LONDON – Tobacco use and excess weight can make it harder to achieve sustained remission in the treatment of early rheumatoid arthritis, according to findings from more than 1,000 patients in the Canadian Early Arthritis Cohort (CATCH) multicenter, prospective study.
Aggressive treatment that starts soon after diagnosis of rheumatoid arthritis (RA) is important for the absence of disease activity, which is the hallmark of sustained remission. But the reality is a success rate of less than 50% in the first 3 years with physical deterioration continuing thereafter. “Excess weight and smoking are two risk factors for developing RA. We were interested in seeing if they might also affect how well people responded to treatment,” said Susan Bartlett, Ph.D., a clinical psychologist at McGill University in Montreal.
At the annual European Congress of Rheumatology, Dr. Bartlett and colleagues reported on a cohort of 1,008 early RA patients who were enrolled in the Canadian Early Arthritis Cohort (CATCH) multicenter, prospective study and followed from around the time of diagnosis through the first 3 years of treatment to estimate the time it took until they achieved sustained remission, defined as having a 28-joint Disease Activity Score less than 2.6 for two consecutive visits.
Mean age of the patients (72% female, 81% white) was early 50s. Overall, 30% of females and 47% of males were overweight, one-third of both genders were obese, and 15%-20% smoked. Treatment at entry included methotrexate in mono- or combination therapy in about three-quarters of the patients, with steroids used in about half and biologics used sparingly.
The proportion of patients in sustained remission was 38% at 3 years, with a median time to remission of 11.3 months. “That finding wasn’t surprising because that is generally what is found in most studies of early RA. However, when we looked more closely at who was and wasn’t achieving remission, we found that people who smoked and those who were overweight or obese were much less likely than their nonsmoking, normal-weight peers to be in sustained remission,” Dr. Bartlett said in a pre-congress interview.
After adjustment for factors that could affect response to treatment – including age, race, disability status, pain, and early medications used – smoking (P = .046) and excess weight (P = .003) were associated with a poorer likelihood of achieving sustained remission. While more men than women were overweight or obese, the effects of weight and smoking appeared to be more problematic for women (P = .02).
An average nonsmoking male with a healthy body mass index (BMI; 25 kg/m2 or less) had about a 41% probability of achieving sustained remission within 3 years, compared with 15% for an obese male smoker. A nonsmoking female with a healthy BMI had a 27% probability of achieving sustained remission within 3 years, compared with 10% for an obese female smoker. Probabilities of sustained remission were also lower for overweight men and women, Dr. Bartlett reported.
Smoking and obesity have already been linked with an increased likelihood of developing RA, which in turn increases the risk of cardiovascular disease and premature death. The latest data suggest that both smoking and extra weight – including overweight and obese as defined by BMI – may also independently influence the success of treatment. “Our data suggest that if you have RA, it’s important to take the medications that your doctor has prescribed. If you smoke, you need to stop. And if you’re carrying extra weight, not only is that placing a greater demand on already vulnerable joints, it may also be making your RA treatment less effective,” Dr. Bartlett said.
These lifestyle modifications can be challenging for some people with RA, she said in the interview. Clinicians can help by considering lifestyle behaviors that lead to chronic diseases and poorer outcomes in addition to their more traditional view of diagnosis and treatment, she said, adding that patients and clinicians should know that even a small amount of weight loss can improve health and may improve response to therapy.
Well controlled clinical trials will be needed to better understand the benefits of weight control and smoking cessation on response to RA treatment. Also, why women who smoke and are overweight are at more of a disadvantage than their male counterparts is unknown. “As we begin putting these pieces together, we may learn valuable information that helps us to better control and ultimately cure RA,” said Dr. Bartlett.
The researchers had no conflicts of interest to declare.