IBD, T1D may be risk factors for RA
Both inflammatory bowel disease (IBD) and type 1 diabetes (T1D) are highly prevalent among patients who eventually develop rheumatoid arthritis (RA), indicating that these two conditions are potential risk factors for RA, according to a study presented at EULAR 2019.
“While it is common for patients to have both T1D and RA, our results suggest that IBD and T1D may predispose to RA development,” said lead author Dr Vanessa Kronzer from Mayo Clinic School of Graduate Medical Education in Rochester, Minnesota, US.
The researchers conducted a case-control study involving 821 patients with RA who were matched with 2,455 controls (mean age 62 years, 73 percent female). Each RA case was matched to three controls based on age, sex, and location of residence at the time of the biobank survey. Prevalence of comorbidities among patients with RA and time association of comorbidity development relative to RA onset were evaluated. Presence or absence and age of onset of comorbidities were self-reported by the participants during the survey. [EULAR 2019, abstract OP0088]
Prior to diagnosis of RA, significantly more patients in the RA group had a higher prevalence of IBD (1.9 percent vs 0.5 percent; p<0.001) and T1D (1.3 percent vs 0.4 percent; p=0.01) compared with the non-RA group.
“The increased occurrence of IBD and T1D prior to RA suggests either a predisposition to RA development or a shared immunological defect, meriting further study,” said Kronzer.
Compared with the non-RA group, the RA group also showed a significantly higher prevalence of comorbidities, such as osteoarthritis (50 percent vs 38 percent; p<0.001), gastroesophageal reflux disease (38 percent vs 28 percent; p<0.001), cataracts (35 percent vs 29 percent; p=0.003), and sleep apnoea (20 percent vs 15 percent; p<0.001) at the time of the baseline survey.
After RA diagnosis, a significantly higher prevalence of venous thromboembolism (10 percent vs 6 percent; p<0.001) and epilepsy (3 percent vs 1 percent; p=0.003) was evident in patients with RA than those without.
Results also showed that patients with RA were more likely to develop myocardial infarction (3.8 percent vs 1.2 percent; p<0.001) than those without RA.
Hyperlipidaemia was significantly lower in the RA group than the non-RA group (11.4 percent vs 16.4 percent; p=0.004).
The incidence of cancer occurred at a rate of 31 percent in the RA group and 32 percent in the non-RA group. “[Of note,] RA was not associated with an increased risk of cancer,” said Kronzer.
“[However,] many comorbidities were associated with RA, including several potentially novel comorbidities such as COPD, epilepsy, and acid reflux,” said Kronzer.“These results are important because understanding the timeline of comorbidity development in patients with RA will inform our knowledge of the disease progression and help identify targets for improving outcomes,” said EULAR President, Professor Hans Bijlsma.