Table 4. Correlation Between Serum Uric Acid, Serum Uric Acid/Serum Creatinine Ratio and Serum Total Bilirubin, Indirect Bilirubin.

	Parkinson’s disease (n = 61)	Controls (n = 135)	Parkinson’s disease, r (P value) for SUA	Controls, r (P value) for SUA	Parkinson’s disease, r (P value) for SUA/SCr ratio	Controls, r (P value) for SUA/SCr ratio
Total bilirubin, µmol/L	7.92 ± 3.67	6.59 ± 2.78	0.112 (0.391)	0.118 (0.171)	0.164 (0.208)	0.025 (0.773)
Indirect bilirubin, µmol/L	4.52 ± 2.48	3.26 ± 1.82	0.096 (0.460)	0.125 (0.149)	0.204 (0.114)	0.060 (0.493)
SUA, µmol/L	304.22 ± 82.55	324.28 ± 77.66
SUA/SCr ratio	4.12 ± 0.90	4.59 ± 1.04

Data are expressed as mean ± SD. SUA: serum uric acid; SUA/SCr: serum uric acid/serum creatinine.