The association between malnutrition and dehydration in older adults admitted to a geriatric unit: An observational study.

BACKGROUND AND AIM: There is an overlap between the risk factors causing low intake of water and low intake of nutrients, respectively. This study aims to explore the agreement between the assessment of malnutrition and the outcome of low-intake dehydration in a population of older hospitalized patients. METHODS: Patients ≥65 years old and hospitalized at the geriatric hospital ward were screened for eligibility within 96 h of admission. Dehydration was assessed with the calculated serum osmolarity ≥295 mmol/L (1.86 × (Na+ + K+) + 1.15 × glucose + urea + 14), and (risk of) malnutrition was assessed with NRS-2002 ≥ 3 points, MNA-SF ≤ 7 points, MNA-LF < 17, MUST ≥ 2 points, and GLIM after screening with NRS-2002 and MNA-LF. Follow-up data regarding exercise rehabilitation, readmissions, and mortality was collected 30 days after discharge. Statistics used were the Chi-squared test, Fishers-exact test, and Wilcoxon signed rank test. RESULTS: A total of 114 patients (57% females) were included. Median age 85.5 (IQR 80; 89.25) years. A total of 49 (43%) were dehydrated. Fewer females were dehydrated (F: 42.9% vs. M: 67.7%, p = 0.013). The patients with osmolarity ≥295 mmol/L had a higher median weight (68.3 (IQR 58.5; 78.4) vs. 62 (IQR 51.8; 72.1), p = 0.021) and mid-up-arm circumference (27 (IQR 26; 30) vs. 25.5 (IQR 22.9; 28.3), p = 0.004). No significant difference was found in the prevalence of malnutrition between those with or without dehydration (NRS-2002; 70% vs. 81%, p = 0.174; MNA-SF: 23.1 vs. 23.2%, p = 1.0; MNA-LF: 37.1 vs. 30.2%, p = 0.644; MUST: 24.5 vs. 33.8%, p = 0.308; GLIM after screening with NRS-2002: 84.4 vs. 74.5%, p = 0.405, GLIM after screening with MNA-LF: 74.1 vs. 75.6%, p = 0.438). Kappa values varied around 0 and reflected low agreement. There were no differences in the follow-up data, between those who were normohydrated and those who were dehydrated. CONCLUSION: We found low agreement between the assessment of malnutrition and low-intake dehydration in a population of older hospitalized patients. All geriatric patients should therefore be assessed for both conditions.

Accuracy of the calculated serum osmolarity to screen for hyperosmolar dehydration in older hospitalised medical patients.

BACKGROUND AND AIMS: Simple hyperosmolar dehydration, also termed water-loss dehydration (HD), is common in older hospitalised patients, thus increasing the risk of morbidity and mortality. Directly measured serum osmolality is the reference standard to determine HD; however, it is not a routine test due to its complexity and cost. Thus, a simple valid objective diagnostic tool to detect HD is needed. Consequently, we aimed to validate the agreement between measured s-osmolality (mOsm/kg) and calculated s-osmolarity (mOsm/L). METHODS: Patients aged >65 were included from the emergency medical department at Herlev Hospital, Copenhagen, Denmark. Exclusion criteria were: eGFR< 30 mmol/L, severe heart failure, decompensated cirrhosis, alcohol intake or initiated rehydration treatment. We obtained data for measured s-osmolality as well as calculated osmolarity, using the by ESPEN recommended equation [1.86x (Na+ + K+)+1.15 ∗glucose + urea+14]. To determine accuracy, we used cut-off values of >295 mOsm/L versus >300 mOsm/kg. RESULTS: A total of 90 patients (female 53%), age median 78 yrs (72-86 yrs) were included. According to the measured mOsm/kg, impending HD was evident in 32% (n = 10), of these 11% (n = 10) had current HD. There was a significant association between calculated mOsm/L and measured Osm/kg (r2 = 0.7513, p < 0.0001). A sensitivity of 90% (95% CL: 56%-100%), a specificity of 68% (95% CL: 56%-78%), Positive predictive value (PPV) of 26% (95% CL: 12%-43%), and Negative predictive value (NPV) of 98% (95% CL: 90%-100%) were observed. Notably, only 20% (n = 2) of the patients who were dehydrated according to the measured Osm/kg were correctly clinically diagnosed with dehydration. CONCLUSIONS: The equation recommended by ESPEN to calculate osmolarity was found to be an accurate objective diagnostic tool to assess HD in older hospitalised medical patients. The method is markedly superior to the current clinical practice.