Table 4.
Three step hierarchical model predicting suicidal ideation 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 | 7.16*** | 8.26 (4.64, 14.81) | 7.11*** | 8.22 (4.61, 14.77) | 6.46*** | 7.93 (4.24, 14.94) |
| Sex | −0.54 | 0.91 (0.66, 1.27) | −0.62 | 0.90 (0.64, 1.26) | −0.96 | 0.84 (0.59, 1.20) |
| Pre PHQ-9 | 6.80*** | 1.19 (1.13, 1.25) | 6.79*** | 1.19 (1.13, 1.25) | 4.16*** | 1.12 (1.06, 1.19) |
| Sleep Mean | --- | 0.10 | 1.01 (0.86, 1.21) | 0.32 | 1.03 (0.86, 1.25) | |
| Sleep Variability | --- | 0.49 | 1.07 (0.80, 1.42) | −0.25 | 0.96 (0.72, 1.28) | |
| Steps Mean | --- | −0.01 | 1.00 (0.93, 1.08) | 0.39 | 1.02 (0.94, 1.09) | |
| Steps Variability | --- | −0.53 | 0.96 (0.81, 1.13) | −0.46 | 0.96 (0.81, 1.14) | |
| Mood Mean | --- | --- | −7.41*** | 0.55 (0.47, 0.64) | ||
| Mood Variability | --- | --- | 2.27* | 1.53 (1.06, 2.20) | ||
| Model summary | ||||||
| Overall χ2 | χ2 (3) = 168.0, p <.001 | χ2 (7) = 168.7, p <.001 | χ2 (9) = 243.8, p <.001 | |||
| Step Δ | --- | χ2 (4) = 0.7, p = .953 | χ2 (2) = 84.9, p < .001 | |||
| Nagelkerke R2 | .168 | .168 | .249 | |||
| Overall AUC | .735 | .739 | .798 | |||
| BIC | 1125.0 | 1155.2 | 1085.7 | |||
Note.
*
p <.05
**
p <.01
***
p < .001. 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.