Polypharmacy meets polyherbacy: pharmaceutical, over-the-counter, and natural health product use among Canadian adults.

Objectives: Natural health products (NHP) are increasingly being used to supplement prescription medications (PM) and over-the-counter (OTC) products. The objective of this study was to examine patterns of overall health product use and how these patterns are associated with social and health factors.

Methods: We used direct health measures data from the Canada Health Measures Survey (CHMS) Cycle 1.0 (2007/2009) to examine recent product use among adults aged 18-79 years (n=3,721). Latent class analyses were used to detect use (propensity) and intensity of use among users of all three product types. Associations between social and health covariates and product patterns were examined using linear and multinomial logit regression procedures.

Results: Three latent classes of health product use were identified. The largest (43%) was characterized by a high probability of PM and NHP but not OTC use. Class two (37%), in contrast, had a low probability of using any of the three health products. Class three (20%) had a high probability of PM and OTC but not NHP use. Age, gender, immigrant status, household size, co-morbidity, perceived health status, and having a regular doctor were associated with these patterns of use. Analyses of intensity of product use among users revealed seven distinct classes; these were differentiated by age, household size, co-morbidity and weight (BMI status).

Conclusion: If defining polypharmacy or polyherbacy is based simply on number of health products used, then for Canadians under age 80 neither practice appeared to be widespread. More work needs to be done to define the "poly" in polypharmacy and polyherbacy. This will inform the conversation on appropriate product use, particularly given that about one half of Canadians used medications and NHPs concurrently.