In the U.S., approximately 18% of adults report taking natural product dietary supplements, the most frequently used form of complementary and alternative medicine. Such supplements are commonly used to treat musculoskeletal conditions, with a higher prevalence of supplement use reported by adults with arthritis.
Past research describes the potential risk of drug interactions while taking supplements with prescribed medications. But specific drug interactions between supplements used by patients with rheumatoid arthritis (RA) and standard RA therapies are largely unknown. And 76% of the general adult population does not discuss their supplement use with their physicians, creating the potential for population-specific safety hazards going unrecognized. RA patients may be at a higher risk for supplement-related side effects due to the underlying nature of the disease and frequent use of complex pharmaceutical regimens, which include disease-modifying antirheumatic and biologic drugs.
To gain insight, Janel C. DeSalvo, MD, and colleagues from the University of Arizona, Tucson, conducted a scoping review of the current literature, examining the population-based patterns of natural product dietary supplement use for RA self-management. The researchers analyzed data from 23 studies published between 1980 and 2015 and conducted in 11 countries. The majority of studies had RA-specific populations or subgroups. The findings were published in the June 2019 issue of Arthritis Care & Research.
The Results
“Data from this scoping review identified a high prevalence of [natural product dietary supplements] use by RA populations worldwide,” write the authors in their discussion. “Similarly, because this review also confirms a frequent lack of disclosure of [supplement] use by patients with RA, (as has been shown for adults in the general population), our goal of identifying population-based patterns of specific product use for RA appears to be clinically relevant.”
According to the review, the overall prevalence of natural product dietary supplement use in RA patients was 47% worldwide and did not differ by geographic region. Approximately 47% of patients found these supplements effective. Patients cited decreased pain intensity, improved sleep, alleviation of symptoms, reduced swelling and improved activity levels as signs of effectiveness. The most common supplements included marine oils, glucosamine, vinegar and chondroitin. Thirteen percent of patients reported adverse side effects, which included gastrointestinal upset, swelling, increased pain, nausea and dermatologic manifestations.
On average, only 30% of patients told their physicians about their supplement use, representing a significant communication gap. Reasons cited for not reporting supplement use included the perception of safety and the absence of physician questions.