Treating elderly patients with current clinical practice guidelines might have negative effects since the guidelines generally address single disorders and this population usually has several diseases, according to a new study.

They likely offer “little guidance to clinicians caring for older patients with several chronic diseases,” said the report published in the Journal of the American Medical Association. Dr. Cynthia M. Boyd of Johns Hopkins University’s Center on Aging and Health, was the lead investigator of the study.

In 1999, 48% of Medicare recipients 65 or older had at least three chronic health disorders, such as high blood pressure, chronic heart failure, diabetes and osteoporosis, according to the report. Also that year, about 21% of Medicare beneficiaries had five or more chronic medical conditions.