The -174G/C Interleukin-6 Gene Promoter Polymorphism as a Genetic Marker of Differences in Therapeutic Response to Methotrexate and Leflunomide in Rheumatoid Arthritis

Table 1

Comparison of selected characteristics of patients receiving methotrexate (MTX) versus leflunomide (LEF).

	MTX or LEF	MTX	LEF
Sociodemographic characteristics
Females, n (%)	93 (97)	53 (96)	40 (98)	1.00
Age (yr), mean ± standard deviation				0.06
Disease characteristics
Disease duration (yr), mean ± SD				0.05
HAQ-Di score at baseline, mean ± SD				0.33
DAS-28 score at baseline, mean ± SD				0.73
Rheumatoid Factor (RF) (IU/mL), mean ± SD				0.70
Erythrocyte Sedimentation Rate (ESR) (mm/h), mean ± SD				0.48
Interleukin-6 (IL-6) at baseline, (pg/mL) mean ± SD				0.40
Glucocorticoid dose (mg), mean ± SD				0.88
Patients achieving response
At 3 months, n (%)	14 (6.8)	7 (12.7)	7 (17.1)	0.38
At 6 months, n (%)	12 (8.0)	7 (12.7)	5 (12.2)	0.38
Genetic characteristics
Genotype GG, n (%)	54 (56)	33 (60)	21 (51)	0.58
Genotype GC, n (%)	31 (32)	17 (31)	14 (34)
Genotype CC, n (%)	11 (12)	5 (9)	6 (15)

RA: rheumatoid arthritis; IL-6: interleukin-6; MTX: methotrexate; LEF: leflunomide; HAQ-Di: Health Assessment Questionnaire-Disability index; DAS-28: modified Disease Activity Score (28 joints).
Qualitative variables were expressed in frequencies (%); quantitative variables were expressed in means ± standard deviations (SD). Comparisons between differences in proportions were performed with the chi-square test (or Fisher exact test if applicable). Comparisons between differences in means were performed with independent samples Student's t-tests. values were obtained comparing MTX versus LEF. Response was defined as the patient achieving, at 3 or at 6 months, low disease activity or remission (DAS28, <3.2).