Water homeostasis, frailty and cognitive function in the nursing home

Objective To develop and test a practical clinical method to assess frailty in nursing homes; — To investigate the relationship between cognitive status of the elderly and the balance between water compartments of their body composition. Design and subjects Cross-sectional study, conducted at two nursing homes in Boston-MA. Methods Body mass and height (Ht) were evaluated to calculate BMI (body mass index, in Kg/m 2 ). The cognitive decline was evaluated based on the scores obtained from the Mini-Mental State Examination (MMSE); The extracellular to total body water ratio (ECW/TBW) was calculated after the analysis of TBW from deuterium and tritium dilution and ECW from bromide dilution. Single-frequency BIA analysis data were investigated for resistance (R) and reactance (Xc), plotted in an R/Ht Xc/Ht graph (vectorial analysis-BIVA). The BIVA results of nursing home residents were compared against the data obtained from the NHANES III study. TBW and ECW values were compared with a group of free-living elderly volunteers. Results The ECW/TBW was significantly higher in nursing home residents than in the free-living individuals. BIVA analysis showed significantly higher Xc/Ht values in the reference subjects. The MMSE did not present a significant correlation with ECW/TBW for either gender. Conclusion We proposed the ECW/TBW ratio and BIVA as surrogate methods for the clinical assessment of frailty. We tested successfully both approaches with nursing home patients and free-living volunteers and compared them to a national data base. The advent of new, portable instruments will enable field tests to further validate our proposed “Frailty Factor” in future studies. We found no correlation between frailty and cognitive decline in the nursing home.