title: Increased acid excretion in kidney stone formers with essential hypertension.
abstract: BACKGROUND
  Although several studies have reported that kidney stone disease and hypertension are associated, the link between the two conditions has not been identified. This study investigated urinary excretion of different solutes, particularly citrate and acids, in kidney stone formers and examined their association with high blood pressure.
  
  
  METHODS
  The retrospective study included 234 consecutive subjects, aged 47.0 +/- 15.6, attending our metabolic clinic after episodes of kidney stones. Essential hypertension was present in 82 patients (35.0%). A difference in the urinary excretion of some of the investigated components was found between subjects with normal blood pressure and those with hypertension.
  
  
  RESULTS
  The results showed that hypertensive subjects were older and had a higher body mass index (BMI) and serum uric acid. They had a significantly lower urinary pH (5.6 +/- 0.4 versus 6.0 +/- 0.5) and citrate (2.55 +/- 1.36 versus 2.83 +/- 1.65 mmol/24 h), higher titratable acid (38.8 +/- 19.0 versus 26.8 +/- 15.0 mEq/24 h) and ammonium (41.6 +/- 17.6 versus 34.2 +/-12.4 mmol/24 h). Logistic regression analysis with the presence of hypertension as the dependent variable produced a model with the following predictors: age (P < 0.0001), BMI (P = 0.026), titratable acid (P = 0.025) and low urinary citrate level (P = 0.033). Urinary acid excretion increased with the stage of hypertension. No difference was found in the urinary excretion of other solutes.
  
  
  CONCLUSIONS
  These findings suggest that essential hypertension and acid excretion are linked in stone formers.
authors: Struttura Complessa Nefrologia e Dialisi, Università degli studi di Perugia, Perugia, Italy. alosito3@gmail.com
authors: Attilio
authors: A
authors: Losito
authors: Emidio Giovanni
authors: EG
authors: Nunzi
authors: Carla
authors: C
authors: Covarelli
authors: Elisabetta
authors: E
authors: Nunzi
authors: Gaetano
authors: G
authors: Ferrara
mesh_terms: D000143:Acids / Q000652:urine*; D000328:Adult; D019343:Citric Acid / Q000652:urine; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006973:Hypertension / Q000150:complications*; D007669:Kidney Calculi / Q000150:complications* / Q000652:urine*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D000143:Acids; D019343:Citric Acid