Salivary uric acid as a noninvasive biomarker for monitoring the efficacy of urate-lowering therapy in a patient with chronic gouty arthropathy.
BACKGROUND
Monitoring blood uric acid (UA) is important in all patients on urate-lowering therapy so that the selection of the effective drugs and dosage adjustments could be made until the target level is reached. The issue is that frequent needle jabs are unacceptable. Reported mean levels of salivary UA were 185-240 μmol/l in healthy adults. A linear correlation was demonstrated between UA concentrations in saliva and plasma. We monitored salivary UA instead of plasmatic UA in a patient with gout.


METHODS
Allopurinol and benzbromarone were used as the therapeutic drugs. Salivary UA; urinary UA and creatinine; and plasmatic UA, creatinine, kynurenine and tryptophan were measured by HPLC.


RESULTS
Salivary UA indicated the efficacy of therapy accurately and conveniently. After eight weeks therapy, the weekly mean levels of salivary UA were reduced and maintained to <300 μmol/l, which was equivalent to <360 μmol/l of plasmatic UA according to the salivary UA/plasmatic UA ratio of this patient.


CONCLUSIONS
Measurement of salivary UA is a noninvasive and useful way for monitoring the status of hyperuricemia and the therapeutic efficacy of urate-lowering therapy. It has value for the management of hyperuricemia and gout.
Ruijin Hospital, Shanghai Jiao Tong University School of Medicine and Shanghai Institute of Hypertension, Shanghai, China. Electronic address: jzhao021@yahoo.com.
Jianxing
J
Zhao
Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Electronic address: daphnehy@sjtu.edu.cn.
Ying
Y
Huang
D015210:Arthritis, Gouty / Q000150:complications / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D001553:Benzbromarone / Q000494:pharmacology / Q000627:therapeutic use; D015415:Biomarkers / Q000378:metabolism; D002908:Chronic Disease; D005240:Feasibility Studies; D006801:Humans; D033461:Hyperuricemia / Q000150:complications; D007668:Kidney / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012463:Saliva / Q000378:metabolism*; D016896:Treatment Outcome; D014527:Uric Acid / Q000378:metabolism*
D015415:Biomarkers; D014527:Uric Acid; D001553:Benzbromarone
Gout; Hyperuricemia; Saliva; Urate-lowering therapy; Uric acid