Hypouricemia in Chinese secondary hospital inpatients: a retrospective study on prevalence and determinants

To investigate the prevalence of hypouricemia and explore its possible influencing factors in a secondary hospital. This retrospective study included 17,541 adult inpatients at the Fusui County People’s Hospital (Guangxi, China) in 2024. Patients were categorized as having hypouricemia (n = 234 patients), normouricemia (n = 14,468) or hyperuricemia (n = 2839). Stratified analyses according to sex, age, eGFR and BUN were performed, and Firth logistic regression (FLR) was used to identify associated factors. The prevalence of hypouricemia was 1.33%, which was significantly higher in females (1.72%) than in males (0.87%, P < 0.001). Patients with hypouricemia had significantly higher eGFRs and lower BUN-to-creatinine ratios than patients with normouricemia and hyperuricemia. The prevalence increased with age to a maximum of 60–79 years and then decreased, with the prevalence consistently higher in females. Regression analysis revealed that female sex (OR = 1.50), advanced age (45–59 years: OR = 3.00; 60–79 years: OR = 5.96; ≥ 80 years: OR = 10.90), low BUN levels (< 3.38 mmol/L, OR = 3.95) and high eGFRs (≥ 90 mL/min/1.73 m2, OR = 2.45) were independently associated with hypouricemia. The most common associated conditions were infectious, intracranial, and liver diseases, as well as type 2 diabetes. In summary, the prevalence of hypouricemia was higher in female inpatients. Female sex, advanced age, elevated eGFR (partly reflecting reduced muscle mass in elderly patients), and low BUN were independently associated with hypouricemia, and infectious diseases were the most common comorbidity.