Trauma Ward Mental Health Rehabilitation Discharge Planning Meeting Timing and Post-Traumatic Stress Disorder Aftercare Enrollment Among Nigerian Inpatients: A Target-Trial Emulation of Transition Coordination Windows

The timing of discharge planning meetings on trauma wards may influence whether inpatients with post-traumatic stress disorder (PTSD) enroll in aftercare, yet the coordination window that would make such an effect detectable has not been characterised. No observational data were used; the analysis characterised the operating characteristics of the BACI estimator under a declared variance structure with an intraclass correlation of 0.64, between-cluster standard deviation of 6.0 and residual standard deviation of 4.5. Power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The analysis identified that 56 clusters would be required to detect a 5 percentage point effect at 80% power. The results indicate that plausible ward-level designs in Nigerian trauma services are underpowered for small effects, and that target-trial emulation of transition coordination windows requires either cluster counts approaching 56 or effect sizes of at least 8 percentage points. Discharge planning timing research should be designed around detectable coordination windows rather than assumed small effects.