Clinical relevance of hyponatraemia for the hospital outcome of cirrhotic patients

Background. Hyponatraemia frequently develops in cirrhotic patients whose ability to excrete free water is impaired. The role of hyponatraemia in the prognosis of such patients is unclear. Aim. To evaluate prevalence, clinical associations and prognostic impact of hyponatraemia in cirrhotic inpatients. Patients. A series of 156 cirrhotic patients consecutively admitted to our department, for a total of 191 admissions, were studied. Methods. Serum sodium levels were determined at admission and repeated at least weekly in all patients. The clinical status and the survival of patients with hyponatraemia (less than or equal to 130 mmol/l) were compared to those of patients with normal sodium levels. Results. Hyponatraemia was found in 57 out of 191 admissions (29.8%). Bacterial infections, ascites, chronic diuretic therapy, but not gastrointestinal bleeding or renal failure, were more frequent in patients with hyponatraemia than in those with normal sodium levels. In 3 cases, none of these conditions were present and hyponatraemia was defined as "spontaneous': Hospital death rate was increased in patients with hyponatraemia (26.3% versus 8.9%, chi (2)=8.55, p=0.003). By multivariate analysis, the only parameters independently associated with survival were high serum bilirubin (p=0.006) and high serum urea levels (p=0.019). Twenty-five patients developed severe hyponatraemia (<125 mmol/l] during hospital stay. This event was associated with a concomitant bacterial infection in 21 cases. The mortality rate of these patients was very high (48%). Conclusions. Hyponatraemia is frequent in cirrhotic inpatients. It is seldom a spontaneous event but rather occurs in association with ascites, chronic use of diuretics or bacterial infections. It is a negative prognostic factor associated with increased short-term mortality.