About two years ago I wrote a three part series on the increased risk of cardiovascular disease (CVD), diabetes, and metabolic issues for people with rheumatoid arthritis. The articles are listed below.
Metabolic syndrome involves a set of interconnected risk factors that are related to cardiovascular disease and diabetes (see this excellent overview from the U.S. National Institutes of Health). All of these complex biochemical processes are connected and involve metabolism of food for energy, sugar processing, insulin, insulin resistance, fat/lipids including cholesterols and triglycerides, liver health, food types, excess weight, exercise, and systemic inflammatory responses. Whenever one of the interconnected systems gets out of normal parameters, a cascade of problems may occur which may impact cardiovascular health. In a study published in 2013, it was found that 18-49% of RA patients also had metabolic syndrome that was significantly higher than general populations. These researchers also found that RA patients with higher inflammatory blood markers and those who used corticosteroids were more likely to show signs of metabolic syndrome. Anti-inflammatory treatments for RA including DMARDS and many of the biologicals like anti-TNFs may impact the biochemical pathways involved in metabolism (see this recent study). Cardiovascular risk is one extra-articular manifestation of RA that can have serious and fatal consequences.
According to the U.S. National Institutes of Health,
“Insulin resistance is a condition in which the body produces insulin but does not use it effectively. When people have insulin resistance, glucose builds up in the blood instead of being absorbed by the cells, leading to type 2 diabetes or prediabetes.”
A review of research conducted by European rheumatologic researchers (Amaro, et al., 2011) connected insulin resistance to RA. They revealed that insulin resistance was more common in RA patients with higher inflammatory blood markers (c-reactive protein, ESR) and disease activity measured by the DAS28.
A recent study published in the journal Arthritis and Rheumatology focused on insulin resistance and RA. Giles, et al., 2015 stated that the connection between insulin resistance and RA is poorly understood. They examined almost 400 people, 200 RA patients and 200 non-RA patients. They measured variables associated with CVD and insulin resistance. They found that insulin resistance levels were much higher in the RA group and demographic factors did not play a role. Insulin resistance was higher in patients with positive rheumatoid factor (RF) tests for both genders and higher for women who use steroids. They concluded by arguing that while insulin resistance levels were higher in RA patients, it remains unclear how this impacts cardiovascular risks.
More research is needed into this critical area of extra-articular (outside the joint) affect of rheumatoid arthritis.