Dental hygiene therapy–delivered domiciliary oral care and aspiration pneumonia readmission in Kenyan nursing homes: a target-trial emulation of visit-frequency thresholds under caregiver turnover

Aspiration pneumonia readmission among nursing-home residents is a persistent clinical and policy concern, yet the optimal frequency of domiciliary oral care delivered by dental hygiene therapists remains undefined, particularly where caregiver turnover is high. Because no primary observational data were available, the study characterises the operating characteristics of a before-after-control-impact design under a declared variance structure. The design assumed a between-cluster standard deviation of 6.0, a residual standard deviation of 4.5, and an intraclass correlation of 0.64. 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 indicates that 52 clusters would be required to detect a 5-percentage-point effect at 80% power. Minimum detectable effect curves and power curves are presented to inform the design of future target-trial emulations in this setting. The framework offers a methodological contribution by specifying the design parameters and sample-size requirements necessary to evaluate visit-frequency thresholds under caregiver turnover, thereby enabling future empirical work to proceed with justified precision.