Community-acquired hypernatremia in elderly and very elderly patients admitted to the hospital: Clinical characteristics and outcomes

BACKGROUND The clinical features, outcome and cost burden of community-acquired hypernatremia (CAH) in elderly and very elderly patients are not well known. Our aim was to investigate the etiologies, reasons for admission, clinical courses, outcomes, complications, and cost assessments of the elderly patients with CAH. MATERIAL/METHODS We conducted a retrospective study in our tertiary hospital. Elderly and very elderly patients evaluated in the emergency department (ED) from January 1, 2010 to December 31, 2010 (n=4960) were included. Totally, 102 patients older than 65 years and diagnosed with CAH were evaluated. The patients were divided into 2 main groups according to their age: elderly (65-74 years old) (group 1) (n=38), and very elderly (>74 years) (group 2) (n=64). RESULTS Our overall observed prevalence of CAH was 2.0% (n=102, 102/4960). In particular, the prevalences of CAH in group 1 and group 2 were 1.0% (38/3651) and 4.8% (64/1309), respectively (p<0.001). Totally, 62 patients had been treated by renin-angiotensin system (RAS) blockers (ie, ACE-inhibitors). Alzheimer's disease had been diagnosed in 46.1% of the subjects. The mean Katz scores at the time of admission were 2.4 ± 1.9 and 1.1 ± 1.0 in group 1 and 2, respectively (p<0.001). The mean cost was higher in group 2 than in group 1 (2407.13 ± 734.54 USD, and 2141.12 ± 1387.14 USD, respectively) (p<0.01). The need for intensive care was significantly greater in group 2 as compared to group 1. CONCLUSIONS The important determinants of "CAH" in elderly subjects are accompanying Alzheimer's disease, oral intake impairment, and concomitant treatment with RAS blockers.