Dataset Information

The association of urine osmolality with decreased kidney function and/or albuminuria in the United States.

ABSTRACT:

Background

Decreased kidney function is commonly caused by hypovolemia. When hypovolemic, the kidney reabsorbs water resulting in concentrated urine. Osmolality is a measure of urine concentration which is more objective than self-reported fluid intake. It has a positive association with hypovolemia. However, it remains controversial whether osmolality is associated with decreased kidney function and/or albuminuria.

Methods

We conducted a cross-sectional analysis of the 2009-2012 National Health and Nutrition Examination Survey, a standardized survey in the U.S.

Population

Participants aged 18-70 years old with random urine osmolality were included. Osmolality was categorized as quartiles. Decreased kidney function was defined by estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m² and albuminuria was defined by albumin-to-creatinine ratio ≥ 30 mg/gm. We performed multivariable regression via four sequential models.

Results

Our study sample included 7,373 participants. The mean age was 42.9 ± 0.4 years. Overall, 51.4% were male and 67.3% were white. The mean osmolality was 603.8 mOsm/kg and 629.1 mOsm/kg in those with and without decreased eGFR and/or albuminuria, respectively. The number of cases was 610 (6.7%). The prevalence from the lowest to highest quartiles of osmolality was 116 (6.2%), 213 (8.6%), 179 (7.5%), and 102 (4.3%), respectively (p-value for trend = 0.02). The relationship between osmolality and eGFR appeared nonlinear. After adjustment for demographic, social, cardiovascular, and dietary risk factors, there was no significant association of osmolality quartiles with decreased eGFR and/or albuminuria (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.56, 1.07). In sensitivity analyses, osmolality ≥ 500 mOsm/kg was associated with lower eGFR (adjusted ß -1.13, 95% CI -1.98, -0.28). In pre-specified subgroup analyses, osmolality had a statistically significant negative correlation with eGFR among individuals with eGFR ≥ 60 mL/min/1.73m², but a positive correlation among those with eGFR < 60 mL/min/1.73m² (adjusted ß -0.19, 95% CI -0.36, -0.01 versus adjusted ß 0.50, 95% CI 0.05, 0.96; p-value for interaction = 0.016).

Conclusions

Higher osmolality was significantly associated with lower eGFR among adults with eGFR ≥ 60 mL/min/1.73m² Future research should examine the relationship between osmolality and change in kidney function over time among adults with normal eGFR.

SUBMITTER: Kitiwan BK

PROVIDER: S-EPMC8434733 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Decreased kidney function and kidney damage may predate hypertension, but only a few studies have investigated both types of markers simultaneously, and these studies have obtained conflicting results.Cross-sectional for prevalent and prospective observational study for incident hypertension.9,593 participants from the ARIC (Atherosclerosis Risk in Communities) Study, aged 53-75 years in 1996-1998.Several markers of kidney function (estimated glomerular filtration rate using serum creatinine and/or cystatin C and 2 novel markers [?-trace protein and ?2-microglobulin]) and 1 marker of kidney damage (urinary albumin-creatinine ratio [ACR]). Every kidney marker was categorized by its quintiles (top quintile as a reference for estimated glomerular filtration rates and bottom quintile for the rest).Prevalent and incident hypertension.Prevalence ratios and HRs of hypertension based on modified Poisson regression and Cox proportional hazards models, respectively.There were 4,378 participants (45.6%) with prevalent hypertension at baseline and 2,175 incident hypertension cases during a median follow-up of 9.8 years. Although all 5 kidney function markers were associated significantly with prevalent hypertension, prevalent hypertension was associated most notably with higher ACR (adjusted prevalence ratio, 1.60 [95% CI, 1.50-1.71] for the highest vs lowest ACR quintile). Similarly, ACR was associated consistently with incident hypertension in all models tested (adjusted HR, 1.28 [95% CI, 1.10-1.49] for top quintile), while kidney function markers demonstrated significant associations in some, but not all, models. Even mildly increased ACR (9.14-14.0mg/g) was associated significantly with incident hypertension.Self-reported use of antihypertensive medication for defining incident hypertension, single assessment of kidney markers, and relatively narrow age range.Although all kidney markers were associated with prevalent hypertension, only elevated albuminuria was associated consistently with incident hypertension, suggesting that kidney damage is related more closely to hypertension than moderate reduction in overall kidney function.

Project description:BackgroundHyperuricemia is commonly observed in patients with chronic kidney disease (CKD). However, a better understanding of the relationship among uric acid (UA) values, glomerular filtration rate (GFR) and albuminuria may shed light on the mechanisms underlying the excess of cardiovascular mortality associated with both chronic kidney disease and hyperuricemia and lead to better risk stratification. Our main goal was to study the relationships between serum uric acid and kidney disease measures (namely estimated GFR [eGFR] and albuminuria) in a large cohort of individuals at cardiovascular risk from the URic acid Right for heArt Health (URRAH) Project database.MethodsClinical data of 26,971 individuals were analyzed. Factors associated with the presence of hyperuricemia defined on the basis of previously determined URRAH cutoffs for cardiovascular and all-cause mortality were evaluated through multivariate analysis. Chronic kidney disease was defined as eGFR < 60 ml/min per 1.73 m2 and/or abnormal urinary albumin excretion diagnosed as: (i) microalbuminuria if urinary albumin concentration was > 30 and ≤ 300 mg/L, or if urinary albumin-to-creatinine ratio (ACR) was > 3.4 mg/mmol and ≤ 34 mg/mmol; (ii) macroalbuminuria if urinary albumin concentration was > 300 mg/L, or if ACR was > 34 mg/mmol.ResultsMean age was 58 ± 15 years (51% males, 62% with hypertension and 12% with diabetes), mean eGFR was 81 ml/min per 1.73m22with a prevalence of eGFR < 60 and micro- or macroalbuminuria of 16, 15 and 4%, respectively. Serum uric acid showed a trend towards higher values along with decreasing renal function. Both the prevalence of gout and the frequency of allopurinol use increased significantly with the reduction of eGFR and the increase in albuminuria. Hyperuricemia was independently related to male gender, eGFR strata, and signs of insulin resistance such as body mass index (BMI) and triglycerides.ConclusionsThe lower the eGFR the higher the prevalence of hyperuricemia and gout. In subjects with eGFR < 60 ml/min the occurrence of hyperuricemia is about 10 times higher than in those with eGFR > 90 ml/min. The percentage of individuals treated with allopurinol was below 2% when GFR was above 60 ml/min, it increased to 20% in the presence of CKD 3b and rose further to 35% in individuals with macroalbuminuria.