Objective: To determine the relationship between serum uric acid (SUA) concentrations of 6.8 mg% or less on the future risk of hypertension (HT).

Materials and Methods: People aged at least 15 years old, without HT, who visited for physical checkups, either at the Primary Care Unit, General Practice Clinic, General Health Examination Clinic, or the Private General Practice Clinic of Songklanagarind Hospital, between July and December 2008, were included in the present study. Medical records were reviewed until the end of March 2016, either until HT was diagnosed or treatment with any HT drugs started. SUA was categorized into five categories, starting from less than 2.9 to 6.8 mg%. The incidences of HT were reported in terms of person-time incidence. The association between SUA and HT was analyzed and reported in terms of hazards ratios (HRs), using Cox proportional hazards regression model.

Results: After a median of 7.3 years follow-up, with an interquartile range 3.2 years, the study identified 240 and 109 incident cases of HT among 2,253 females and 821 males, respectively. The relationship between SUA and incidence of HT appeared to be a U-shaped association, with the bottom of the curves at 4.9 to 5.8 mg% for males, whereas, in females the relationship between SUA and incidence of HT appeared to be an exponential relationship. In multivariate analysis, comparing each 1 mg% increase in SUA, were 1.3 (95% CI 1.2 to 1.5, p<0.01) in females and 1.0 (95% CI 0.8 to 1.3, p=0.99) in males for hypertensive incident.

Conclusion: The results showed that higher SUA concentrations in female gender increase exponentially on HRs of HT. Nonetheless, this effect was not found in males. U-shaped association was found between low SUA concentrations and the person-time incidences of HT in male patients. However, the relationship was not statistically significant in multivariate analysis.

Keywords: Cohort study, Uric acid, Hypouricemia, Essential hypertension

Received 17 Jun 2019 | Revised 2 Sep 2019 | Accepted 9 Sep 2019