High serum uric acid within the normal range is a useful predictor of hypertension among Japanese community-dwelling elderly women

Serum uric acid to creatinine ratio is a useful predictor of all-cause mortality among hypertensive patients

BACKGROUND

Many of the existing research studies have shown that serum uric acid (SUA) is a predictor of renal disease progression. More recently, studies have suggested an association between renal function-normalized SUA and all-cause mortality in adults. This study aims to examine the association between the ratio of SUA to creatinine (SUA/Cr) and all-cause mortality with a focus on hypertensive patients.

METHODS

This study is based on 2,017 participants, of whom 916 were male (mean age, 67 ± 11 years) and 1,101 were female (mean age, 69 ± 9 years). All participants were part of the Nomura Cohort Study in 2002 (cohort 1) and 2014 (cohort 2), as well as the follow-up period (2002 follow-up rate, 94.8%; 2014 follow-up rate, 98.0%). We obtained adjusted relative risk estimates for all-cause mortality from a basic resident register. In addition, we employed a Cox proportional hazards model and adjusted it for possible confounders to determine the hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Of the total participants, 639 (31.7%) were deceased; of these, 327 (35.7%) were male and 312 (28.3%) were female. We found an independent association between a higher ratio of SUA/Cr and a higher risk of all-cause mortality in female participants only (HR, 1.10; 95% CI, 1.02-1.18). The multivariable-adjusted HRs (95% CI) for all-cause mortality across quintiles of baseline SUA/Cr were 1.28 (0.91-1.80), 1.00, 1.38 (0.95-1.98), 1.37 (0.94-2.00), and 1.57 (1.03-2.40) for male participants, and 0.92 (0.64-1.33), 1.00, 1.04 (0.72-1.50), 1.56 (1.06-2.30), and 1.59 (1.06-2.38) for female participants. When the data were further stratified on the basis of age (< 65 or ≥ 65 years), body mass index (< 22.0 or ≥ 22.0 kg/m²), estimated glomerular filtration rate (< 60 or ≥ 60 mL/min/1.73 m²), and presence of SUA-lowering medication, trends similar to those of the full population were found in all groups.

CONCLUSION

Baseline SUA/Cr is independently and significantly associated with future all-cause mortality among hypertensive patients.

Change in Serum Uric Acid is a Useful Predictor of All-Cause Mortality among Community-Dwelling Persons

There is limited research on the association between longitudinal variability in serum uric acid (SUA) and all-cause mortality in the general population, although recent studies have suggested that changes in SUA are associated with all-cause mortality in adults. This study aims to examine the association between percentage change in SUA (%dSUA = 100 × (cohort 2 SUA - cohort 1 SUA)/(time × cohort 1 SUA) and all-cause mortality. This study is based on 1,301 participants, of whom 543 were male (63 ± 11 years) and 758 were female (63 ± 9 years). We obtained adjusted relative risk estimates for all-cause mortality and used a Cox proportional hazards model, adjusted for possible confounders, to determine the hazard ratio (HR) and 95% confidence interval (CI) of %dSUA. Of all the participants, 79 (6.1%) were deceased, and of these, 45 were male (8.3%) and 34 were female (4.5%). The multivariable-adjusted HRs (95% CI) for all-cause mortality for the first, second to fourth (reference), and fifth %dSUA quintiles were 3.79 (1.67-8.48), 1.00, and 0.87 (0.29-2.61) for male participants and 4.00 (1.43-11.2), 1.00, and 1.19 (0.46-3.05) for female participants, respectively. Participants with a body mass index of <22 kg/m² had a significantly higher HR, forming a U-shaped curve for the first (HR, 7.59; 95% CI, 2.13-27.0) and fifth quintiles (HR, 2.93; 95% CI, 1.05-8.18) relative to the reference. Percentage change in SUA is independently and significantly associated with future all-cause mortality among community-dwelling persons.

Purine metabolites and complex diseases: role of genes and nutrients

PURPOSE OF REVIEW

Purines have several important physiological functions as part of nucleic acids and as intracellular and extracellular signaling molecules. Purine metabolites, particularly uric acid, have been implicated in congenital and complex diseases. However, their role in complex diseases is not clear and they have both beneficial and detrimental effects on disease pathogenesis. In addition, the relationship between purines and complex diseases is affected by genetic and nutritional factors. This review presents latest findings about the relationship between purines and complex diseases and the effect of genes and nutrients on this relationship.

RECENT FINDINGS

Evidence from recent studies show strong role of purines in complex diseases. Although they are causal in only few diseases, our knowledge about their role in other diseases is still evolving. Of all the purines, uric acid is the most studied. Uric acid acts as an antioxidant as well as a prooxidant under different conditions, thus, its role in disease also varies. Other purines, adenosine and inosine have been less studied, but they have neuroprotective properties which are valuable in neurodegenerative diseases.

SUMMARY

Purines are molecules with great potential in disease pathogenesis as either metabolic markers or therapeutic targets. More studies need to be conducted to understand their relevance for complex diseases.