Table 3.
Three step hierarchical model predicting depression at Q1 follow-up
| Step 1 (Baseline data) | Step 2 (Passive Fitbit data) | Step 3 (DD mood data) | ||||
|---|---|---|---|---|---|---|
| z-score | AOR (95% CI) | z-score | AOR (95% CI) | z-score | AOR (95% CI) | |
|
| ||||||
| Pre SI | 2.08* | 1.84 (1.03, 3.28) | 2.07* | 1.84 (1.03, 3.30) | 1.34 | 1.53 (0.82, 2.86) |
| Sex | 2.01* | 1.28 (1.01, 1.64) | 1.97* | 1.29 (1.00, 1.66) | 1.53 | 1.23 (0.94, 1.60) |
| Pre PHQ-9 | 13.41*** | 1.33 (1.28, 1.39) | 13.44*** | 1.33 (1.28, 1.39) | 10.99*** | 1.28 (1.22, 1.34) |
| Sleep Mean | --- | −2.03* | 0.89 (0.79, 0.99) | −1.95 | 0.89 (0.79, 1.00) | |
| Sleep Variability | --- | 1.90 | 1.21 (0.99, 1.47) | 0.99 | 1.11 (0.90, 1.36) | |
| Steps Mean | --- | −0.57 | 0.98 (0.93, 1.04) | −0.28 | 0.98 (0.93, 1.05) | |
| Steps Variability | --- | −1.58 | 0.90 (0.80, 1.02) | −1.50 | 0.91 (0.79, 1.03) | |
| Mood Mean | --- | --- | −8.60*** | 0.57 (0.50, 0.65) | ||
| Mood Variability | --- | --- | 4.07*** | 1.79 (1.35, 2.38) | ||
| Model summary | ||||||
| Overall χ2 | χ2 (3) = 267.7, p <.001 | χ2 (7) = 281.2, p <.001 | χ2 (9) = 421.3, p <.001 | |||
| Step Δ | --- | χ2 (4) = 13.5, p = .009 | χ2 (2) = 140.1, p < .001 | |||
| Nagelkerke R2 | .187 | .196 | .285 | |||
| Overall AUC | .738 | .751 | .799 | |||
| BIC | 1824.3 | 1841.6 | 1717.0 | |||
Note.
*
p <.05
**
p <.01
***
p < .001. Depression as an outcome was indicated by a score of 10 or higher on the PHQ-9. Sleep variables were scaled to one hour, step variables were scaled to 1000 steps. DD = daily diary. Pre = Pre-internship. Q1 = Quarter 1 follow-up assessment. SI = Suicidal Ideation. PHQ-9 = Patient Health Questionnaire-9 score. AUC = Area Under the Curve. BIC = Bayesian Information Criterion.