TABLE 3.
Poisson Regressions—Independent Effects of Intervention Group, Baseline Variable, and “Group-by-Baseline Variable” Interaction on Outcome (Completed Suicide)
| Independent Variables (Group and Gender) | p | RR (95% CI) ESPP/Preintervention Group | p | RR (95% CI) Female/Male | p | RR (95% CI) Group × Gender (Interaction) |
|---|---|---|---|---|---|---|
| Model 1 | ||||||
| Asymptotic model: with interaction term | 0.043a | 0.213 (0.048–0.953) | 0.290a | 0.381 (0.064 – 2.280) | 0.747a | 1.469 (0.143–15.143) |
| Asymptotic model: removing interaction term | 0.018a | 0.251 (0.079–0.792) | 0.206a | 0.476 (0.151 – 1.504) | ||
| Independent Variables (Group and Living Arrangement) | ESPP/Preintervention Group | Living Alone: Yes/No | Group × Living Alone (Interaction) | |||
| Model 2 | ||||||
| Asymptotic model: with interaction term | 0.016a | 0.199 (0.053–0.742) | 0.884a | 0.850 (0.095–7.605) | 0.258a | 4.858 (0.315–75.001) |
| Asymptotic model: removing interaction term | 0.044a | 0.297 (0.091–0.969) | 0.309a | 2.011 (0.524–7.721) | ||
| Independent Variables (Group and GDS Below Cutoff) | ESPP/Preintervention Group | GDS < 8: Yes/No | Group × GDS <8 (Interaction) | |||
| Model 3 | ||||||
| Asymptotic model: with interaction term | 0.390a | 0.475 (0.087–2.593) | 0.060a | 5.571 (0.931–33–343) | 0.208a | 0.223 (0.022–2.302) |
| Asymptotic model: removing interaction term | 0.013a | 0.225 (0.070–0.726) | 0.154a | 2.317 (0.731–7.346) | ||
| Independent Variables (Group and History of Suicide Attempt) | ESPP/Preintervention Group | History of Suicide Attempt: Yes/No | Group × History of Suicide Attempt (Interaction) | |||
| Model 4 | ||||||
| Asymptotic model: with interaction term | 0.012a | 0.187 (0.050–0.696) | 0.460a | 0.438 (0.049–3–914) | 0.352a | 3.670 (0.238–56.667) |
| Asymptotic model: removing interaction term | 0.023a | 0.259 (0.081–0832) | 0.887a | 0.908 (0.241–3–428) | ||
| Independent Variables (Group and ICD-10 Depressive Disorder) | ESPP/Preintervention Group | Current Diagnosis of Depressive Disorder (ICD-10): Yes/No | Group × Current Diagnosis of Depressive Disorder (ICD-10) (Interaction) | |||
| Model 5 | ||||||
| Asymptotic model: with interaction term | 0.055a | 0.174 (0.029–1.042) | 0.696a | 0.700 (0.117–4.189) | 0.552a | 2.028 (0.197–20.903) |
| Asymptotic model: removing interaction term | 0.027a | 0.267 (0.083–0.860) | 0.905a | 1.074 (0.333–3–460) | ||
| Independent Variables (Group and Index Attempt Requiring Hospitalization) | ESPP/Preintervention Group | Index Attempt Requiring Hospitalization: Yes/No | Group × Index Attempt Requiring Hospitalization (Interaction) | |||
| Model 6 | ||||||
| Asymptotic model: with interaction termb | — | — | — | — | — | — |
| Asymptotic model: removing interaction term | 0.029a | 0.278 (0.088–0.875) | 0.105a | 5.449 (0.703–42.245) | ||
Notes: RR: relative risk (e.g., RR of ESPP/preintervention group = risk for completed suicide when exposed to ESPP group relative to exposure to preintervention group); group: intervention group (ESPP versus preintervention group); CI: confidence interval.
a
p values are from Poisson regression with df = 1.
b
Relative risk and p value could not be calculated as Hessian matrix singularity was caused by parameter.