Over the past three decades, the U.S. health care system has put an emphasis on well-visits – annual appointments with a primary care physician to help detect any medical problems early.  The idea makes perfect sense:  If a doctor can identify a medical condition in the early stages, the patient can begin treatment sooner and prevent the disease from progressing.

But this turns out to be a great example of how new evidence can contradict a widely-accepted practice.

A systematic review published this month by the Cochrane Collaboration  – one of our favorite data libraries – found that regular health checks-ups have no effect on a patient’s risk of developing cardiovascular disease, cancer or of dying. In other words, well visits do not decrease your risk of dying, heart disease or cancer.

The review included 14 longitudinal, randomized controlled trials. Each study included a group of adults  who were offered regular health checks and a control group of adults who were not. A total of 182,880 people participated in the studies.

The health checks did have some effects. Two of the trials identified greater numbers of patients with high blood pressure, high cholesterol and chronic diseases, but these trials still did not show an increased incidence of heart disease or death in the control group.

The authors did offer several caveats: Most of the trials were conducted decades ago, when the risk factors and treatments for chronic medical conditions were different than they are today. The authors also noted that primary care physicians are likely to identify chronic problems when a patient comes in for another issue, or complains of a symptom.

What’s the take-home message here?  As policy makers continue to debate the best ways to reform the U.S. health care system, they need to take into account all of the evidence on our current medical practices.