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December 19, 2019/Functional Medicine/Research

Study Compares Two Models of Care for Chronic Disease

A first-of-its-kind study


Physicians who manage chronic disease are often working to counter their patients’ unhealthy lifestyle choices. It is a constant struggle physicians in many specialties know all too well.


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So, what can be done to reverse these unsustainable high costs of chronic disease? And how can medicine help these patients move toward making better choices?

A recently published study in the Journal of the American Medical Association Network Open demonstrates that the functional medicine model of care is associated with beneficial and sustainable improvements in health-related quality of life (HRQoL).

This fall, results of the first retrospective cohort study of the functional medicine model, conducted at Cleveland Clinic, found that functional medicine was associated with improvements in patient-reported HRQoL. This two-year study included 7,252 patients – 5,657 patients seen in primary care at a family health center and 1,595 patients treated in Cleveland Clinic’s Center for Functional Medicine.

“This was a first-of-its-kind study looking at the impact of functional medicine on patients’ health-related quality of life,” says Michelle Beidelschies, PhD, Director of Research and Education for the Cleveland Clinic Center for Functional Medicine and the lead author of the study. “Functional medicine is a system-based approach to chronic disease that, until now, has primarily been supported by anecdotal evidence and case reports. We know that further research is required, but this is a real start and a real look at how this model can help patients with chronic illness.”



The study was done using the NIH-validated questionnaire PROMIS® – the Patient-Reported Outcomes Measurement Information System, which measures a patients’ global physical and mental health by looking at factors like fatigue, physical function, pain, gastrointestinal issues and emotional well-being over time.

Study patients were aged 18 and older visiting the Cleveland Clinic Center for Functional Medicine or a Cleveland Clinic Family Health Center (for primary care) between April 1, 2015 and March 1, 2017. At 6 months, approximately 31% of patients seen by the Center for Functional Medicine improved their PROMIS global physical health scores by 5 points or more, which is a clinically significant change that has a noticeable impact on daily life. This was compared to 22% of primary care patients who improved their scores by 5 points or more.

At 12 months, patients seen by the Center for Functional Medicine showed improvement similar to that observed at 6 months, but these were not significant when compared with the improvements seen in primary care patients. The researchers noted the patients seen in the primary care setting center had a higher prevalence of diabetes and hypertension, higher mean baseline PROMIS scores and a higher median income.

Evaluating continuous changes over time

To examine this further, researchers evaluated continuous changes over time in PROMIS global physical health in a smaller group of patients seen by the Center for Functional Medicine at both 6 and 12 months and demonstrated improvements in PROMIS global physical health that were significantly larger compared to patients seen in a primary care setting.


“We believe that reasons for the improvements in health-related quality of life shown in the functional medicine patients include differences in the functional medicine model itself, the types of patients seeking functional medicine, and treatment adherence or belief in the model of care,” says Dr. Beidelschies. “And we will conduct future prospective studies to examine the functional medicine model of care and long-term outcomes.”

She adds that functional medicine looks at the body as a whole and focuses on the root causes of disease, not isolated symptoms. “It is based on the evidence that lifestyle factors – such as nutrition, sleep, exercise, stress levels, relationships and genetics – which are major contributors to chronic disease,” she says.

In 2014, Cleveland Clinic became the first academic medical center to open a Center for Functional Medicine. The Center requires that all new patients see a registered dietitian and health coach, in addition to a provider, as part of their initial visit, which typically lasts about 60 to 75 minutes. Patients also have the option to meet with a behavioral health therapist as part of any visit.

Since Cleveland Clinic’s Center for Functional Medicine opened its doors more than five years ago, staff has been preparing and conducting research to develop a body of empirical evidence about the efficacy of functional medicine practices.

The Cleveland Clinic research team on this study included Michelle Beidelschies, PhD, and Marilyn Alejandro-Rodriguez, BSAS, of Cleveland Clinic Center for Functional Medicine; Xinge Ji, MS, and Brittany Lapin, PhD, of Quantitative Health Sciences; Patrick Hanaway, MD, Institute for Functional Medicine, and Michael B. Rothberg, MD, MPH, of Cleveland Clinic Community Care.


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