Hong D, Tandan VR, Goldsmith CH, Simunovic M, Evidence-Based Surgery Working Group. Users’ guide to the surgical literature: how to use an article reporting population-based volume-outcome relationships in surgery. Can J Surg 2002;45(2):109-15.


Relman has defined the current period in North American health care as the “era of assessment and accountability” (EAA). In this era there is a close examination of the actions of health care institutions during the course of patient treatments and the actual patient outcomes that result. In the past, most attention centred on medical efficacy or the development of improved treatments through vehicles such as randomized clinical trials. While recognizing the continued importance of such efforts, the EAA also focuses on effectiveness or what atually happens when treatments are delivered to patients in the real world. A population-based volume-outcomes study is one tool that can be used to gain understanding of the effectiveness of therapies in large groups of patients.

Such studies use large databases and retrospective analyses to explore the relationship between treatment volume of procedures provided by hospitals and patient outcomes.

Most published volume-outcome studies show improved patient outcomes when treatment occurs in higher-volume centres. Such findings often prompt researchers and policymakers to recommend regionalization of the examined procedure into larger-volume hospitals. There are already reports of regionalization of care occurring for certain surgical procedures such as coronary artery bypass surgery, organ transplantation and pancreatic surgery, likely partly due to volume-outcome studies. But like any form of research, poorly designed and reported volume-outcome studies are of little benefit and may even be misleading. Given their potential influence on clinical care, resource allocation and policy decisions, it is imperative that these studies be methodologically sound.

Under what circumstances should you allow the results and conclusions made in a volume-outcomes report to influence your decision-making?

We provide in this article a framework of 3 questions to be considered when critically appraising such studies: Are the results of the study valid? What are the results? And will the results help me care for my patient? The issues are presented primarily for a surgical audience and can be applied to any study using large databases to make inferences about surgical care.

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