Table 3

Association between total volume of MSU crystal deposition and baseline characteristics

ParameternTotal volume of MSU crystal depositions (cm3)
(n=152)
Age
 Spearman correlation coefficient, r*152–0.11
 P value*0.17
Age categories
 <65 years1000.07 (0.00, 19.53)
 ≥65 years520.07 (0.00, 10.26)
 P value†0.59
Sex
 Male1400.07 (0.00, 19.53)
 Female120.07 (0.00, 0.89)
 P value†0.38
Race categories
 White980.05 (0.00, 19.53)
 Non-white540.11 (0.00, 10.14)
 P value†0.09
Baseline allopurinol dose category
 300 mg1240.06 (0.00, 19.53)
 >300 mg280.26 (0.00, 10.14)
 P value†0.004
Duration on allopurinol (years)
  Spearman correlation coefficient, r*152–0.01
  P value*0.86
Tophus status
 Presence480.21 (0.00, 19.53)
 Absence1040.05 (0.00, 1.23)
 P value†0.001
Number of tophi locations
 None1040.05 (0.00, 1.23)
 1 location only210.07 (0.00, 3.05)
 2 locations90.07 (0.00, 2.57)
 >2 locations181.31 (0.00, 19.53)
 P value‡0.0001
Duration of gout since diagnosis (years)
  Spearman correlation coefficient, r*1520.18
  P value*0.03
Gout flares in the past 12 months
 None700.05 (0.00, 2.57)
 ≥1820.11 (0.00, 19.53)
 P value†0.01
Gout flares in the past 3 months
 None1100.05 (0.00, 10.26)
 ≥1420.11 (0.00, 19.53)
 P value†0.01
Medical history of kidney stones
 No1300.07 (0.00, 19.53)
 Yes220.05 (0.00, 2.50)
 P value†0.32
BMI (kg/m²)
 Spearman correlation coefficient, r*1520.13
 P value*0.10
Day 1 sUA
 <6.0 mg/dL770.03 (0.00, 4.63)
 ≥6.0 mg/dL750.09 (0.00, 19.53)
 P value†0.02
Renal function group§
 <90 mL/min1150.06 (0.00, 19.53)
 ≥90 mL/min350.08 (0.00, 10.14)
 P value†0.49
 <60 mL/min360.13 (0.00, 5.11)
 ≥60 mL/min1140.05 (0.00, 19.53)
 P value0.20
C reactive protein (mg/L)
 Spearman correlation coefficient, r*1490.10
 P value†*0.24
  • The median, minimum and maximum total volume of MSU crystal depositions are displayed for all categorical parameters.

  • *Estimates from Spearman correlation.

  • †P value from Wilcoxon Mann-Whitney test.

  • ‡P value from Kruskal-Wallis test.

  • §Renal function group is estimated creatinine clearance based on the Cockcroft-Gault method.

  • BMI, body mass index; MSU, monosodium urate; sUA, serum urate.