PURPOSE: Uric acid (UA) has been proposed as a mortality predictor and strong marker for severity in patients with pulmonary arterial hypertension(PAH). Nevertheless, its role in the pediatric population has not been entirely elucidated. We aimed to evaluate which parameters predict high UA levels, and its role as a mortality predictor in a pediatric cohort with non-responsive idiopathic PAH.
METHODS: We prospectively followed 18 patients(mean age 11± 5years) diagnosed with PAH, from 2000 till February 2010(median follow-up 40 mo,C.I.95% 21-58). All received PAH-specific therapy. UA was measured in close temporal proximity to confirmatory catheterization. No patient received Allopurinol. Student-t, One-way ANOVA, X² and Spearman's-Rho/Pearson tests were used according to variable. Multivariate standard/hierarchical regression was used to determine independent associations with UA. Cox-proportional hazards regression was used to address association with survival. UA and creatinine were Log-transformed to improve linearity. Numerical values are expressed as mean± SD. Statistical significance was accepted as p≤ 0.05.
RESULTS: UA was significantly elevated compared to the expected for age group(6.57± 3.37mg/dL VS 4.20± 0.21, p≤ 0.05).No relationship was found with age nor gender. Forty-one percent were on diuretics, although there was no difference in UA-level between groups.Serum creatinine (0.74± 0.37mg/dL) correlated with UA level(R=0.541,p=0.036), however didn't reach significance when controlled for GFR(p=0.353).Presence of foramen ovale made no difference in the UA level. Cardiac index and right atrial pressure showed moderate correlation(R=0.441 and 0.439 respectively) however non-significant. Only WHO-class had a strong correlation (r=0.629,r²=0.39, p=0.014) however did not reach significance in the multiple regression analysis(p=.076). UA hazard-ratio was 1.43 (CI.95%, 1.004-2.043,p=0.047), nevertheless, was not independent from cardiac index nor creatinine level.
CONCLUSION: 1)Although associated with an increase hazard of death, uric acid was not found to be an independent predictor.2)A larger cohort is needed to address its credibility as a marker of severity.
CLINICAL IMPLICATIONS: UA may have a variety of incompletely defined actions in cardiovascular pathology. Whether it reflects an underlying condition, or it has a direct relationship in disease has to be clarified.
DISCLOSURE: Juan Sandoval-Jones, No Financial Disclosure Information; No Product/Research Disclosure Information