Go to content

Dementia patients with multiple physicians or in long-term care at risk of medication conflict


Many older patients who are prescribed cholinesterase inhibitors for dementia or Alzheimer’s disease are also taking anticholinergic drugs that can worsen their cognition, says a team of researchers from the Institute for Clinical Evaluative Sciences (ICES) and Women's College Hospital. The risk of this drug combination is especially high when the patient sees multiple physicians or lives in a long-term care facility.

"Although prescribing anticholinergic drug therapy to persons with dementia is generally considered inappropriate, these therapies are often prescribed in clinical practice," says Dr. Paula Rochon, lead researcher on the study who is a senior core researcher at ICES and vice-president of research at Women’s College Hospital. "Anticholinergic drug therapy prescribed together with cholinesterase inhibitor drug therapy is particularly concerning, since the cognitive benefits gained from one drug are undone by the other."

Anticholinergics are a class of drugs that block the action of the neurotransmitter acetylcholine in the brain. They are commonly prescribed to treat a wide range of illnesses including asthma, incontinence, intestinal cramps, muscle spasms, depression and sleep disorders.  Because of their frequent layering and multiple adverse effects including cognitive impairment, a tool called the Anticholinergic Risk Scale (ARS) has been developed to estimate the risk of adverse effects from anticholinergic medications using a range from zero (no risk) to three and up (high risk).

Published online this week in the Journal of the American Geriatrics Society, the study analyzes the anonymized records of older adults who had been newly dispensed cholinesterase inhibitor drugs, usually prescribed for dementia or Alzheimer’s disease. The researchers divided the population into two groups: one group was composed of 79,067 community-dwelling patients (at a mean age of 81), and the other group consisted of 12,113 long-term care residents (at a mean age of 84).

In the community-dwelling group:

  • Patients saw an average of eight unique physicians in the prior year.
  • Most (63 per cent) of the community-dwelling patients prescribed cholinesterase inhibitors received no anticholinergic drugs in the prior year, as recommended. However, 16 per cent had an ARS score of one, nine per cent had an ARS score of two, and 12 per cent had an ARS score of three or more.
  • The odds of high anticholinergic drug burden increased by 24 per cent for every five additional physicians providing care within the prior year (adjusted odds ratio, 1.24; 95 per cent confidence interval, 1.21-1.26).
  • Female sex, low-income status, previous hospitalization and higher comorbidity score were also associated with higher ARS risk scores.

In the long-term care group:

  • Patients saw an average of 10 unique physicians in the prior year.
  • Compared to the community-dwelling group, high anticholinergic drug risk was twice as likely for long-term care residents, with 29 per cent having ARS scores of three or more.
  • Despite guidelines, 61 per cent of persons in LTC were taking at least one anticholinergic drug at the time of initiating cholinesterase inhibitor drug therapy.
  • Unlike the community-dwelling group, the risk of high anticholinergic burden for LTC residents did not increase as the number of physicians grew but remained high overall.

“We know from previous studies that having multiple prescribers is linked to an increase in polypharmacy, potential drug interactions, and adverse events,” says Christina Reppas-Rindlisbacher, the study’s lead researcher and an MD candidate at the University of Toronto. “Older adults with dementia and multiple comorbid conditions are particularly vulnerable to this risk because they often receive care from multiple physicians, who may not be communicating well with each other. Given the potential risks of anticholinergic drug use, we suggest that improving communication amongst physicians and checking ARS risk scores prior to prescribing any new drug therapy are important strategies to ensure that these vulnerable patients receive the best possible care.”

“Anticholinergic drug burden in persons with dementia taking a cholinesterase inhibitor: the effect of multiple physicians” was published this week in the Journal of the American Geriatrics Society.

Author block:  Christina E. Reppas-Rindlisbacher, Hadas D. Fischer, Kinwah Fung, Sudeep S. Gill, Dallas Seitz, Cara Tannenbaum, Peter C. Austin and Paula A. Rochon.

The Institute for Clinical Evaluative Sciences (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. For the latest ICES news, follow us on Twitter: @ICESOntario

About Women’s College Hospital – For more than 100 years Women’s College Hospital (WCH) has been developing revolutionary advances in healthcare. Today, WCH is a world leader in the health of women and Canada’s leading, academic ambulatory hospital. A champion of equitable access, WCH advocates for the health of all women from diverse cultures and backgrounds and ensures their needs are reflected in the care they receive. It focuses on delivering innovative solutions that address Canada’s most pressing issues related to population health, patient experience and system costs. The WCH Institute for Health System Solutions and Virtual Care (WIHV) is developing new, scalable models of care that deliver improved outcomes for patients and sustainable solutions for the health system as a whole.

Women’s College Research Institute (WCRI) is tackling some of the greatest health challenges of our time. Its scientists are conducting global research that advances the health of women and improves healthcare options for all, and are then translating those discoveries to provide much-needed improvements in healthcare worldwide.
For more information about how WCH and WCRI are transforming patient care, visit www.womenscollegehospital.ca and www.womensresearch.ca


  • Kathleen Sandusky
  • Media Advisor, ICES
  • [email protected]
  • (o) 416-480-4780 or (c) 416-434-7763
  • Emily Hanft
  • Director, Communications & Marketing
  • Women’s College Hospital
  • 76 Grenville Street | Toronto, ON M5S 1B2
  • T: 416-323-6400 ext. 4054
  • [email protected]


Contributing ICES Scientists

Associated Sites

Read the Journal Article