | ||
| tCBT | Usual care | tCBT | Usual care | ||||
| Imputed dataset/ITT analysis (NHS perspective)‡ | 3094.68 (1775.65 to 9074.15) | 3052.38 (1735.77 to 8567.24) | 1.254 (1.238 to 1.270) | 1.231 (1.215 to 1.245) | 42.30 (−451.19 to 597.90) | 0.023 (0.007 to 0.039) | 1828 |
| SA: complete cases (NHS perspective)§ | 2684.53 (1817.69 to 5221.86) | 2454.67 (1645.66 to 4769.87) | 1.444 (1.415 to 1.471) | 1.420 (1.392 to 1.447) | 229.86 (−228.74 to 734.09) | 0.024 (−0.005 to 0.053) | 9608 |
| SA: imputed dataset (NHS+private care perspective) | 4239.22 (2135.82 to 15 332.80) | 4149.10 (2110.98 to 14 039.06) | 1.253 (1.238 to 1.270) | 1.231 (1.215 to 1.247) | 90.12 (−475.79 to 772.98) | 0.022 (0.007 to 0.039) | 4022 |
| SA: imputed dataset using actual trial expenses (NHS perspective)¶ | 3128.61 (1809.54 to 9164.04) | 3027.54 (1734.31 to 8587.83) | 1.254 (1.238 to 1.270) | 1.231 (1.215 to 1.245) | 101.07 (−373.14 to 641.98) | 0.023 (0.007 to 0.039) | 4367 |
| SA: imputed dataset using the cost of a complete tCBT course (NHS perspective)** | 3314.57 (1966.93 to 9059.99) | 2960.98 (1729.67 to 7781.19) | 1.254 (1.238 to 1.270) | 1.231 (1.215 to 1.245) | 353.59 (−80.46 to 1238.07) | 0.023 (0.007 to 0.039) | 15 280 |
| SA: imputed dataset using ICECAP (NHS perspective)†† | 4659.66 (1764.56 to 10 400.07) | 4787.56 (1815.05 to 10 632.20) | 1.288 (1.278 to 1.297) | 1.275 (1.266 to 1.284) | −127.90 (−603.19 to 545.33) | 0.013 (0.003 to 0.023)‡‡ | NA |
*Adjusted for baseline differences (age, gender, number of risk factors present, employment status, centre, baseline EQ-5D health utility score and baseline cost).
†Bootstrapped non-parametric 95% CI (2.5th/97.5th centile). Generalised linear model with γ distribution and log-link function to estimate incremental costs and generalised linear model with Poisson distribution and power 0.5 link function to estimate incremental QALYs/years of full capacity. Discounted at 3.5% per year.
‡Imputed dataset is the ITT analysis. Missing values were imputed to account for all participants included in the ITT analysis.
§593 complete cases were included (tCBT, n=297 and usual care, n=326). Complete cases are those with no missing data on cost and health utility at each time point.
¶Included the actual trial expenses per tCBT participant, £301. This was estimated using the lump-sum trial expenses incurred by therapists, including therapists’ training and tCBT delivery.
**Included the cost of a complete tCBT course per participant, £443. Time spent by therapist, training and supervision were included. The total time spent by the therapist was estimated by assuming that all tCBT participants attended a complete tCBT course consisting of nine sessions.
††Adjusted for baseline differences (age, gender, number of risk factors present, employment status, centre, baseline ICECAP value and baseline cost).
‡‡Incremental years of full capability.
EQ-5D, EuroQol Questionnaire-five dimensions; ICECAP, ICEpop CAPability measure for Adults; ICER, incremental cost-effectiveness ratio; ITT, intention to treat; NA, not applicable; NHS, National Health Service; QALYs, quality-adjusted life-years; SA, sensitivity analysis; tCBT, telephone-delivered cognitive–behavioural therapy.