Long-term patterns of health services utilization after hospitalization for COPD. A nationwide registry-based study from Norway

Chronic obstructive pulmonary disease (COPD) is commonly regarded as an ambulatory care-sensitive condition (ACSC), for which targeted outpatient and primary care can improve patients' outcomes and reduce their risk of hospitalization. Yet little is known about how COPD patients' use of such services evolves in real-life settings. Using national health registry data from Norway (2008-2020), linked to demographic and socioeconomic registers, we explore how COPD patients' combined use of primary and specialist services evolves in the first four years after an acute respiratory hospital episode, and assess whether these patterns align with clinical guidelines and vary by sociodemographic characteristics. A two-stage clustering approach was employed to identify individuals with similar care trajectories. The 13,057 patients were first grouped by the number of respiratory hospital episodes after the index episode (0, 1-2, or 3+), then K-medoid clustering was performed within each group to identify similar patterns of respiratory-related outpatient and primary health service utilization. Four distinct care trajectories emerged within each group, with similar combination patterns: (1) predominantly GP services (most common), (2) GP and outpatient services, (3) GP, out-of-hours primary care and infrequent outpatient services, and (4) frequent physiotherapist, GP and outpatient services (rarest). Notably, groups 2 and 4 had higher income and education than groups 1 and 3, and many patients do not follow care trajectories according to current guidelines for COPD treatment. Understanding the mechanisms that explain these variations in health services use, and their implications for care quality and equity, is essential for improving COPD management in universal healthcare systems.