Bipolar disorder more common in RA patients

The prevalence of bipolar disorder might be higher among rheumatoid arthritis patients than in the general population, Dr. Adir Farhi of Sheba Medical Center in Tel-Hashomer, Israel, and colleagues reported in the Journal of Affective Disorders.

In a case-control study of nearly 70,000 members of Clalit Health Services, the largest health maintenance organization in Israel, the prevalence of bipolar disorder was found to be greater in patients with rheumatoid arthritis (RA) than in case-matched controls (0.6% vs 0.4%; odds ratio, 1.34; 95% confidence interval, 1.02-1.76; P less than .05). The study included 11,782 patients with RA and 57,973 subjects matched by age and sex.

When stratified by age, the association was significant only in the two extreme age groups: age younger than 19 years (P less than .005) and age older than 75 years (P less than .005). However, in a logistic regression model, RA showed a trend for positive association with bipolar disorder that was not statistically significant, and age had a weak but statistically significant association. Smoking was positively and independently associated with bipolar disorder (multivariate OR, 1.66; 95% CI, 1.31-2.11; P less than .001).

“Our data implied that patients with RA have a greater prevalence of bipolar disorder than matched controls,” the authors wrote. But because the association may have been confounded by smoking status, “further research is warranted before making inferences about this association.”

Read the article in the Journal of Affective Disorders (doi: http://dx.doi.org/10/1016/j.jad.2015.09.058).

The prevalence of bipolar disorder might be higher among rheumatoid arthritis patients than in the general population, Dr. Adir Farhi of Sheba Medical Center in Tel-Hashomer, Israel, and colleagues reported in the Journal of Affective Disorders.

In a case-control study of nearly 70,000 members of Clalit Health Services, the largest health maintenance organization in Israel, the prevalence of bipolar disorder was found to be greater in patients with rheumatoid arthritis (RA) than in case-matched controls (0.6% vs 0.4%; odds ratio, 1.34; 95% confidence interval, 1.02-1.76; P less than .05). The study included 11,782 patients with RA and 57,973 subjects matched by age and sex.

When stratified by age, the association was significant only in the two extreme age groups: age younger than 19 years (P less than .005) and age older than 75 years (P less than .005). However, in a logistic regression model, RA showed a trend for positive association with bipolar disorder that was not statistically significant, and age had a weak but statistically significant association. Smoking was positively and independently associated with bipolar disorder (multivariate OR, 1.66; 95% CI, 1.31-2.11; P less than .001).

“Our data implied that patients with RA have a greater prevalence of bipolar disorder than matched controls,” the authors wrote. But because the association may have been confounded by smoking status, “further research is warranted before making inferences about this association.”

Read the article in the Journal of Affective Disorders (doi: http://dx.doi.org/10/1016/j.jad.2015.09.058).

The prevalence of bipolar disorder might be higher among rheumatoid arthritis patients than in the general population, Dr. Adir Farhi of Sheba Medical Center in Tel-Hashomer, Israel, and colleagues reported in the Journal of Affective Disorders.

In a case-control study of nearly 70,000 members of Clalit Health Services, the largest health maintenance organization in Israel, the prevalence of bipolar disorder was found to be greater in patients with rheumatoid arthritis (RA) than in case-matched controls (0.6% vs 0.4%; odds ratio, 1.34; 95% confidence interval, 1.02-1.76; P less than .05). The study included 11,782 patients with RA and 57,973 subjects matched by age and sex.

When stratified by age, the association was significant only in the two extreme age groups: age younger than 19 years (P less than .005) and age older than 75 years (P less than .005). However, in a logistic regression model, RA showed a trend for positive association with bipolar disorder that was not statistically significant, and age had a weak but statistically significant association. Smoking was positively and independently associated with bipolar disorder (multivariate OR, 1.66; 95% CI, 1.31-2.11; P less than .001).

“Our data implied that patients with RA have a greater prevalence of bipolar disorder than matched controls,” the authors wrote. But because the association may have been confounded by smoking status, “further research is warranted before making inferences about this association.”

Read the article in the Journal of Affective Disorders (doi: http://dx.doi.org/10/1016/j.jad.2015.09.058).