Anticholinergic Polypharmacy in Medicare Not Common but Still Problematic, Study Says

A recent study examining the prevalence of anticholinergic polypharmacy among fee-for-service (FFS) Medicare beneficiaries with overactive bladder (OAB) found that it was mostly uncommon, but when it did happen, it was associated with worse outcomes and higher spending.

Prevalence was higher in women and in residents of nursing homes, according to the authors, writing in Drugs & Aging.

The retrospective cohort study examined claims data from 2006 to 2017. Anticholinergic polypharmacy was assessed by a health plan performance measure called “Polypharmacy: Use of Multiple Anticholinergic Medications in Older Adults” (Poly-ACH) that was created by the Pharmacy Quality Alliance.

Poly-ACH aims to identify coprescribing of strong anticholinergic medications in older adults because of an associated risk of cognitive decline, reduction of physical abilities, and greater difficulty performing activities of daily living.

About three-quarters of those on Medicare with OAB use at least 1 antimuscarinic drug, which belong to the class of oral anticholinergic medications. Given the risk of adverse events, they have been flagged as medications to avoid in certain circumstances, the researchers said.

However, given the lack of data on prevalence and economic consequences of anticholinergic burden, the authors said their study had 2 objectives: to characterize trends in the annual frequency of anticholinergic polypharmacy as measured by the Poly-ACH, and to examine the associations between positive Poly-ACH status and clinical and economic outcomes.

Poly-ACH was defined as concurrent use of 2 or more anticholinergics, each with 2 or more prescription claims on different dates of service for 30 or more cumulative days. The anticholinergic medications were listed in the 2019 American Geriatrics Society Beers Criteria. The presence of OAB was determined by 1 or more inpatient or outpatient facility claims or at least 2 claims filed by health care providers on separate dates with an OAB diagnosis code.

Researchers also included age category, female sex, region, and nursing home use category as covariates. Logistic regression was used to analyze trends, and panel regression modeling was used to analyze associations between Poly-ACH status and outcomes.

In total, 226,712 patients contributed 940,201 person-years of follow-up after an OAB diagnosis. The share of patients meeting the Poly-ACH definition was 3.3% in 2006, declining to 1.7% in 2017.

Having 1 year or more of positive Poly-ACH status in the 3 years prior was associated with higher rates of all negative outcomes:

• Falls: risk ratio (RR), 1.26; absolute difference of 1.0 percentage points; 95% CI, 0.07-1.30; P < .001
• Fractures: RR, 1.14; absolute difference of 0.4 percentage points; 95% CI, 0.20-0.70; P = .001
• Altered mental status: RR, 1.31; absolute difference of 0.8 percentage points; 95% CI, 0.50-0.10; P < .001

Women and nursing home residents had higher risks of anticholinergic polypharmacy; there were no statistically significant difference by age or region.

For spending outcomes, having 1 year of positive Poly-ACH was linked with $1163 in additional health care costs, $1169 higher at 2 years, and $964 at 3 years.

The authors said it is possible that the numbers of adults with OAB and polypharmacy reported in the study are underestimated.

"While the current study was not designed to determine causality, the findings nonetheless contribute evidence to an association between exposure to multiple anticholinergics and negative long-term consequences, which should be explored further," the researchers wrote.

Reference

Cambell NL, Hines L, Epstein AJ, Walker D, Lockefeer A, Sjiozawa A. A 12-year retrospective study of the prevalence of anticholinergic polypharmacy and associated outcomes among Medicare patients with overactive bladder in the USA. Drugs Aging. Published November 8, 2021. doi:10.1007/s40266-021-00901-2