System weaknesses (e.g., resource availability, deficiencies in care coordination) threaten patient safety. This population-based cohort study including 4.7 million Danish adults who interacted with primary or hospital care in 2018, found that indicators of care fragmentation (e.g., higher numbers of involved clinicians, more transitions between providers) increased with patient morbidity level. The researchers found that higher levels of care fragmentation were associated with adverse outcomes, including potentially inappropriate prescribing and mortality.