Author/Editor		Bajuk-Studen, Katica; Barkan, Ariel
Title		Assessment of the magnitude of growth hormone hypersecretion in active acromegaly: reliability of different sampling models
Type		članek
Source		J Clin Endocrinol Metab
Vol. and No.		Letnik 93, št. 2
Publication year		2008
Volume		str. 491-6
Language		eng
Abstract		Context: The pulsatility of GH secretion in acromegaly poses difficulty in ascertaining true daily GH milieu in patients with this disease. Intensive GH sampling (every 10-20 (Q10-20) min for 24 h) is not practical in clinical practice. Objective: Our objective was to ascertain reliability of abbreviatedsampling protocols to reflect true 24-h mean GH concentrations in patients with acromegaly. Design: An analysis of previously obtained plasma GHprofiles was performed. Setting: The analysis was performed at the General Clinical Research Center at the University of Michigan. Patients: A total of 115 GH profiles obtained in 94 patients with active acromegaly were examined. InterventionČ Frequent blood sampling, i.e. Q10-20 min for 24 h, was performed. Main Outcome Measures: Concordance of 24-h mean GH concentrations derived from Q10- to 20-min samplings with abbreviated GH sampling schedules was performed. The study was planned after data collection. Results: All abbreviated schedules of GH sampling correlated well with the true 24-h plasmaGH means (i.e. Q10- to 20-min sampling) (R = 0.93-0.98; P < 0.0001 for all). In the GH range more than 20 mugžliter, only 5 and 9-h means had R values more than 0.9. Single GH concentrations less than 1 mugžliter had a positive predictive value of only 0.29, and those with less than 2.5 mugžliterhad a positive predictive value of 0.67 vs. their corresponding 24-h mean GH values of the same magnitude. Conclusions: The intensity of GH sampling in patients with acromegaly may vary depending on the nature of the required information. Investigators and clinicians should be aware of the limitations of the abbreviated GH sampling protocols in acromegaly.
Descriptors		ACROMEGALY SOMATOTROPIN CIRCADIAN RHYTHM