Survival Analysis According to the Standardized Phase Angle Measured By Bioimpedanciometry to Estimate Body Composition in Patients with Hematological Malignancies during Nutritional Screening at Hospital Admission

Rationale

Much work has been done to create prognostic score in patients with Leukemia, Lymphoma or Myeloma. Bioimpedanciometry is a method to estimate body composition and cell membrane integrity, through the Phase Angle (PhA). Vector electrical bioimpedance allows direct measurement of electrical impedance determined by the vector relationship between resistance (Rz), which represents the hydration state, and reactance (Xc), which is related to the integrity of cell membranes. The angle formed by both vectors is the phase angle (PhA) and is considered a global prognostic factor that informs on cellular functionalism in relation to body composition. Multiple studies have related the value of PhA with nutritional status and prognosis in different pathologies and clinical situations, with lower PhA values being indicative of greater morbidity and mortality in all of them. The biological factors that most affect PhA are age, sex and Body Mass Index (BMI), so we consider the Standardized Phase Angle (SPhA), determined according to these variables.

The objective of the study is to establish SPhA cut-off points to predict mortality and survival in hospitalized hematological patients.

Methods

Retrospective study in hematological patients admitted for any reason at the Hospital QuirónSalud Málaga in two years (2019-2021). A complete nutritional assessment was performed, including bioimpedance measurement, with the PhA and SPhA measure.

Results

121 patients analyzed, 66 (54.5%) women, with a mean age of 63.5±15.1 years.

69 patients with lymphoma (57.5%), 27 with leukemia (22.5%), 20 with myeloma (16.7%) and 4 with amyloidosis (3.3%). The mean PhA was 5.1º in men and 4.1º in women. There is no significant difference in PhA according to the disease. The mean SPhA was -1.1 (minimum -4.6 maximum 3.8).

The mortality was 37.2% (45 patients).

Cox regression for survival analysis set the cut-off point to -1.7. When the SPhA is >-1.7, the probability of survival at 12 months is 89% (74-100%, 95% CI), against 56% (46-68%, 95% CI) if it were <-1.7.

Conclusions The Standardized Phase Angle is a useful tool to complement nutritional, non-invasive, sensitive and specific assessment that allows predicting mortality in hospitalized hematological patients.

Rules

The study has been approved by the Ethics Committee of the Regional Hospital of Malaga (2758-N-21).

Cordoba:Roche: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Lilly: Consultancy; BeiGene: Consultancy; Janssen: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy; GenMab: Consultancy; Takeda: Consultancy; Kite: Consultancy, Speakers Bureau; Pfizer: Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Honoraria; Gilead: Honoraria.