Table 2.
Analyses of primary outcome (log-transformed PHQ-9 scores at 6 weeks)
|
Sertraline |
Placebo |
Adjusted proportional difference*(95% CI) | p value | |||
|---|---|---|---|---|---|---|
| n | Mean (SD) | n | Mean (SD) | |||
| Model 1† | 266 | 7·98 (5·63) | 284 | 8·76 (5·86) | 0·95 (0·85–1·07) | 0·41 |
| Model 2‡ | 266 | 7·98 (5·63) | 284 | 8·76 (5·86) | 0·94 (0·84–1·05) | 0·30 |
| Model 3§ | 266 | 7·98 (5·63) | 284 | 8·76 (5·86) | 0·95 (0·85–1·05) | 0·31 |
| Model 4¶ | 266 | 7·98 (5·63) | 282 | 8·81 (5·85) | 0·94 (0·85–1·05) | 0·28 |
| Model 5‖ | 324 | 8·25 (5·81) | 329 | 8·88 (5·87) | 0·96 (0·86–1·08) | 0·50 |
| Model 6** | 324 | 8·25 (5·81) | 329 | 8·88 (5·87) | 0·95 (0·85–1·07) | 0·39 |
Means (SDs) are for non-log-transformed PHQ-9 scores at 6 weeks. One person in the placebo group was missing the PHQ-9 score at baseline and one person in the sertraline group was missing the CIS-R depression score at baseline. These individuals were excluded from the regression model of the primary outcome at 6 weeks. PHQ-9=Patient Health Questionnaire, 9-item version. CIS-R=Clinical Interview Schedule—Revised.
All models use a log-transformed PHQ-9 score as the outcome. Adjusted proportional difference can be interpreted as the difference in scores between randomised groups expressed as a proportion (or percentage).
Primary analysis model: intention-to-treat analysis adjusted for baseline PHQ-9 and CIS-R depression scores and stratification variables (total CIS-R score in three categories, duration of depressive episode in two categories, and site; n=550).
Model 1 adjusted for variables showing imbalance at baseline (sex, ICD-10 depression diagnosis, marital status; n=550).
Model 1 adjusted for possible clustering effects using a random effect for general practices (n=550).
Model 1 adjusted for baseline variables associated with missing outcome data (age, ethnicity, marital status, financial difficulty, ICD-10 anxiety diagnosis, used antidepressants in the past, Beck Depression Inventory, second edition score, number of life events, Generalised Anxiety Disorder Assessment, 7-item version score; n=550).
Model 1 with missing data replaced by multiple imputation (n=653).
The imputed model (model 5) adjusted for variables showing imbalance at baseline (sex, ICD-10 depression diagnosis, marital status; n=653).