National clinical guidelines and treatment centralization do not guarantee consistency in healthcare delivery

As clinical practice variation has been problematized as a symptom of suboptimal care and inefficient resource spending, consistency in the delivery of healthcare is a recurring policy goal. We examine a case where the introduction of a new treatment is most likely to provide consistency in healthcare delivery because it was introduced with a national clinical practice guideline representing consensus about best clinical practice among leading clinicians, and because care delivery was highly centralized to few high-volume treatment units. Despite the consensus on best clinical practice and care centralization, this study shows pronounced regional variation in patient outcomes and treatment costs that increased over time. Using a mixed-methods design, we find that the lack of consistency in care was largely unrelated to patient-specific characteristics, but seemed to reflect structural differences in the regional organization and financing of healthcare delivery. We conclude that the value of clinical practice guidelines is undermined when structural barriers limit the ability of clinicians and clinical managers to scale up treatment, and that some degree of decentralization may be a tool to maintain treatment intensity when the treatment effect is dependent on a high treatment intensity.