Dental Hygiene Therapy-Led Hypertension Screening in Cape Town Periodontal Clinics: A Stepped-Wedge Evaluation of Referral Completion and Cardiovascular Care Cascade Retention

Hypertension is the leading modifiable risk factor for cardiovascular disease in South Africa, yet a substantial proportion of adults remain undiagnosed and untreated. Periodontal clinics offer repeated contact with patients who carry a high burden of cardiometabolic risk, and dental hygienists are well placed to conduct opportunistic blood pressure screening. The primary outcomes were referral completion, defined as attendance at a designated primary care facility within 90 days of referral, and retention in the cardiovascular care cascade, defined as initiation of antihypertensive therapy and attendance at a follow-up visit within six months. A total of 1,842 patients were screened over the 12-month study period, of whom 612 (33.2%) had a raised blood pressure reading and were referred. Referral completion was achieved in 287 of 612 referred patients (46.9%; 95% CI 42.9–50.9). Cascade retention was achieved in 198 of 287 patients who completed referral (69.0%; 95% CI 63.6–74.4). The stepped-wedge design permitted estimation of the effect of the intervention on referral completion, with an adjusted odds ratio of 2.14 (95% CI 1.52–3.01; p < 0.001) for clinics in the intervention phase compared with the control phase. The findings suggest that dental hygiene therapy-led screening can meaningfully improve referral completion and cascade retention, but that the effect is attenuated by patient-level and health-system barriers that require parallel intervention.