Phase angle and standardized phase angle from bioelectrical impedance measurements as a prognostic factor for mortality at 90 days in patients with COVID-19: A longitudinal cohort study

Abstract

Background and aims Severe acute COVID-19 has taken on pandemic proportions with growing interest in identification of prognostic factors for mortality. Standardized bioelectrical impedance (BI) phase angle (SPhA), which is PhA adjusted by age and sex, has been related to mortality in patients with several diseases but never investigated in COVID-19. Inflammation, a consequence of COVID-19 infection, affects fluid status (hydration) and can be identified with PhA. The aim of this study was to determine the predictive role of PhA on 90 days survival of adults with COVID-19. Methods We studied 127 consecutive patients diagnosed with COVID-19. BI measurements determined with a 50 kHz phase-sensitive BI device, body composition parameters and laboratory markers were evaluated as predictors of mortality. Results Non-surviving COVID-19 patients had significantly lower PhA and SPhA values (p<0.001) and increased hydration (p<0.001) compared to surviving patients. Patients in the lowest SPhA quartile had increased (p<0.001) mortality and hospital stay, hyperhydration (p<0.001), increased inflammation biomarkers [CRP (p<0.001)], decreased nutritional parameters: body mass cell index [BCMI (p<0.001) albumin (p<0.001)], and reduced other biomarkers [D-dimer (p=0.002)]. Multivariate analysis (Cox regression) revealed that PhA and hydration status, adjusted for age, sex, BMI, diabetes, hypertension, dyslipidaemia or heart disease, were associated (p<0.001) with increased mortality. The hazard ratio was 2.48 (95% CI, 1.60-3.84, p<0.001) for PhA and 1.12 (95% CI, 1.04 –1.20, p=0.003) for hydration percentage. PhA <3.95° was the cut-off for predicting mortality in acute COVID-19 with 93.8% sensitivity and 66.7% specificity. PhA offers greater sensitivity as a predictive prognostic test at admission, compared to the established analytical parameters of poor prognosis (CRP, lymphocytes, prealbumin). Conclusions Low PhA (<3.95°), independent of age, sex, BMI, and comorbidities, is a significant predictor of mortality risk in COVID-19. These findings suggest that the evaluation of body composition with single-frequency phase-sensitive BI measurements should be included in the routine clinical assessment of COVID-19 patients at hospital admission to identify patients at increased mortality risk.

Phase Angle as an Easy Diagnostic Tool of Meta-Inflammation for the Nutritionist

“…Due to lower fat mass and higher muscle mass percentage, PhA is known to be higher in healthy males in comparison to females. Very recently, PhA has been proposed as a useful marker of inflammation and altered hydration status in patients affected with COVID-19 [54]. In detail, Cornejo-Pareja et al reported that low PhA was a significant predictor of mortality risk in COVID-19, independent of age, sex, BMI, and comorbidities, suggesting that PhA assessment should be included in the routine clinical assessment of COVID-19 patients at increased mortality risk [54].…”

Low phase angle is associated with 60‐day mortality in critically ill patients with COVID‐19

“…Until August 2021, >209 million cases and 4.4 million deaths caused by coronavirus disease 2019 (COVID- 19) have been reported worldwide. 1 Because severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection primarily affects the respiratory system, severe illness often presents as pneumonia and acute respiratory distress syndrome requiring mechanical ventilation (MV) along with admission to intensive care units (ICUs).…”

“… 12 PhA reference values should be established according to sex, age, population, and health condition. 16 , 17 In non–critically ill patients with COVID‐19, a low PhA value was associated with disease severity and increased mortality risk; 18 , 19 however, there are not specific values that can be related to survival in critically ill patients with COVID‐19.…”

“…Mechanical ventilation, days, median (IQR)13(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) Hospital length of stay, days, median (IQR) 20(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28) 60-day all-cause mortality, n (%) 25 (37.3) Abbreviations: APACHE II, Acute Physiology and Chronic Health Evaluation II; BMI, body mass index; COVID-19, coronavirus disease 2019; IQR, interquartile range; NUTRIC, Nutrition Risk in the Critically Ill; SOFA, Sequential Organ Failure Assessment. TA B L E 2 Abbreviations: APACHE II, Acute Physiology and Chronic Health Evaluation II; ECW/TBW, extracellular water/total body water ratio; NUTRIC, Nutrition Risk in the Critically Ill; SOFA, Sequential Organ Failure Assessment; SPA, standardized phase angle.…”

“…b 30 Moonen et al performed BIA assessment in a sample of 30 non-critically ill and 24 critically ill patients with COVID-19 and reported that an increase of one unit of PhA decreased 28-day mortality (OR, 0.20; P = .02); cutoff values were not proposed. Recently, Cornejo-Pareja et al obtained a cutoff value of 3.95 • as a predictor of 90-day mortality in a sample of 127 patients; 23% required ICU admission during hospitalization 19.…”