Ann Arbor, MI—Concerns are being raised about the high prevalence of polypharmacy among community-dwelling older dementia patients who are prescribed central nervous system (CNS)–active medications.

A cross-sectional analysis of about 1.2 million older adults with dementia, traditional Medicare, and prescription coverage in 2018 found that 13.9% were prescribed CNS–active polypharmacy. The report in JAMA defined polypharmacy in that case as overlapping prescription fills for three or more medications from the following drug classes: antidepressants, antipsychotics, antiepileptics, benzodiazepines, nonbenzodiazepine benzodiazepine receptor agonist hypnotics, and painkillers.

“In these patients, central nervous system (CNS)–active polypharmacy may increase the risk for impaired cognition, fall-related injury, and death,” write the University of Michigan–led authors.

The study team sought to determine the extent of CNS–active polypharmacy among community-dwelling older adults with dementia in the United States. Looking at patients with traditional Medicare coverage from 2015 to 2017, researchers estimated medication exposure using prescription fills between October 1, 2017, and December 31, 2018.

Participants had a median age of 83 years, and most, 65.2%, were female; 13.9% met the criterion for CNS–active polypharmacy with 32.1 million polypharmacy-days of exposure. Patients with CNS–active polypharmacy had a median age of 79.4 years, and 71.2% were female, according to the report.

Researchers report that, among those who met the criterion for CNS–active polypharmacy, the median number of polypharmacy-days was 193 (IQR, 88-315 polypharmacy-days). Furthermore, they write, of patients with CNS–active polypharmacy, 57.8% were exposed for longer than 180 days and 6.8% for 365 days. In addition, 29.4% were exposed to 5 or more medications and 5.2% were exposed to five or more medication classes.

The study determined that 92% of polypharmacy-days included an antidepressant, 47.1% included an antipsychotic, and 40.7% included a benzodiazepine. “The most common medication class combination included an antidepressant, an antiepileptic, and an antipsychotic (12.9% of polypharmacy-days),” the authors advise. “Gabapentin was the most common medication and was associated with 33.0% of polypharmacy-days.”

The authors suggest that the problem is likely to only become worse as more Americans are diagnosed with cognitive issues. “The number of persons with dementia in the U.S. is projected to grow to 50 million people by 2050, but the U.S. healthcare system is poorly equipped to deal with these patients and their complex medical and psychosocial needs,” they write. “Although memory impairment is the cardinal feature of dementia, behavioral and psychological symptoms (e.g., apathy, delusions, agitation) are common during all stages of illness and cause significant caregiver distress. Despite limited high-quality evidence of efficacy for pharmacological treatment, clinicians regularly prescribe psychotropic medications to community-dwelling persons with dementia in rates that far exceed use in the general older adult population.”

They add that the Beers Criteria from the American Geriatrics Society advise against such polypharmacy because of increased fall risk, adding that the medication combination also might cause impaired cognition, cardiac conduction abnormalities, respiratory suppression, and death in some cases.

“Given the high degree of comorbid medical illness and frailty among persons with dementia, associated risks from drug-drug and drug-disease interactions may be even greater than among older adults overall,” the researchers write. “In addition, persons with dementia may have difficulty articulating any adverse effects they are experiencing.”

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