Effect of low-purine diet on the serum uric acid of gout patients in different clinical subtypes: a prospective cohort study.

Background: The pathogenic causes of primary gout include urate overproduction and/or renal or extra-renal urate underexcretion. The aim of this study was to evaluate the association of gout subtypes with the response to low-purine diet (LPD).

Methods: This is a single-center prospective clinical study. Gout patients visiting from 2019 to 2022, from Shandong Gout Clinic Center at the Affiliated Hospital of Qingdao University, China, assigned to three groups according to clinical subtypes, were enrolled and all treated with 2-week low-purine diet. General characteristics, serum uric acid (sUA) and other clinical biochemical variables before and after the diet were evaluated.

Results: A total of 626 gout patients (age 41.20 ± 13.41 years, male 98.0%) were included. Of these, 69 (11.0%) were overproduction type, 428 (68.37%) were underexcretion type, and 129 (20.61%) were combined type. Overall, there was a substantial decrease in sUA after a 2-week LPD (p < 0.001). In addition, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), serum triglycerides (TG), serum total cholesterol (TC), blood urea nitrogen (BUN) and serum creatinine (Scr) levels were lower than those at baseline (p < 0.05). On the other hand, there were significant differences in the reduction of sUA among different types, the rank order being overproduction type (- 88.81 ± 63.01 μmol/L) > combined type (- 65.22 ± 44.13 μmol/L) > underexcretion type (- 57.32 ± 61.19 μmol/L). After adjusting for age, BMI and baseline sUA and eGFR, there were still significant differences in the decline of serum uric acid among different types. Higher baseline sUA (95%CI - 0.285, - 0.191; p < 0.001) and BUN (95%CI - 6.751, - 0.602; p < 0.001) were correlated with greater decrease of sUA.

Conclusions: Our findings support the protective role of low-purine diet on sUA levels in gout patients, especially overproduction type. Furthermore, LPD could exert a beneficial effect on gout patients' blood pressure, BMI, blood lipid, BUN and Scr levels. Trial registration Registered with ChiCTR, No. ChiCTR1900022981 at 06/05/2019.