Introduction: The number of elderly patients treated in hospital has grown considerably over the last decade compared to any other age group. Fluid and electrolyte abnormalities are found in up to 42% of elderly hospital patients and can also lead to significant morbidity and mortality.
We aimed to assess the prevalence of dehydration in elderly patients admitted to hospital and to assess the effects of the hydration status on clinical outcome.
Methods: Patients 65 years of age and over were recruited on admission to hospital. Patients were also assessed at 48 hours after admission and followed up post discharge. The hydration status was assessed using biochemical markers, including serum and urine osmolality and kidney function tests. Bioelectrical impedance measurements were also recorded to estimate total body water. Dehydration was defined as serum osmolality >300 mOsmol/kg in men and >295 mOsmol/kg in women.
Results: 103 patients were recruited with mean (range) age 81 (65-99) 40%(n = 41) were dehydrated on admission to hospital. 53(n = 55) were reviewed at 48 hours, 44%(n = 24) of which were dehydrated; 42%(n = 10) of these were not dehydrated at admission to hospital. 15%(n = 15) were dehydrated at admission and at 48 hours. There was an associated increase in length of hospital stay (LOS) in patients who were dehydrated on admission and at 48 hours when compared with the euhydrated group, median (range) LOS, 4(2-48) and 2(0-59) respectively, p = 0.026. There was also an association between mortality at 4 months after discharge in patients who were dehydrated on admission and at 48 hours after admission, p = 0.025.
Conclusions: A significant proportion of elderly patients admitted to hospital were dehydrated at admission and at 48 hours, some of which were dehydrated on admission to hospital. Dehydration at admission and at 48 hours was associated with increased length of hospital stay and mortality.