Review: Polypharmacy Significantly Linked With Malnutrition in Older Adults

It is still unknown whether the relationship between polypharmacy and malnutrition is bidirectional and authors could not determine causation.

Findings of a systematic review published in Clinical Nutrition revealed a statistically significant association between polypharmacy and malnutrition among older individuals without frailty.

Broadly, polypharmacy is defined as the simultaneous taking of numerous medications, although the exact number of drugs that constitutes polypharmacy incidence varies. The phenomenon has substantially increased over the past 2 decades, according to authors, and is especially prevalent in older individuals due to this population’s altered pharmacokinetics and decreased renal and hepatic drug clearance.

“Older people with polypharmacy take an average of 5 to 9 drugs prescribed for various reasons,” researchers explained, with the most common being for diabetes, hypertension, and sleep disturbances, among others.

Previous research has suggested a link between polypharmacy and malnutrition among adults due in part to side effects and patients’ higher intake of fluids when on the medications. However, the magnitude of the association has yet to be studied.

To carry out the systematic review, investigators searched databases for relevant literature published between January 2000 and September 2020.

All included studies (n = 7) were published in English or Dutch, while those on either frailty, sarcopenia, or cancer were excluded from the final sample, as these factors could serve as potential confounders.

In the current study, polypharmacy was defined as taking 5 or more drugs on a daily basis. “Malnutrition is usually defined as involuntary weight loss within a certain time frame and/or a low [body mass index]. A Mini Nutritional Assessment (MNA) score of ≤23.5 and Mini Nutritional Status Short Form (MNA-SF) score of ≤11 were also considered to indicate an increased risk of malnutrition,” authors said.

A total of 3368 participants were included in the 7 studies. Of the included studies, 2 defined polypharmacy as use of 5 or more drugs, and 2 as use of 6 or more drugs. Two more studies used a mean and standard deviation to correspond with the minimum of 5 drugs and the last study distinguished polypharmacy (5 or more drugs) from excessive polypharmacy (10 or more drugs).

Analyses revealed “all studies showed a statistically significant association between (the risk) of becoming malnourished and polypharmacy regardless the instrument or criterion used to define risk of malnutrition.”

Five studies measured additional risk factors associated with malnutrition apart from polypharmacy. Two found women had lower malnutrition scores than men, with main determinants including poor self-rated health for women, and overweight or obesity and depressive symptomatology for men. One other study found more comorbidities were linked with malnutrition.

Despite the statistically significant association between polypharmacy and malnutrition seen in each included study, no conclusions on causality could be drawn due to their designs, researchers cautioned. It also remains unclear which exact number of drugs increases the risk of malnutrition or whether differences between drugs exist.

“Malnutrition is not a causal factor for developing disease, yet malnourished patients are more prone to adverse events which require medication,” authors explained, adding “interactions between food and drugs can lead to either decreased bioavailability of a drug, which is prone to treatment failure, or increased bioavailability, which increases the risk of side effects and even toxicity.”

More research is needed to better understand if the association is bidirectional in that polypharmacy increases the risk of being malnourished or being malnourished leads to polypharmacy.

Regardless, authors point to increased communication between health care professionals as a potential solution to the problem.

“Although the insufficient quality of the reviewed studies makes it difficult to reach firm conclusions, more attention should be given to the nutritional status of older people with polypharmacy and at polypharmacy itself,” they concluded.

“Prevention and timely evaluation of polypharmacy, deprescribing, and monitoring of malnutrition, may lead to a reduced risk of malnutrition in older people.”


Kok WE, Haverkort EB, Algra YA, et al. The association between polypharmacy and malnutrition (risk) in older people: a systematic review. Clin Nutr. Published online March 11, 2022. doi:10.1016/j.clnesp.2022.03.007

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