New York, Researchers have found that adults with rheumatoid arthritis had a lower risk of developing type 2 diabetes than other individuals, including those with other types of arthritis.

"We have examined the risk of incident type 2 diabetes mellitus among rheumatoid arthritis patients versus four different comparison cohorts," said the study authors from Harvard University in the US.

For the study, published in the journal Arthritis Care & Research, the research team compared adults with rheumatoid arthritis with four other groups - individuals from the general population without rheumatoid arthritis, individuals with hypertension, individuals with osteoarthritis, and individuals with psoriatic arthritis.

According to the researchers, a total of 449,327 people were included. During the median of 1.6 years of follow-up, the rate of type 2 diabetes development was lowest in the rheumatoid arthritis group (7.0 per 1,000 people per year) and highest (12.3 per 1,000 people per year) in the hypertension group.

After adjustments, rheumatoid arthritis was associated with a 24 per cent to 35 per cent lower risk of developing type 2 diabetes compared with the four other groups. In this large population-based cohort study, the findings showed that patients had a lower rate of incident type 2 diabetes compared to the general non-rheumatoid arthritis, hypertension, osteoarthritis, and psoriatic arthritis cohorts.

"While systemic inflammation in rheumatoid arthritis increases the risk of cardiovascular disease, our findings unexpectedly show that having rheumatoid arthritis itself does not confer an increased risk of type 2 diabetes compared with four different comparator groups," said senior author Seoyoung C. Kim.

"Since all rheumatoid arthritis patients included in our study were treated with at least one disease-modifying antirheumatic drug, our study is unable to test the association between no treatment or under-treatment for rheumatoid arthritis and risk of type 2 diabetes," Kim noted.