London, United Kingdom—Smoking and obesity reduce the likelihood of treatment success in patients with early rheumatoid arthritis (RA).1 The negative effects of smoking and obesity are present in both sexes, but were more robust in women according to the results of a study presented at the 2016 European League Against Rheumatism Annual Congress (EULAR 2016).
“We have great medications for the treatment of RA. Patients come in all the time asking what they can do,” explained Susan Bartlett, PhD, Associate Professor, Faculty of Medicine, Divisions of Clinical Epidemiology, Respiratory Epidemiology and Rheumatology, McGill University, Montreal, Canada, and lead author of the study. “This study adds to the evidence for the benefits of stopping smoking and losing weight and shows that it is particularly important if you want the RA medications to work well. We should be telling this to patients at the first visit after diagnosis.” Although sustained remission is an important treatment goal in early RA, <50% of patients achieve this goal within the first 3 years of treatment, and will continue to deteriorate.
The study was based on a cohort of 1008 patients with early RA enrolled in the multicenter, prospective Canadian Early Arthritis Cohort (CATCH) study. Patients were followed prospectively from the time of diagnosis through their first 3 years of treatment to estimate the time to sustained remission, defined as remission (Disease Activity Score 28, <2.6) at ≥2 consecutive visits to the rheumatology clinic. At baseline, mean age of patients in the study was 53 years; 72% of the participants were women, and 81% were white. Overall, 30% of women and 47% of men were overweight, 33% of both sexes were obese, and 15% to 20% were smokers. At entry, approximately 75% of patients were treated with methotrexate alone or as part of a combination therapy, roughly 50% received steroids, and 3% were treated with a biologic. At 3 years, 38% of patients had achieved sustained remission, with a median time to remission of 11.3 months.
“When we looked more closely at who was and was not achieving remission, we found that people who smoked and those who were overweight or obese were much less likely than their non-smoking or normal-weight peers to be in sustained remission,” Dr Bartlett stated.
Differences Between Sexes
Overall—and even though more men were overweight—men did better than women, with the effects of weight and smoking appearing to be significantly more difficult among women (P = .02). Looking at weight separately, obese people were 50% less likely to achieve remission than their normal-weight counterparts. Smoking also impacted treatment success. A significant 3-way interaction was observed for sex, weight, and smoking (P = .02).
A nonsmoking man with a healthy body mass index (BMI) would have a 41% probability of achieving sustained remission within 3 years, whereas the probability drops to 15% for an obese man who is a smoker. Among women, a nonsmoker with a healthy weight would have a 27% probability of achieving sustained remission within 3 years, compared with only 10% for a woman who smokes and is obese.
The mechanisms behind smoking cessation and weight loss are not well-established. There are data suggesting that adipose tissue activates inflammatory cytokines that can worsen RA.
BMI, Smoking, and Treatment Nonresponse
In support of the CATCH study, researchers behind a second abstract presented at EULAR 2016 found that BMI and smoking were significant predictors of nonresponse after 6 months of methotrexate treatment in 549 adult patients with RA.2 Odds ratios for nonresponse were as follows: BMI, 1.06 (P <.01); current smokers, 1.59 (P = .04).
“These factors that predict nonresponse are modifiable,” explained Suzanne Verstappen, MD, Arthritis Research UK Centre for Epidemiology, Centre for Musculoskeletal Research, Institute of Inflammation and Repair, The University of Manchester, United Kingdom, who coauthored the second study.
- Bartlett SJ, Schieir O, Schulman OE, et al. How much of a barrier is excess weight and smoking for achieving sustained remission in early RA? Results from the Canadian Early Arthritis Cohort. Presented at: 2016 European League Against Rheumatism Annual Congress; June 8-11, 2016; London, United Kingdom. https://b-com.mci-group.com/Abstract/Statistics/AbstractStatisticsViewPage.aspx?AbstractID=304435. Accessed June 10, 2016.
- Sergeant JC, Hyrich KL, Anderson J, et al. Prediction of non-response to methotrexate therapy in the Rheumatoid Arthritis Medication Study (RAMS). Presented at: 2016 European League Against Rheumatism Annual Congress; June 8-11, 2016; London, United Kingdom. https://b-com.mci-group.com/Abstract/Statistics/AbstractStatisticsViewPage.aspx?AbstractID=304312. Accessed June 10, 2016.