Phase angle predicts survival in hemodialysis patients

Chertow, Glenn M; Jacobs, Danny O; Lazarus, J.Michael; Lew, Nancy L; Lowrie, Edmund G

« Previous Next »Journal of Renal Nutrition
Volume 7, Issue 4 , Pages 204-207, October 1997

Phase angle predicts survival in hemodialysis patients☆

Glenn M Chertow, MD, MPH
- Address reprint requests to Glenn M. Chertow, MD, MPH, Dialysis Unit Administrative Office, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Metabolic Support Service, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Fresenius Medical Care-NA, Lexington, MA, USA.
Danny O Jacobs, MD, MPH
- Metabolic Support Service, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Fresenius Medical Care-NA, Lexington, MA, USA.
J.Michael Lazarus, MD
- Metabolic Support Service, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Fresenius Medical Care-NA, Lexington, MA, USA.
Nancy L Lew, SM
- Metabolic Support Service, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Fresenius Medical Care-NA, Lexington, MA, USA.
Edmund G Lowrie, MD
- Metabolic Support Service, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Fresenius Medical Care-NA, Lexington, MA, USA.

Abstract

Objective: To determine the relation between phase angle by bioelectrical impedance analysis (BIA) and survival in hemodialysis patients.

Design: Cohort analytic study.

Setting: One hundred one free-standing outpatient dialysis units.

Patients: Three thousand nine adult patients on thrice weekly hemodialysis. Patients with amputations above the transmetatarsal site were excluded from participation.

Main Outcome Measure: Vital status, with follow-up to at least 1 year.

Results: Mean phase angle was 4.8 ± 1.8 degrees. Patients with narrow (low) phase angle experienced an increased relative risk (RR) of death (<3 degrees; RR 4.3; 95% confidence interval [Cl], 2.9–6.2; and 3 to 4 degrees); RR 2.2; 95% Cl, 1.6–3.2; compared with the ≥6 degrees reference). There were no significant differences in risk among patients with phase angle 4 to 5 degrees (RR 1.2; 95% Cl, 0.8–1.8), 5 to 6 degress (RR 1.1; 95% Cl, 0.7–1.7), and ≥6 degrees, suggesting a nonlinear relation between phase angle and survival. The RRs for phase angle <4 degrees remained statistically significant after adjusting for age, gender, race, serum albumin and creatinine concentrations, and dialysis intensity (<3 degrees, RR 2.2; 95% Cl, 1.6–3.1, and 3 to 4 degrees, RR 1.3; 95% Cl, 1.0–1.7, compared with all patients ≥4 degrees).

Conclusions: In patients on hemodialysis, BIA-derived phase angle <4 degrees was associated with an increased RR of death, even after adjustment for case mix and several nutritional indicators. Further research is required to determine whether BIA can be used to monitor health status over time, or to gauge response to nutrition support or other clinical interventions in patients with end-stage renal disease.

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