集中治療室への計画外の再入院リスクの潜在的予測因子としての位相角：集中治療室の外科患者を対象とした後ろ向きコホート研究

Surgical intensive care unit (ICU) readmission worsens outcomes; however, prediction remains difficult. Phase angle (PhA), a bioimpedance-derived marker of cellular integrity and nutritional status, may add prognostic value beyond routine clinical indices.

We conducted a single-center retrospective cohort of ICU discharge-level observations (510 discharges) from a surgical ICU. PhA was measured by bioelectrical impedance analysis at ICU admission (PhA0) and discharge (PhAdc). The primary analysis used a mixed-effects logistic regression with a patient-level random intercept to account for multiple discharges per patient. Pre-specified cutoffs (PhA0 ≤ 3.75°, PhAdc ≤ 2.55°) were derived by internal receiver operating characteristic/Youden methods and assessed with patient-wise fivefold cross-validation. Sensitivity analyses included stepwise multivariable models, first-discharge-only, cluster-robust standard errors, and a reduced generalized estimating equation.

Of 510 discharges, 68 (13.3%) were followed by unplanned ICU readmission. Low PhA0 and low PhAdc were associated with readmission in bivariable analyses. In the primary mixed-effects model, low PhA0 independently predicted readmission [adjusted odds ratio (aOR) = 4.00, 95% confidence interval (CI) 1.82-8.78; P < 0.001], while low PhAdc showed a positive trend (aOR = 1.80, 0.95-3.42; P = 0.07). Emergency surgery was also independently associated (aOR = 4.57, 2.00-10.40; P < 0.001). Findings were directionally consistent across sensitivity analyses.

PhA measured at ICU admission and discharge provides an actionable, noninvasive prognostic indicator for surgical ICU readmission.