Bioelectrical impedance phase angle as a prognostic marker in chronic heart failure.

OBJECTIVE

The main purpose of the present study was to assess the prognostic value of the bioelectrical phase angle (PA) in patients with heart failure independently of other parameters of a poor prognosis.

METHODS

This retrospective study included 389 patients with heart failure. Anthropometric, body composition, clinical, biochemical, and echocardiographic data were collected from all patients. The quartiles were obtained for the PA, and patients were classified according to the quartiles into four groups. The endpoint was all-cause mortality. A Cox proportional hazards regression analysis was performed to estimate the adjusted relative risks, and 95% confidence intervals were obtained for the potential predictors of death.

RESULTS

Patients below the lowest quartile of PA (<4.2°) had decreased mean body mass index, handgrip strength, and hemoglobin values and a larger proportion of patients in New York Heart Association functional class III and renal failure. The Kaplan-Meier survival analysis among PA groups showed a better survival for patients above the highest quartile of PA (≥5.7°), and survival decreased as the PA decreased. The Cox regression analysis found that a PA <4.2 was an independent predictor of mortality (relative risk 3.08, 95% confidence interval 1.06-8.99), adjusting for age, hemoglobin levels, and diabetes, compared with a PA ≥5.7.

CONCLUSION

In this study population, a smaller PA was associated with malnutrition markers such as decreased body mass index, handgrip strength, and hemoglobin values and with a poor New York Heart Association functional class and renal failure. Adjusting for age, hemoglobin levels, and diabetes, a PA <4.2 was found to be an independent predictor of all-cause mortality in chronic heart failure.