Abstract
{ "background": "Ghana's urban primary care networks (UPCNs) represent a major health system reform, yet robust evidence on their impact on clinical outcomes is lacking. Existing evaluations often rely on cross-sectional or descriptive designs, limiting causal inference about the effectiveness of these integrated service delivery models.", "purpose and objectives": "This protocol details a quasi-experimental study designed to evaluate the causal effect of UPCN enrolment on key clinical outcomes for hypertension and type 2 diabetes. The primary objective is to estimate the network's impact on medication adherence and systolic blood pressure control.", "methodology": "A controlled before-and-after study will be implemented across four urban districts. Intervention facilities (\(n=12)\) are matched with control facilities (\(n=12)\) on facility size and baseline performance. We will recruit a cohort of adult patients with hypertension or diabetes (estimated \(n=1\),440). The primary analysis will use a difference-in-differences approach with a linear mixed-effects model: $Y{it} = \\beta0 + \\beta1 (Timet \\times Treatmenti) + \\gamma X{it} + \\alphai + \\epsilon{it}$, where $Y_{it}$ is the outcome for patient $i$ at time $t$. Inference will be based on cluster-robust standard errors adjusted for facility-level clustering.", "findings": "As a protocol, no empirical findings are presented. The anticipated primary outcome is a quantifiable difference in the proportion of patients achieving controlled systolic blood pressure (<140 mmHg) between intervention and control groups at 12-month follow-up.", "conclusion": "This protocol provides a methodological framework for generating high-quality evidence on the clinical effectiveness of a pivotal health system intervention in an African urban context.", "recommendations": "Researchers evaluating complex health system interventions in similar settings should adopt rigorous quasi-experimental designs with matched controls and longitudinal data collection to strengthen causal claims.", "key words": "health systems research, quasi-experimental design, primary health care, difference-in