Study Highlights Use of PIMs in US Adults With Multimorbidity, Polypharmacy

A recent study examined the utilization and costs of potentially inappropriate medications (PIMs) used by older adults in the United States with multiple chronic conditions, a situation that can lead to higher health care costs and potential adverse events.

The researchers said that to their knowledge, it is the first study to specifically focus on the issue of polypharmacy, or the use of 5 or more medications, which is common in older adults with multiple health issues. The authors noted that polypharmacy is likely to rise as the US population ages. According to one study, 39% of US adults aged 65 or older used 5 or more medications.

Gaining more clarity on polypharmacy “could inform interventions and policy discussions on how to optimize pharmacotherapy in this population group,” the authors noted.

The study used linked Medicare claims and electronic health records from 7 Massachusetts facilities between 2007 and 2014, including 2 medical centers, 3 community hospitals, a rehabilitation center, and a psychiatric hospital. Records included demographics, inpatient and outpatient data, labs, prescribing and dispensing records, and other medical care. The Medicare claims included parts A, B, and D. Data included information about drugs dispensed and medical diagnoses.

Using the Chronic Condition Indicator (CCI) of the Agency for Healthcare Research and Quality and doing further analysis with International Classification of Diseases, Ninth Edition, codes, researchers came up with 77 categories of chronic conditions. Patients were considered multimorbid if they had diagnoses from 2 or more categories. Polypharmacy was defined as using prescription drugs from 5 or more pharmaceutical classes for 90 days or more.

PIMs were identified with the 2019 Beers criteria and the analysis considered dispensed medications, not prescribed ones. The study calculated the percentage of patients with 1 or more PIMs as well as the percentages of patients using different types of PIMs. Multivariable logistic regression was used to test the odds of taking 1 or more PIMs and mean costs spent on PIMs was calculated by dividing the costs spent on PIMs by the total medication cost.

Of all 569,969 patients in the database, between 61,500 and 103,153 met criteria for inclusion. Demographics and clinical characteristics did not change over the course of the study. The mean number of drugs was 7.2; the average age range was between 77.3 and 77.8. Body mass index ranged between 28.7 to 29.1.

Most the patients used 1 or more PIM (≥ 69%) and the differences did not change over the course of the study.

What did change, however, between the beginning and end of the time period was the mean number of chronic conditions, rising from 7.2 to 8.4, as well as certain chronic conditions. In addition, the majority of those affected were women, although the percentage fell from 65.2% in 2007 to 59.3% in 2014. Hispanic ethnicity was also linked with PIMs.

Gastrointestinal drugs (proton-pump inhibitors) and central nervous system drugs (such as benzodiazepines, antidepressants, antipsychotics) were the most commonly-used PIMs, and there was no difference by sex. However, men were more likely to use cardiovascular PIMs.

In patients using ≥1 PIM, >10% of medication costs were spent on PIMs. Between 11.0% and 12.8% of medication costs were spent on PIMs in women and between 11.0% and 12.2% in men between 2007 to 2014; the average amount spent on PIMs ranged from $392 to $719 for women and $395 to $759 for men.

The study did have a few limitations. Different tools are available to examine PIMs, and since this study used Beers criteria, the results may not be applicable to other research using other methods. In addition, while Beers is the most commonly used metric in the United States, the authors noted that “Beers criteria are criterion rather than judgment-based. Despite using diagnoses and clinical criteria to determine PIM use, some medications defined as potentially inappropriate may have been used as a last resort. In other cases, alternative to PIMs might have been more expensive.”

Other limitations include possible data misclassification; possible underestimated usage of PIMs as over-the-counter drugs were not included; and the fact that the patient population was from a large urban area, where patients may have access to more health care.

Screening for PIMs by pharmacists or primary care physicians should become a regular part of practice, the authors concluded, and deprescribing interventions should be considered.

Reference

Tabea Jungo K, Streit S, Lauffenburger JC. Utilization and spending on potentially inappropriate medications by us older adults with multiple chronic conditions using multiple medications. Arch Gerontol Geriatr. 2021;93:104326. doi:10.1016/j.archger.2020.104326