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Urinary calcium excretion in treated and untreated essential hypertension
Insights
Hypercalciuria, or high urinary calcium, is common in untreated essential hypertension. Certain blood pressure medications like thiazides and beta-blockers can reduce this risk.
Area of Science:
- Nephrology
- Cardiology
- Metabolic Disorders
Background:
- Essential hypertension is frequently associated with hypercalciuria.
- The clinical and therapeutic significance of hypercalciuria in hypertension remains understudied.
Purpose of the Study:
- To determine the prevalence of hypercalciuria in essential hypertension patients.
- To analyze the relationship between urinary calcium levels and clinical/therapeutic status.
- To investigate the impact of antihypertensive medications on calciuria and uricosuria.
Main Methods:
- Prospective study of 112 essential hypertension patients and 49 healthy controls.
- Measured urinary excretion of calcium, sodium, urate, and other parameters.
- Assessed serum levels of electrolytes, creatinine, uric acid, and hormones.
Main Results:
- Untreated hypertensive patients showed a significantly higher prevalence of hypercalciuria (35%) compared to treated patients (20%) and controls (2%).
- Thiazide and beta-blocker monotherapy reduced urinary calcium and urate excretion.
- Higher urinary calcium correlated with increased sodium and urate excretion, higher creatinine clearance, and lower serum creatinine and uric acid.
Conclusions:
- Hypercalciuria is a frequent finding in untreated essential hypertension.
- The co-occurrence of high urinary calcium and urate may increase lithiasis risk.
- Antihypertensive drugs differentially affect calciuria and uricosuria, influencing lithogenic risk.
Abstract:
A high prevalence of hypercalciuria has been reported in patients with essential hypertension. Nevertheless, the clinical and therapeutic implications of this finding have scarcely been studied. This study was designed to determine the prevalence of hypercalciuria in an unselected population with essential hypertension and to analyze the relationship between the urinary calcium and the clinical and therapeutic status of these patients. This article presents a prospective study of 112 patients with essential hypertension and 49 healthy normotensive control subjects. Urinary excretion rates of calcium, sodium, chloride, potassium, urinary calcium/creatinine index, the fractional excretion of sodium, potassium and uric acid, the creatinine clearance and serum values of creatinine, urea, uric acid, electrolytes, total proteins, parathormone (intact molecule), plasma renin activity, aldosterone, glucose, and insulin (fasting and after an oral glucose load) were performed in every patient and control subject. Untreated hypertensive patients had a higher prevalence of hypercalciuria (35% had a urinary calcium/creatinine ratio > 0.20 versus 20% of treated hypertensives and 2% of control subjects; P < 0.001). Patients on thiazide or beta-blocker monotherapy had lower urinary excretion rates of calcium and urate than patients on calcium-antagonist monotherapy or untreated patients. Urinary calcium, sodium, and urate correlated positively both in treated and untreated essential hypertension patients. Patients with the higher urinary calcium levels also had higher excretion rates of sodium and urate, higher creatinine clearance rates, and lower serum creatinine and serum uric acid levels. It was concluded that hypercalciuria is a frequent finding of untreated essential hypertension. The association of high urinary calcium levels with high urinary urate excretion rates in the same patient may predispose to development of lithiasis in patients with essential hypertension. Antihypertensive drugs have a variable effect on calciuria-uricosuria, which may constitute an additional criterion in the selection and individualization of therapy. Thiazides and beta-blockers can decrease calciuria and uricosuria and, therefore, the lithogenic risk in these patients.