Transforming GP practices into multiprofessional primary care centers: The role of nursing professionals (PRIMA) – study protocol for a multicenter non-randomized, controlled, parallel-group intervention study

Background Germany faces increasing challenges in primary care due to demographic change, workforce shortages, and the growing prevalence of chronic conditions. Integrating nursing professionals into primary care teams may improve continuity, comprehensiveness, and efficiency of care, but evidence for the German setting remains limited. The PRIMA project (DRKS00039104) implements a new care model that transforms general practices into multiprofessional primary care centers integrating specially trained nursing professionals. The objective is a productivity- and quality-oriented reorganization of care for patients with chronic diseases. The intervention targets patients with high-risk chronic diseases. Core elements include extended nursing services, subsidiary task allocation within the practice team, structured organizational development, and optional use of a medical triage software. Methods Effectiveness and health-economic outcomes are evaluated in a prospective, quasi-experimental, controlled study under real-world conditions. The intervention group includes patients from 20 participating practices; the control group is matched using routine claims data. The primary endpoint is the number of ambulatory care–sensitive emergency cases after 12 months, analyzed intention-to-treat. Secondary outcomes include healthcare utilization, mortality, continuity, and coordination of care. Statistical analyses will account for confounding and clustering at practice and patient level. The health economic evaluation will estimate incremental cost-effectiveness ratios based on ambulatory and total healthcare costs. A parallel process evaluation uses longitudinal mixed-methods. It comprises interviews, activity logs and focus groups, and surveys among patients, their relatives, practice teams and collaborators. Key aspects assessed include implementation facilitators and barriers, organizational development and interprofessional collaboration, nurse role development, and patient quality of life and treatment satisfaction. Discussion Findings are highly relevant for strengthening primary care in Germany and internationally, where multidisciplinary primary care centers are increasingly promoted. If successful, the intervention could reduce emergencies and improve patient outcomes, serving as a scalable model and informing policy and reimbursement strategies.