Background The increase of insulin resistance (IR) was signaled in rheumatoid arthritis (RA), but its prevalence in ankylosing spondylitis (AS) is not explored.The relationship between the inflammatory process, disease activity and demographic data have been poorly studied up till now.
Objectives The aim of the study was to assess the prevalence of IR and its relationships with markers of inflammation, disease activity and demographic parameters in patients (pts) with RA and AS.
Methods 102 patients [60 with RA, 42 with AS] were studied. Average age of patient was 52 [35; 65] in RA and 38,8 [20; 61] years in AS group. Mean BMI – 25,8 [17,6; 36,7] and 24,3 [17,9; 34,9], mean WHR 0,85 [0,66; 1,14], and 0,88 [0,68; 1,1] in RA and AS group.Mean duration of disease - 12,2 [1,0; 36] and 7,8 [1,0; 35] years, respectively. Mean DAS28 - 4,19 [1,41; 7,07], mean BASDAI - 4,01 [0,6; 10].The Homoeostasis Model Assessment (HOMA) and Insulin/Glucose index were used to measure insulin resistance and the Quantitative Insulin Sensitivity Check Index (QUICKI) and Matsuda index to measure insulin sensitivity. The inflammatory disease activity was assessed using measurements of ESR, hs-CRP, IL-6, IL-6sR, SAA.
Results The indices of IR were significantly higher in RA patients than in those in AS group. The mean values of HOMA-IR were 1,95±1,52 vs. 1,18±0,64 (p<0,01), and I/G 0,11±0,12 vs. 0,05±0,03 (p<0,001). The indices of insulin sensitivity were significantly lower in RA patients - mean QUICKI 0,36±0,03 vs. 0,38±0,03 (p<0,001), mean Matsuda 6,83±3,49 vs. 10,15±5,1 (p<0,001). All of these indices were significantly correlated with BMI and WHR in group RA and with BMI (with WHR only HOMA-IR and I/G) in group AS, however there was no significant difference in terms of WHR and BMI in both groups. In addition, HOMA-IR and QUICKI in group RA were correlated with hemoglobin (Hb) (r=0,33; r= -0,36, p<0,01) and uric acid levels (UA) (r=0,28; r= -0,30, p<0,05). Moreover, the negative correlation between IR and glucocorticoid (GCs) treatment (mean prednison dose 5,4 mg/d) in patients of RA for HOMA-IR and Matsuda index has been shown. There weren't any associations between the studied parameters and disease activity (DAS28, BASDAI),disease duration, age and acute phase parameters: ESR, hs-CRP,IL-6, IL-6 sR, SAA. Of these parameters hs-CRP and SAA showed a strong correlation with disease activity in RA patients (r=0,59; r=0,63, p<0,001) but not in those with AS.
Conclusions Insulin resistance occurs more frequently in patients with RA than AS. It was dependent on body weight indices in both cases, whereas not on disease activity as well as markers of inflammation. Acute phase parameters: hs-CRP and SAA strongly correlated with the disease activity in patients with RA.
Disclosure of Interest None declared