ABSTRACT
OBJECTIVE: To evaluate the association between weight loss and rheumatoid arthritis (RA) disease activity. METHODS: We conducted a retrospective cohort study of RA patients seen at routine clinic visits at an academic medical center, 2012-2015. We included patients who had ≥2 clinical disease activity index (CDAI) measures. We identified visits during follow-up where the maximum and minimum weights occurred and defined weight change and CDAI change as the differences of these measures at these visits. We defined disease activity improvement as CDAI decrease of ≥5 and clinically relevant weight loss as ≥5 kg. We performed logistic regression analyses to establish the association between improved disease activity and weight loss and baseline BMI category (≥25 kg/m2 or <25 kg/m2). We built linear regression models to investigate the association between continuous weight loss and CDAI change among patients who were overweight/obese at baseline and who lost weight during follow-up. RESULTS: We analyzed data from 174 RA patients with a median follow-up of 1.9 years (IQR 1.3-2.4); 117 (67%) were overweight/obese at baseline, and 53 (31%) lost ≥5 kg during follow-up. Patients who were overweight/obese and lost ≥5 kg had three-fold increased odds of disease activity improvement compared to those who did not (OR 3.03, 95%CI 1.18-7.83). Among those who were overweight/obese at baseline, each kilogram weight loss was associated with CDAI improvement of 1.15 (95%CI 0.42-1.88). Our study was limited by using clinical data from a single center without fixed intervals for assessments. CONCLUSION: Clinically relevant weight loss (≥5 kg) was associated with improved RA disease activity in the routine clinical setting. Further studies are needed for replication and to evaluate the effect of prospective weight loss interventions on RA disease activity.
ABSTRACT
OBJECTIVE: To investigate whether weight change during the early rheumatoid arthritis (RA) period is associated with subsequent mortality and to evaluate whether there is an RA-specific effect. METHODS: We identified patients with incident RA during the Nurses' Health Study (NHS; 1976-2016) and created a comparison cohort by matching each RA patient with up to 10 non-RA comparators by age and calendar year of the RA diagnosis (index date). To capture weight change around the early RA period ("peri-RA/index"), we used weight measurements collected 2-4 years before and 2-4 years after the index date. We used Cox regression analysis to estimate hazard ratios (HRs) for mortality according to peri-RA/index weight change categories, separately in each cohort and in the combined cohorts, evaluating for an RA-specific effect. RESULTS: Among 121,701 women in the NHS, 902 patients with incident RA were identified and matched to 7,884 non-RA comparators. In the RA cohort, 371 deaths (41.1%) occurred during a mean follow-up of 17.0 years after the early RA period, and 2,303 deaths (29.2%) occurred in the comparison cohort during a mean follow-up of 18.4 years. Weight loss of >30 pounds during the peri-RA period had a hazard ratio (HR) for mortality of 2.78 (95% confidence interval [95% CI] 1.58-4.89) compared to stable weight; results in the comparison cohort were similar (HR 2.16, 95% CI 1.61-2.88). A weight gain of >30 pounds had no association with mortality in patients with RA (HR 1.45, 95% CI 0.69-3.07) or comparators (HR 1.19, 95% CI 0.89-1.59). For mortality, there was no statistically significant interaction between RA/comparator status and weight change category (P = 0.68). CONCLUSION: Severe weight loss during the early RA period was associated with an increased subsequent mortality risk for women with and those without RA. These results extend prior observations by including non-RA comparators and finding no protective association between weight gain and mortality, providing evidence against an RA-specific obesity paradox for mortality.
