Polymorphism rs2073618 of the TNFRSF11B (OPG) Gene and Bone Mineral Density in Mexican Women with Rheumatoid Arthritis

Table 1

Comparison of selected patient characteristics between rheumatoid arthritis (RA) with low bone mineral density (BMD) versus RA with normal BMD and among subgroups of patients with RA with osteoporosis (OP), osteopenia, and normal BMD.

	Low BMD; ()	Normal BMD; ()		Osteoporosis; ()	Osteopenia; ()	Normal BMD; ()
Sociodemographic characteristics
Age (yr), mean ± SD	62 ± 9	54 ± 7	<0.0001	62 ± 8	61 ± 10	54 ± 7	<0.0001
BMI (kg/m^2), mean ± SD	27.5 ± 4.1	29.8 ± 4.3	0.002	26.9 ± 3.9	28.5 ± 4.1	29.8 ± 4.3	0.001
Disease characteristics
Disease duration (yr), mean ± SD	14 ± 10	13 ± 11	0.58	13 ± 10	14 ± 9	13 ± 10	0.75
DAS28, mean ± SD	3.5 ± 1.5	3.4 ± 1.4	0.58	3.7 ± 1.5	3.8 ± 1.5	3.4 ± 1.4	0.37
HAQ-Di score, mean ± SD	0.62 ± 0.60	0.38 ± 0.36	0.003	0.49 ± 0.52	0.60 ± 0.71	0.38 ± 0.36	0.11
ESR (mm/hr), mean ± SD	25 ± 10	23 ± 13	0.39	28 ± 12	24 ± 10	24 ± 13	0.18
CRP (mg/mL), mean ± SD	18.6 ± 32.6	12.6 ± 11.8	0.29	21.9 ± 39.6	13.0 ± 14.0	12.6 ± 11.8	0.22
RF (UI/mL), mean ± SD	192 ± 533	74 ± 118	0.24	177 ± 620	213 ± 378	74 ± 118	0.48
ACPAS (+), (%)	74/90 (82.2)	15/25 (60.0)	0.03	47/56 (83.9)	27/34 (79.4)	15/25 (60.0)	0.06
Anti-CCP2 (RU/mL), mean ± SD	107 ± 126	82 ± 106	0.37	106 ± 120	108 ± 136	82 ± 106	0.67
Anti-CCP2 (+), n (%)	58/87 (66.7)	13/25 (52)	0.24	39/55 (70.9)	19/32 (59.4)	13/25 (52.0)	0.23
Anti-MCV (U/mL), mean ± SD	280 ± 363	82 ± 164	<0.0001	271 ± 343	295 ± 399	82 ± 164	0.06
Anti-MCV (+), n (%)	59/88 (67.0)	7/21 (33.3)	0.005	37/55 (67.3)	22/33 (66.7)	7/21 (33.3)	0.02
OPG serum levels (pg/mL), mean ± SD	104.0 ± 73.9	118.4 ± 61.1	0.24	115.0 ± 84.5	85.6 ± 46.9	118.4 ± 61.1	0.03
Treatment characteristics
cs-DMARD use, n (%)	106 (80.9)	36 (80.0)	1.00	66 (80.5)	40 (81.6)	36 (80.0)	0.66
Monotherapy, n (%)	35 (26.7)	16 (35.6)	0.47	24 (29.3)	11 (22.4)	16 (35.6)	0.66
Combinated therapy, n (%)	71 (54.2)	20 (44.4)		42 (51.2)	29 (59.2)	20 (44.4)
Methotrexate, n (%)	72 (55.0)	23 (51.1)	0.73	44 (53.7)	30 (61.2)	23 (51.1)	0.57
Leflunomide, n (%)	43 (32.8)	13 (28.9)	0.71	24 (29.3)	19 (38.8)	13 (28.9)	0.51
Sulfasalazine, n (%)	38 (29.0)	9 (20.0)	0.25	26 (31.7)	12 (24.5)	9 (20.0)	0.35
Azathioprine, n (%)	20 (15.3)	7 (15.6)	1.00	13 (15.9)	7 (14.3)	7 (15.6)	1.00
Chloroquine, n (%)	17 (13.0)	8 (17.8)	0.46	12 (14.6)	5 (10.2)	8 (17.8)	0.57
Glucocorticoid use, n (%)	109 (83.2)	35 (77.8)	0.50	57 (69.5)	35 (71.4)	33 (73.3)	0.91
Glucocorticoid dose (mg), mean ± SD	6.6 ± 8.7	4.8 ± 3.3	0.23	4.7 ± 6.1	6.4 ± 10.2	4.8 ± 3.3	0.37

BMD: bone mineral density; anti-CCP2: 2nd-generation antibodies against citrullinated proteins; anti-MCV: antimutated citrullinated vimentin antibodies; ACPAs: antibodies against cyclic citrullinated peptides/proteins including anti-CCP2 (+) or anti-MCV (+); cs-DMARD: conventional synthetic disease-modifying antirheumatic drugs; DAS28: Disease Activity Score for 28 joints; HAQ-DI: Health Assessment Questionnaire-disability index; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; RF: rheumatoid factor. Anti-CCP2 (+) was defined as >5 relative units (RU/mL); anti-MCV (+) was defined as >20 RU/mL; combined therapy was defined as the use of two or more cs-DMARDs. Qualitative variables were expressed in frequencies (%) and quantitative variables in means ± standard deviations (SD). Statistical tests: the chi-square test (or the Fisher exact test if applicable) was conducted for comparisons between proportions and independent sample Student t-tests were conducted for comparisons between means, and values were obtained comparing low BMD versus normal BMD. Low BMD (including osteopenia or osteoporosis) (T-score ≤ −1 SD). Comparisons between differences in means were performed using one-way ANOVA. Dunnett correction was used as the post hoc test in case of statistical significance in the ANOVA. values were obtained comparing OP (T-score ≤ −2.5 SD), osteopenia (T-score between −1.0 and −2.5 SD), and normal BMD (T-score ≥ −1 SD). Statistical significance between OP and osteopenia groups (); statistical significance between normal BMD and OP groups (); statistical significance between normal BMD versus osteopenia groups ().