Association Between Phase Angle and Tongue Pressure in Older Inpatients with Connective Tissue Diseases.

To investigate the association between tongue pressure (TP) and phase angle (PhA) in patients with connective tissue diseases (CTDs) aged 65 years or older. This retrospective cross-sectional study was conducted on 189 patients with CTDs who underwent hospital rehabilitation. TP was measured using a tongue pressure measuring device, and PhA was calculated from the bioimpedance analysis readings. Statistical analyses included multivariate linear regression with TP and receiver operating characteristic curves to determine PhA cutoff values indicative of low TP, defined as < 24.3 kPa for men and < 23.7 kPa for women. A total of 189 patients with CTDs (mean age 75 years; 49 men and 140 women; mean PhA 4.0°; mean TP 27.7 kPa) were included in the analysis. Fifty-five patients had low TP. Patients with low TP had lower PhA values than those with normal TP (mean PhA values 3.5° versus 4.3°). After adjusting for confounding factors, PhA (β = 0.387, p < 0.001) was significantly associated with TP. Cutoff values for PhA predicting low TP were identified as 3.9° for men and 3.5° for women. PhA is associated with TP, independent of other factors, in older inpatients with CTDs. The identified PhA cutoff values could enable the early detection of declining TP.