Association between serum urate levels and all-cause mortality, cardiovascular and renal outcomes among gout patients in Singapore

OBJECTIVES: We investigated the longitudinal association between Serum Urate (SU) level and Acute Myocardial Infarction (AMI), Stroke, End Stage Renal Failure (ESRF) and all-cause mortality. DESIGN: We conducted a retrospective hospital-based cohort study of individuals with gout managed in specialist outpatient clinics. Cox proportional hazards regression was used to estimate HR and 95% CI, with adjustments for potential confounders. Where the proportional hazard assumption was violated, stratified Cox regression was applied instead. SETTING: An acute care tertiary hospital in Singapore. PARTICIPANTS: Individuals with a first gout diagnosis between 2007-2017, identified through (i) primary discharge diagnosis, (ii) diagnosis from the Rheumatology SOC (iii) patient history of a clinical encounter at the Rheumatology SOC plus use of urate-lowering therapy/colchicine. MAIN OUTCOME MEASURES: All-cause mortality, AMI, Stroke and ESRF ascertained through data linkage with the National Registry of Diseases Office. RESULTS: The final cohort comprised 2,866 individuals. Post follow-up, there were 800 deaths and 362, 218 and 191 occurrences of AMI, ESRF and stroke respectively. Compared to the reference (second-lowest) SU quartile, being in the highest SU quartile was associated with a significantly increased hazard for mortality (HR:1.66, 95% CI:1.36-2.03), incident ESRF (HR:3.02, 95% CI:2.00-4.56), and increased hazard for incident AMI (HR:1.42, 95% CI:1.06-1.91). The p-trend for all 3 outcomes was significant. No significant association was found between SU quartile and hazard for incident stroke. CONCLUSIONS: This study found that individuals with gout managed at SOC who had higher baseline SU levels had an increased hazard for all-cause mortality, ESRF, and AMI. CLINICAL TRIAL NUMBER: Not applicable.