RA is a chronic inflammatory disease that affects the joints, causing pain and disability. It can also affect internal organs. RA is more common in older people, but there is also a high prevalence in young adults, adolescents and even children, and it affects women more frequently than men. IBD is an umbrella term used to describe disorders that involve chronic inflammation of the digestive tract, such as Crohn's disease and ulcerative colitis.
IBD can be debilitating and sometimes lead to life-threatening complications. Type I diabetes is a serious, lifelong condition where blood glucose levels are too high because the body can't make insulin.
Results of the study demonstrate that the RA group reported significantly more cases of inflammatory bowel disease (1.9% vs. 0.5%, p<0.001) and type I diabetes (1.3% vs. 0.4%, p=0.01) versus controls.
"While it is common for patients to have both type I diabetes and rheumatoid arthritis, our results suggest that inflammatory bowel disease and type I diabetes may predispose to rheumatoid arthritis development, which merits further study," said Vanessa Kronzer, M.D., Mayo Clinic School of Graduate Medical Education, Minnesota, USA.
Although the number of comorbidities was the same between groups in the timeframe prior to RA diagnosis, in the time period after RA diagnosis there were significantly more comorbidities reported in the RA group versus controls (median 5.0 vs. 4.0, p<0.001).
In addition, between group differences were significant for several comorbidities. Interestingly, there were significantly more cases reported in the RA group for venous thromboembolism (VTE) (10% vs. 6%, p<0.001) and epilepsy (3% vs. 1%, p=0.003) versus controls, indicating that they may be novel comorbidities for patients with RA.
Heart attacks were more common in the RA group versus controls (3.8% vs. 1.2%, p<0.001) but high cholesterol was less common (11.4% vs. 16.4%, p=0.004). Cancer was not more common in either group, even among all cancer subtypes.
"These results are important because understanding the timeline of comorbidity development in patients with rheumatoid arthritis will inform our knowledge of the disease progression and help identify targets for improving outcomes," said Professor Hans Bijlsma, President, EULAR.
The study included 821 patients with RA from a biobank, each with a further three matched controls based on age, sex, and location of residence at the time of the biobank survey. The survey included the self-reported presence/absence and age of onset for 77 comorbidities. The mean age was 62 years, and 73% were female.