Abstract
BACKGROUND: The nurse-patient relationship is central to quality nursing care, yet its impact remains difficult to quantify. While existing models assess caring competencies from the perspective of nursing students and professionals, there is a lack of validated instruments incorporating direct patient feedback. OBJECTIVE: This study aimed to develop and validate the Nursing Interaction in Caring_Competence Assessment-Patient (NIC_CA-Patient) tool, a patient-centred instrument designed to measure caring interaction in nursing practice and establish a predictive model of its development from the patient's perspective. METHODS: A cross-sectional study was conducted in eight hospitals within the Andalusian Health Care System, involving 1060 patients admitted to internal medicine units. The NIC_CA-Patient tool was adapted from the Caring Nurse-Patient Interactions (CNPI) scale and validated through exploratory factor analysis (EFA) and partial least squares structural equation modelling (PLS-SEM). RESULTS: The final model identified three key dimensions-therapeutic relationship, problem management and adaptation-explaining 79% of the variance in patient-reported experiences. The predictive model demonstrated strong reliability (Cronbach's α = 0.97) and excellent model fit indices (SRMR = 0.03, AVE > 0.7). CONCLUSION: The NIC_CA-Patient tool provides a quantifiable and predictive measure of caring interaction from the patient's perspective. Its implementation in clinical practice and research can enhance patient-centred care by identifying relational factors that improve health outcomes and patient experience.