Hyperglycemia is a greater-than-normal concentration of glucose in the blood, which is a hallmark of diabetes. In Type 1 diabetes, the immune system mistakenly attacks the beta cells of the pancreas and prevents them from producing enough insulin to meet the body’s needs, and hyperglycemia occurs. In Type 2 diabetes, the body becomes resistant to the effects of insulin; glucose can no longer be metabolized properly for energy, and it remains in the bloodstream.
Some research suggests people with rheumatoid arthritis (RA) or osteoarthritis (OA) may be particularly susceptible to either form of diabetes. Type 1 diabetes and RA are both autoimmune diseases, some of which tend to occur in the same individuals. Studies show that people with Type 1 diabetes tend to have high blood levels of C-reactive protein (CRP), IL-6, and TNF-alpha—all markers for RA. Further, etanercept, which is used to treat RA, has been shown to lower blood glucose levels and increase insulin production in children with newly diagnosed Type 1 diabetes.
Research also suggests that systemic inflammation (as from RA) predisposes people to insulin resistance and Type 2 diabetes. The development of Type 2 diabetes is predicted by elevated levels of CRP and IL-6. Furthermore, certain RA drugs may improve insulin sensitivity. Conversely, excess weight and obesity—risk factors for Type 2 diabetes—increase the risk of RA in women, probably by promoting systemic inflammation. Type 2 diabetes and OA also tend to occur in the same individuals, typically people who are overweight or obese.