Clin Rheumatol DOI 10.1007/s10067-013-2427-8
ORIGINAL ARTICLE
Lack association of body mass index with disease activity composites of rheumatoid arthritis in Korean population: cross-sectional observation Jung-Yoon Choe & Jisuk Bae & Hwajeong Lee & Sung-Hoon Park & Seong-Kyu Kim
Received: 29 May 2013 / Revised: 19 October 2013 / Accepted: 24 October 2013 # Clinical Rheumatology 2013
Abstract The debate regarding the influence of body mass index (BMI) on clinical disease activity in rheumatoid arthritis (RA) remains unsolved. This study investigates whether BMI is associated with disease activity composites and clinical parameters in Korean patients with RA. A total of 568 patients with RA were consecutively enrolled in this study. BMI and disease activity composites including the Disease Activity Score 28 (DAS28) and the Clinical/Simplified Disease Activity Index (CDAI/SDAI) were assessed. Statistical analyses were performed using Chi-square, one-way ANOVA, and multivariate regression analyses. Remission of RA disease activity was defined as ≤2.6 in a DAS28 score. The mean BMI was 22.3 kg/m2 (SD 3.1). About 60.6 % (n =344) of enrolled patients fell into the underweight and normal BMI categories. Swollen joint count was significantly different among the four BMI categories (p =0.038). Multivariate regression analysis showed a negative correlation of BMI and erythrocyte sediment rate (ESR) in all patients (β=−0.011, p =0.049) and also found that other disease activity indices were not found to be associated with BMI. In patients with remission, lower BMI was associated with higher physician global estimate (β=−0.446, p =0.030). The negative association between BMI and ESR in the non-remission group was noted (β = − 0.016, p = 0.019). This study revealed lack Electronic supplementary material The online version of this article (doi:10.1007/s10067-013-2427-8) contains supplementary material, which is available to authorized users. J.30 kg/m2. In the comparison of mean values and prevalence for BMI between RA patients and the general population, mean BMI values were found to be similar [25]. In addition, more than 60 % of RA patients had abnormal body composition including overweight or obesity status (i.e., BMI>25). Considering the application of RA-specific BMI cut-off points, the prevalence of overweight and obese BMI individuals may be increased compared to that using the classic WHO criteria [26]. However, classification proposed by the IOTF was applied in the present study, indicating overweight status as 23–25 kg/m2 and obesity at >25 kg/m2 [19], because the WHO criteria for overweight or obesity status might be inappropriate for the Asian population. The prevalence of overweight and obesity among RA patients in this study was estimated at approximately 20.4 % and 19.0 %, respectively. This data seems to be much lower compared to data from studies performed in Western populations. On the contrary, RA patients with normal and underweight BMI accounted for about 60.6 % of the study population. Regarding the analysis of prevalence of BMI categories from the general population in Korea, 38.6 % were normal (BMI
ORIGINAL ARTICLE
Lack association of body mass index with disease activity composites of rheumatoid arthritis in Korean population: cross-sectional observation Jung-Yoon Choe & Jisuk Bae & Hwajeong Lee & Sung-Hoon Park & Seong-Kyu Kim
Received: 29 May 2013 / Revised: 19 October 2013 / Accepted: 24 October 2013 # Clinical Rheumatology 2013
Abstract The debate regarding the influence of body mass index (BMI) on clinical disease activity in rheumatoid arthritis (RA) remains unsolved. This study investigates whether BMI is associated with disease activity composites and clinical parameters in Korean patients with RA. A total of 568 patients with RA were consecutively enrolled in this study. BMI and disease activity composites including the Disease Activity Score 28 (DAS28) and the Clinical/Simplified Disease Activity Index (CDAI/SDAI) were assessed. Statistical analyses were performed using Chi-square, one-way ANOVA, and multivariate regression analyses. Remission of RA disease activity was defined as ≤2.6 in a DAS28 score. The mean BMI was 22.3 kg/m2 (SD 3.1). About 60.6 % (n =344) of enrolled patients fell into the underweight and normal BMI categories. Swollen joint count was significantly different among the four BMI categories (p =0.038). Multivariate regression analysis showed a negative correlation of BMI and erythrocyte sediment rate (ESR) in all patients (β=−0.011, p =0.049) and also found that other disease activity indices were not found to be associated with BMI. In patients with remission, lower BMI was associated with higher physician global estimate (β=−0.446, p =0.030). The negative association between BMI and ESR in the non-remission group was noted (β = − 0.016, p = 0.019). This study revealed lack Electronic supplementary material The online version of this article (doi:10.1007/s10067-013-2427-8) contains supplementary material, which is available to authorized users. J.30 kg/m2. In the comparison of mean values and prevalence for BMI between RA patients and the general population, mean BMI values were found to be similar [25]. In addition, more than 60 % of RA patients had abnormal body composition including overweight or obesity status (i.e., BMI>25). Considering the application of RA-specific BMI cut-off points, the prevalence of overweight and obese BMI individuals may be increased compared to that using the classic WHO criteria [26]. However, classification proposed by the IOTF was applied in the present study, indicating overweight status as 23–25 kg/m2 and obesity at >25 kg/m2 [19], because the WHO criteria for overweight or obesity status might be inappropriate for the Asian population. The prevalence of overweight and obesity among RA patients in this study was estimated at approximately 20.4 % and 19.0 %, respectively. This data seems to be much lower compared to data from studies performed in Western populations. On the contrary, RA patients with normal and underweight BMI accounted for about 60.6 % of the study population. Regarding the analysis of prevalence of BMI categories from the general population in Korea, 38.6 % were normal (BMI
