A 24-Hour Comparison of Serum Growth Hormone Concentrations in Patients with Heart Failure versus Healthy Controls.

This study compares endogenous serum growth hormone concentrations over a 24-hour period in patients with chronic heart failure (CHF) and matched controls. Design: Prospective, 24-hour, endogenous concentration comparison. Setting: Hospital research center. Patients: Eight evaluable patients with nonischemic dilated cardiomyopathy and 10 healthy control subjects, matched for age and sex. Intervention: Over a 24-hour period, blood was drawn from the study participants every 20 minutes for determination of growth hormone. Measurements and Main Results: For each patient, the area under the concentration-time curve from time 0-24 hours (AUC[sub0-24]), maximum concentration (C[submax]), and minimum concentration (C[subnadir]) of growth hormone were determined. The AUC[sub0-24] and C[submax] were 74% (p<0.05) and 62% (p<0.05) lower in patients with CHF than in controls, respectively. The C[subnadir] for all participants was 0 μg/L. Variability in growth hormone concentrations over the 24 hours was considerable for all study participants. Conclusions: Growth hormone concentrations are suppressed over a 24-hour period in patients with CHF versus healthy controls. Variability in levels throughout the day suggests that a single point evaluation cannot be used to determine deficiency or abundance of growth hormone. [ABSTRACT FROM AUTHOR]