This learning activity examines the clinical progression from stable, single-system chronic disease to complex multimorbidity across the lifespan, drawing on current epidemiologic data, cardiometabolic clustering research, and professional screening guidelines (ADA, USPSTF) to help nurses recognize early signals of increasing disease complexity. It addresses age-specific risk stratification from pediatric transition planning through geriatric polypharmacy and frailty, evidence-based coordination strategies such as teach-back and structured handoffs, and the ethical imperative to individualize care for patients whose multimorbidity places them outside the evidence base of single-disease guidelines. The content is designed to strengthen nurses' ability to assess proactively, stratify risk appropriately, coordinate care across fragmented systems, and center clinical decision-making on patient goals and equity considerations.