Primary Care Utilization and Prehospital Emergency Demand Among Patients with Multimorbidity in Spain

<b>Background/Objectives:</b> Patients with multimorbidity frequently rely on emergency services when continuity of care is weak. Strengthening communication between emergency and primary care can prevent unnecessary hospitalizations, yet this relationship remains underexplored. The aim of this study was to analyze the relationship between primary health care utilization in patients with multimorbidity and their demand for prehospital emergency services. <b>Methods:</b> An observational, longitudinal, analytical, and retrospective study was conducted in Málaga (Spain) between 2013 and 2017. Adults (>18 years) with multimorbidity who requested prehospital emergency care services at home were included; those with cancer, rare diseases, severe mental disorders, or incomplete electronic records were excluded. Variables encompassed sociodemographic, clinical, and behavioral characteristics, comorbidities, functional status, polypharmacy, resource type, and outcomes (on-site resolution or hospital referral). Primary health care visits before and after prehospital emergency use were extracted from electronic records. Descriptive, bivariate, and multivariate analyses were performed. <b>Results:</b> Among 532 patients, prior primary health care attendance predicted subsequent utilization (β = 0.57; <i>p</i> < 0.001), along with caregiver availability (β = 0.12; <i>p</i> = 0.001) and prehospital emergency services hyper-demand (β = 0.08; <i>p</i> = 0.022). Super-utilizers were younger, had ≥4 comorbidities, polypharmacy, prior family medicine visits, home oxygen therapy, and lower substance or alcohol use. <b>Conclusions:</b> In multimorbid adults, prehospital emergencies demand is influenced by factors beyond severity, including comorbidities, polypharmacy, the use of home medical devices, caregiver availability, and primary health care utilization patterns. Strengthening coordination between prehospital emergencies and primary health care, promoting patient-caregiver education, and implementing early notification pathways may improve care continuity and reduce avoidable emergencies.