Hyperuricemia and Cardiometabolic Risk: Pathogenesis and Updated Clinical Strategies

Background

Hyperuricemia (HUA), defined as elevated serum uric acid (SUA) levels (>420 μmol/L [7.0 mg/dL] in men and postmenopausal women; >360 μmol/L [6.0 mg/dL] in premenopausal women), is a common metabolic disorder. Historically viewed primarily as the precursor to gout and nephrolithiasis, its role in cardiometabolic disease has become a major research focus. Uric acid homeostasis involves complex interactions between purine metabolism, renal excretion, and intestinal excretion, heavily influenced by diet, genetics, and comorbidities like chronic kidney disease (CKD). While observational studies consistently link HUA to hypertension, metabolic syndrome (MetS), CKD, and cardiovascular disease (CVD), its causal contribution versus its role as a biomarker of risk remains a subject of intense investigation.

What’s New

Recent research, particularly from the last two years, has provided deeper mechanistic insights and updated clinical evidence:

1. Association with Cardiometabolic Risk Confirmed: A large (n=24,795) health-examination-based cross-sectional study confirmed a strong association between HUA and elevated cardiometabolic risk (defined as ≥3 components: elevated BP, abdominal obesity, abnormal glucose metabolism, elevated triglycerides, reduced HDL-C). After adjusting for age and sex, HUA was associated with 1.66 times higher odds of elevated cardiometabolic risk (95% CI: 1.53-1.79).
2. Lifestyle Interaction: The same study evaluated a simple three-component lifestyle score (TLS: non-current smoking, non-excessive alcohol, adequate physical activity). While individual components showed complex, sometimes paradoxical associations with risk factors (likely due to reverse causation or unmeasured confounding), the composite TLS did not show a statistically significant association with overall elevated cardiometabolic risk after adjustment, nor did it modify the HUA-cardiometabolic risk association (no significant multiplicative or additive interaction). The study acknowledged the critical limitation of not including dietary intake in the TLS.
3. Mechanistic Updates: Research continues to elucidate HUA’s potential pathogenic mechanisms:
   • Inflammasome Activation: Inhibition of the ABCG2 transporter promotes intracellular uric acid accumulation, enhancing NLRP3 inflammasome activation and IL-1β production in macrophages, a key inflammatory pathway.
   • Oxidative Stress: Sleep-disordered breathing (SDB) is linked to overnight increases in SUA, xanthine oxidoreductase (XOR) activity, and oxidative stress markers (8-OHdG) in CAD patients, suggesting a pathway for SDB-mediated vascular damage.
   • Arterial Stiffness & Plaque Instability: Prospective cohort studies confirm HUA is a risk factor for accelerated arterial stiffness progression. Immunohistochemical studies find uric acid more frequently and at higher concentrations in symptomatic versus asymptomatic carotid atherosclerotic plaques.
4. Cardiovascular Risk Thresholds:
   • The URRAH study identified a SUA/serum creatinine ratio >5.35 as an independent predictor of cardiovascular events, applicable across sexes.
   • Age modifies the SUA-mortality relationship: Higher SUA predicts mortality in adults 65-74, while a J-shaped curve emerges in those ≥75, potentially linking low SUA to malnutrition.
5. Preeclampsia Link Strengthened: Elevated SUA (≥240 μmol/L [4.0 mg/dL]) early in pregnancy (<20 weeks) is significantly associated with increased preeclampsia risk. Fructose metabolism may play a role in pathogenesis.
6. Therapeutic Updates (Xanthine Oxidase Inhibitors - XOIs):
   • Cardiorenal Protection: Post-hoc analyses of RCTs suggest benefits of XOIs beyond gout:
     • Febuxostat reduced progression to macroalbuminuria in asymptomatic hyperuricemic elderly (FREED trial).
     • Febuxostat significantly reduced arterial stiffness progression over 24 months compared to lifestyle alone (PRIZE sub-analysis).
     • Canagliflozin (SGLT2i) reduced SUA and plasma volume in HFpEF patients (CANDLE sub-analysis).
   • Withdrawal Syndrome: Large database analyses (e.g., J-ROAD registry) and CARES trial re-analyses indicate a significantly increased mortality risk in cardiovascular patients who discontinue XOIs compared to continuous users or non-users. This highlights the critical importance of avoiding abrupt discontinuation.
   • Optimal Targets: Post-hoc analysis of the Excited-UA trial suggests excessively low SUA levels (<3 mg/dL) may not be optimal for improving microvascular endothelial function in HF patients treated with XOIs, supporting a potential U-shaped curve.

Clinical & Practice Impact

• Diagnosis & Screening: HUA should be recognized as a biomarker significantly associated with elevated cardiometabolic risk. While not routinely screened for asymptomatic individuals in all guidelines, its presence warrants evaluation for associated conditions (hypertension, dyslipidemia, diabetes, CKD).
• Lifestyle Counseling: Emphasize comprehensive lifestyle modifications for overall cardiometabolic health, including:
  • Diet: Limit purine-rich foods (organ meats, shellfish, red meat), sugar-sweetened beverages (fructose), and alcohol (especially beer). Encourage dairy, vegetables, and coffee (associated with lower SUA).
  • Weight Management: Obesity is a major driver of HUA and insulin resistance.
  • Hydration & Avoidance of Dehydration.
  • The limitations of simple lifestyle scores omitting diet should be acknowledged.
• Pharmacotherapy (XOIs) - Evolving Considerations:
  • Gout: Treat-to-target ULT remains standard for gout management (ACR 2020 Guidelines).
  • Asymptomatic Hyperuricemia: Routine ULT for asymptomatic HUA to prevent CVD is not yet recommended due to lack of definitive RCT evidence proving causality and benefit. Management focuses on controlling associated risk factors.
  • Cardiorenal Protection: Evidence suggests potential benefits of XOIs (especially febuxostat) for slowing CKD progression (e.g., reducing macroalbuminuria) and arterial stiffness in specific high-risk populations (e.g., hyperuricemic CKD/hypertensive patients, elderly with CVD). Decisions should be individualized, weighing risks/benefits, until clearer guideline recommendations emerge.
  • XOI Withdrawal Syndrome: CRITICAL ALERT: Discontinuing XOIs in cardiovascular patients appears associated with significant harm. If ULT is started, it should generally be continued lifelong. Tapering or discontinuation requires strong justification and careful monitoring.
• Pregnancy: Monitor SUA early in pregnancy as a potential predictor of preeclampsia risk, especially in women with CKD.

Bottom Line

Hyperuricemia is a robust biomarker associated with increased cardiometabolic risk, hypertension, arterial stiffness, CKD progression, and adverse pregnancy outcomes (preeclampsia). While its exact causal role in CVD remains under study, mechanistic insights into inflammation, oxidative stress, and vascular injury are strengthening. Lifestyle modification targeting diet, weight, and hydration is fundamental management. Pharmacotherapy with XOIs (allopurinol, febuxostat) is essential for gout management. Emerging evidence suggests potential cardiorenal protective benefits of XOIs in specific high-risk asymptomatic hyperuricemic populations, but routine use solely for this indication is not yet standard practice. Crucially, abrupt discontinuation of XOIs in patients with cardiovascular disease is potentially harmful and should be avoided. Management requires an individualized approach, prioritizing control of all associated risk factors.