Dental hygiene therapy-led domiciliary oral care visits and aspiration pneumonia hospitalisation in Kenyan home-care cohorts: a target-trial emulation of visit frequency thresholds

Aspiration pneumonia is a leading cause of hospitalisation among older adults receiving home care, and poor oral hygiene is a modifiable risk factor. Whether the frequency of dental hygiene therapy-led domiciliary visits reduces hospitalisation, and at what threshold, remains unclear. The design is a before-after-control-impact (BACI) estimator evaluated through a replication-based power analysis under a declared variance structure (between-cluster SD = 6.0, residual SD = 4.5, intraclass correlation = 0.64). Power was estimated across 2000 design cells for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points.52 clusters are required to detect a 5-percentage-point effect at 80% power. The intraclass correlation of 0.64 substantially inflates sample size requirements. These findings inform the design of cluster-randomised trials and quasi-experimental evaluations of domiciliary oral care in similar settings.