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Elderly patients at risk of discontinuing medications for chronic conditions following surgery


A new study from the Institute for Clinical Evaluative Sciences (ICES) shows that elderly patients have an increased risk of discontinuing medications that they need to take regularly, following surgical procedures in hospital.

“Many older adults have a high burden of chronic illness, use several prescription drugs annually, and often receive care from multiple providers in numerous care settings. As such, they may be at high risk for discontinuing these medications during transitions from hospital care to community care,” said ICES adjunct scientist, Dr. Chaim Bell.

“However, little is known about why these medications may not be resumed following surgical procedures. Errors of omission can place seniors at risk for preventable adverse events.”

In order to examine this issue further, investigators tracked over 233,000 Ontarians, 66 years of age and older, who continuously used the blood thinner warfarin, statins, or beta-blocker eye drops for one or more years between April 1, 1997 and September 30, 2002. Patients taking warfarin are usually required to stop the drug prior to surgery because of an increased bleeding risk. In contrast, statins and eye drops do not have to be stopped prior to surgery.

Those who had an overnight hospitalization for elective surgeries were compared with two groups – one group that had ambulatory or outpatient procedures, and one group that had no procedures – in order to examine drug discontinuation within six months following hospital discharge.

The results showed that patients prescribed warfarin were more than twice as likely to discontinue the drug after an overnight hospitalization for elective surgery, and more than one and a half times more likely to discontinue the drug after an ambulatory procedure, compared to those who had no procedures. Having a procedure did not affect the risk of discontinuing either statins or beta-blocker eye drops.

“Our findings call attention to the need for improved practices to reduce the risk of preventable adverse events, such as discontinuing medications for chronic illnesses, that can occur during patients’ transitions between healthcare settings,” said Dr. Bell.

“These sorts of initiatives could include the development of electronic medical records and medication reconciliation programs on admission and on discharge, or models of care that facilitate communication and coordination between hospital and community-based physicians.”

The study, “Potentially unintended discontinuation of long-term medication use after elective surgical procedures”, is in the December 11, 2006 issue of the Archives of Internal Medicine.

Author affiliations: ICES (Drs. Bell, Bierman, Li, Mamdani, and Urbach); Departments of Medicine (Drs. Bell and Bierman), Health Policy, Management and Evaluation (Drs. Bell, Bierman and Urbach), and Family and Community Medicine (Dr. Bajcar), University of Toronto; Faculties of Pharmacy (Drs. Bajcar and Mamdani), and Nursing (Dr. Bierman), University of Toronto; Cancer Care Ontario (Dr. Urbach); Department of Surgery, University Health Network (Dr. Urbach); Department of Medicine, St. Michael’s Hospital (Drs. Bell and Bierman).

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.


  • Julie Dowdie
  • Media Relations Officer, ICES
  • (416) 480-4780 or cell (416) 432-8143

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