Is Serum Uric Acid Level Associated with Disease Activity in Rheumatoid Arthritis Patients

Figures & data

Table 1 Comparison of Disease Activity of the Two Groups

	High UA (N=884)	Low UA (N=5436)	Total (N=6320)	P value
Morning Stiffness				< 0.001
Mean (SD)	7.2 (14.6)	11.7 (22.0)	10.9 (20.9)
Range	0.0–120.0	0.0–240.0	0.0–240.0
Number of Swollen joints				< 0.001
Mean (SD)	0.7 (2.3)	1.0 (2.6)	1.0 (2.5)
Range	0.0–24.0	0.0–31.0	0.0–31.0
Number of Tender joints				0.964
Mean (SD)	2.4 (5.0)	2.4 (4.7)	2.4 (4.8)
Range	0.0–30.0	0.0–57.0	0.0–57.0
ESR				0.066
Mean (SD)	32.3 (26.9)	30.7 (23.4)	30.9 (23.9)
Range	0.0–134.0	0.0–130.0	0.0–134.0
CRP				0.715
Mean (SD)	6.2 (5.4)	6.2 (5.0)	6.2 (5.1)
Range	0.0–21.0	0.0–21.0	0.0–21.0
HAQ				0.001
Mean (SD)	1.1 (0.7)	0.9 (0.6)	0.9 (0.6)
Range	0.1–2.9	0.1–3.0	0.1–3.0
Patient Global Assessment				0.725
Mean (SD)	1.4 (2.2)	1.3 (2.2)	1.4 (2.2)
Range	0.0–9.0	0.0–10.0	0.0–10.0
Physician Global Assessment				0.170
Mean (SD)	0.9 (1.7)	1.0 (1.7)	0.9 (1.7)
Range	0.0–9.0	0.0–10.0	0.0–10.0
VAS Pain				0.184
Mean (SD)	1.3 (2.2)	1.2 (2.1)	1.2 (2.1)
Range	0.0–9.0	0.0–10.0	0.0–10.0
DAS28				0.054
Mean (SD)	2.7 (1.4)	2.8 (1.3)	2.7 (1.3)
Range	0.0–7.3	−1.6–9.7	−1.6–9.7

Abbreviations: ESR, erythrocyte sedimentation rate; CRP, C reactive protein; HAQ, Health Assessment Questionnaire; VAS, visual analogue scale; DAS-28, Disease Activity Score.

Table 2 Demographic and Serological Characteristics of the Two Groups

	High UA (UA ≥ 357) (N=158)	Low UA (UA < 357) (N=896)	Total (N=1054)	P value
Age (years)				< 0.001
Mean (SD)	59.3 (10.7)	54.5 (12.4)	55.2 (12.3)
Range	26.0–81.7	16.8–86.8	16.8–86.8
Gender				0.002
female	78.0 (49.4%)	557.0 (62.2%)	635.0 (60.2%)
Duration of RA (years)				0.823
Mean (SD)	10.5 (7.1)	10.3 (6.9)	10.3 (7.0)
Range	0.2–39.8	0.2–55.8	0.2–55.8
Smoking				0.066
Yes	18.0 (14.2%)	57.0 (8.9%)	75.0 (9.8%)
DM				0.185
Yes	36.0 (22.8%)	164.0 (18.3%)	200.0 (19.0%)
Hypertension				< 0.001
Yes	49.0 (31.0%)	170.0 (19.0%)	219.0 (20.8%)
CAD				0.054
Yes	8.0 (5.1%)	21.0 (2.3%)	29.0 (2.8%)
Creatinine				< 0.001
Mean (SD)	82.7 (61.6%)	61.5 (21.4%)	64.4 (31.3%)
Range	4.0–767.0	0.5–575.0	0.5–767.0
Family History of AIA				0.856
Positive	19.0 (16.4%)	106.0 (17.1%)	125.0 (17.0%)
Negative	97.0 (83.6%)	515.0 (82.9%)	612.0 (83.0%)
RF				0.654
Positive	112.0 (75.2%)	631.0 (76.9%)	743.0 (76.6%)
Negative	37.0 (24.8%)	190.0 (23.1%)	227.0 (23.4%)
ANA				0.305
Positive	41.0 (33.1%)	204.0 (28.5%)	245.0 (29.2%)
Negative	83.0 (66.9%)	511.0 (71.5%)	594.0 (70.8%)
ANTI CCP				0.036
Positive	95.0 (77.2%)	491.0 (67.8%)	586.0 (69.2%)
Negative	28.0 (22.8%)	233.0 (32.2%)	261.0 (30.8%)
On Biologics/DMARDs				0.722
Biologics	60.0 (38.5%)	347.0 (40.0%)	407.0 (39.7%)
cDMARDs	96.0 (61.5%)	521.0 (60.0%)	617.0 (60.3%)
Combination	41.0 (25.9%)	222.0 (24.8%)	263.0 (25.0%)
None	2.0 (1.3%)	28.0 (3.1%)	30.0 (2.8%)
On Steroid				0.725
No	132.0 (89.2%)	749.0 (90.1%)	881.0 (90.0%)
Yes	16.0 (10.8%)	82.0 (9.9%)	98.0 (10.0%)
On NSAIDs				0.604
Intermittent use	80.0 (93.0%)	533.0 (95.3%)	613.0 (95.0%)
Regular use	5.0 (5.8%)	23.0 (4.1%)	28.0 (4.3%)

Abbreviations: DM, diabetes mellitus; CAD, coronary artery disease; AIA, autoimmune arthritis; RF, rheumatoid factor; anti CCP, anti-cyclic citrullinated peptide antibodies; ANA, anti-nuclear antibodies; cDMARDs, conventional disease modifying anti-rheumatic drugs.

Table 3 Logistic Regression

Dependent: UAD.Group		High UA	Low UA	OR (Multivariable)
DAS28 score	DAS28 < 3.2	646 (14.4)	3831 (85.6)	-
	DAS28 ≥ 3.2	237 (12.9)	1604 (87.1)	1.39 (1.03–1.90, p=0.032)
Creatinine level	Low Creatinine	784 (12.9)	5271 (87.1)	-
	High Creatinine	93 (47.2)	104 (52.8)	0.24 (0.12–0.46, p<0.001)
Treatment*	No	366 (10.9)	2988 (89.1)	-
	Yes	518 (17.5)	2448 (82.5)	1.24 (0.90–1.71, p=0.185)
Gender	Female	437 (13.1)	2905 (86.9)	-
	Male	447 (15.0)	2531 (85.0)	1.06 (0.76–1.51, p=0.740)
Age years	Mean (SD)	59.2 (12.1)	54.9 (11.9)	0.99 (0.98–1.00, p=0.102)
HAQ	Mean (SD)	1.1 (0.7)	0.9 (0.6)	0.78 (0.63–0.96, p=0.019)
On Steroid	No	798 (14.5)	4716 (85.5)	-
	Yes	57 (10.6)	479 (89.4)	1.95 (1.05–3.99, p=0.048)

Note: *Treatment including DMARDs/Biological.

Abbreviations: DAS-28, Disease Activity Score; HAQ, Health Assessment Questionnaire.

Figure 1 Plot chart correlation between UA and creatinine levels in both genders.

Figure 2 Plot chart correlation between UA and creatinine levels in high and low DAS28 scores.

Figure 3 Forest plot of multivariable logistic regression analysis.