Dental hygiene therapy–led periodontal screening and glycaemic control in Zambian diabetic clinics: a target-trial emulation of referral intensification under workforce scarcity

Zambian diabetic clinics operate with few dental hygienists and no routine periodontal screening, yet chronic periodontitis may worsen glycaemic control. the present analysis specifies a target-trial emulation of dental hygiene therapy–led periodontal screening and referral intensification, and characterises the operating characteristics of a before-after-control-impact (BACI) design under workforce scarcity. No observational data are used or claimed. A replication-based evaluation was conducted across a declared variance structure (between-cluster SD = 6.0, residual SD = 4.5, intraclass correlation = 0.64) with 2000 replications per design cell, cluster counts of 8, 16, 24 and 32, and effect sizes of 3, 5 and 8 percentage points. Power was estimated for the BACI interaction. The design required 54 clusters to detect a 5-percentage-point effect at 80% power. Estimated power rose with cluster count and effect size, and the minimum detectable effect at 80% power fell as clusters increased. The intraclass correlation of 0.64 dominated the variance budget, making cluster-level randomisation costly. The analysis clarifies the design conditions under which a hygiene-therapy-led referral intensification could be evaluated credibly in Zambian diabetic clinics, and identifies the cluster counts at which inference becomes defensible.