Phase angle and COVID-19: A systematic review with meta-analysis.

Phase angle (PhA) has been identified as a poor prognostic factor in patients with COVID-19. This study aimed to achieve a systematic review, where we discussed the potential role of PhA value as a prognostic marker of adverse clinical outcomes such as mortality and complication in hospitalized with SARS-CoV2 infection and established the strength of recommendations for use. A systematic literature review with meta-analysis was done in the main electronic databases from 2020 to January 2023. The selected articles had to investigate adverse consequences of the COVID-19 population and raw bioimpedance parameters such as PhA and published in peer-reviewed journals. GRADE tools regarded the quality of the methodology. The review protocol was registered in PROSPERO. Only eight studies, 483 studies, were eligible for the analysis. In general, differences in PhA were seen between the comparative study groups. Patients with a low PhA experienced poor outcomes. A low PhA was associated with a significantly increased mortality risk [RR: 2.44; 95% CI (1.20-4.99), p = 0.01; I2 = 79% (p = 0.0008)] and higher complications risk [OR: 3.47, 95% CI (1.16 - 10.37), p = 0.03; I2 = 82% (p = 0.004)] in COVID-19 patients. Our analysis showed four evidence-based recommendations on the prognostic value of PhA with two strong recommendations, one of moderate and another of low-moderate quality, for predicting mortality and complications, respectively. We recommend using PhA as a prognostic marker for mortality and complications in this population. Although the results are promising, future studies must identify the PhA cut-off to guide therapeutic decisions more precisely.Registration code in PROSPERO: CRD42023391044.

Overhydration Assessed Using Bioelectrical Impedance Vector Analysis Adversely Affects 90-Day Clinical Outcome among SARS-CoV2 Patients: A New Approach.

BACKGROUND: COVID-19 has taken on pandemic proportions with growing interest in prognostic factors. Overhydration is a risk factor for mortality in several medical conditions with its role in COVID-19, assessed with bioelectrical impedance (BI), gaining research interest. COVID-19 affects hydration status. The aim was to determine the hydration predictive role on 90 d survival COVID-19 and to compare BI assessments with traditional measures of hydration. METHODS: We studied 127 consecutive COVID-19 patients. Hydration status was estimated using a 50 kHz phase-sensitive BI and estimated, compared with clinical scores and laboratory markers to predict mortality. RESULTS: Non-surviving COVID-19 patients had significantly higher hydration 85.2% (76.9-89.3) vs. 73.7% (73.2-82.1) and extracellular water/total body water (ECW/TBW) 0.67 (0.59-0.75) vs. 0.54 (0.48-0.61) (p = 0.001, respectively), compared to surviving. Patients in the highest hydration tertile had increased mortality (p = 0.012), Intensive Care Unit (ICU) admission (p = 0.027), COVID-19 SEIMC score (p = 0.003), and inflammation biomarkers [CRP/prealbumin (p = 0.011)]. Multivariate analysis revealed that hydration status was associated with increased mortality. HR was 2.967 (95%CI, 1.459-6.032, p < 0.001) for hydration and 2.528 (95%CI, 1.664-3.843, p < 0.001) for ECW/TBW, which were significantly greater than traditional measures: CRP/prealbumin 3.057(95%CI, 0.906-10.308, p = 0.072) or BUN/creatinine 1.861 (95%CI, 1.375-2.520, p < 0.001). Hydration > 76.15% or ECW/TBW > 0.58 were the cut-off values predicting COVID-19 mortality with 81.3% and 93.8% sensitivity and 64 and 67.6% specificity, respectively. Hydration status offers a sensitive and specific prognostic test at admission, compared to established poor prognosis parameters. CONCLUSIONS AND RELEVANCE: Overhydration, indicated as high hydration (>76.15%) and ECW/TBW (>0.58), were significant predictors of COVID-19 mortality. These findings suggest that hydration evaluation with 50 kHz phase-sensitive BI measurements should be routinely included in the clinical assessment of COVID-19 patients at hospital admission, to identify increased mortality risk patients and assist medical care.

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.

BACKGROUND & 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.