Visceral adiposity index is associated with insulin sensitivity and adipocytokine levels in newly diagnosed acromegalic patients.

CONTEXT

The visceral adiposity index (VAI) has proved to be a marker of visceral adipose dysfunction, strongly associated with insulin sensitivity in both the general and specific populations of patients at metabolic risk.

OBJECTIVE

The objective of the study was to test VAI as a useful tool to assess early metabolic risk in acromegaly.

PATIENTS

Twenty-four newly diagnosed acromegalic patients (11 women and 13 men, aged 54.9 ± 13.6 yr) were grouped into those with normal (group A, n = 13, 54.2%) and those with high VAI (group B, n = 11, 45.8%).

OUTCOME MEASURES

Glucose, hemoglobin A1c, nadir and area under the curve (AUC) of GH (AUC(GH)) during the oral glucose tolerance test, AUC(Cpeptide) during a mixed-meal tolerance test, M value during euglycemic-hyperinsulinemic clamp, oral dispositional index (DIo), each component of the metabolic syndrome, leptin, adiponectin, TNF-α, and IL-6.

RESULTS

The VAI value was positively correlated with the age of patients (ρ = 0.408; P = 0.048), tumor volume (ρ = 0.638; P = 0.001), basal GH (ρ = 0.622; P = 0.001), nadir GH (ρ = 0.534; P = 0.007), AUC(GH) (ρ = 0.603; P = 0.002), IGF-I (ρ = 0.618; P = 0.001), TNF-α (ρ = 0.512; P = 0.010), and AUC(Cpeptide) (ρ = 0.715; p<0.001) and negatively with adiponectin (ρ = -0.766; P < 0.001), M value (ρ = -0.818; P < 0.001), and DIo (ρ = -0.512; P = 0.011). Patients with high VAI showed significantly higher basal GH levels (P = 0.018), AUC(GH) (P = 0.047), IGF-I (P = 0.047), AUC(Cpeptide) (P = 0.018), lower M value (P < 0.001), DIo (P = 0.006), and adiponectin levels (P < 0.001), despite the absence of a significantly higher prevalence in the overt metabolic syndrome and glucose tolerance abnormalities. AUC(GH) proved to be the main independent factor influencing VAI.

CONCLUSIONS

In acromegaly, VAI appears to be associated with disease activity, adiponectin levels, and insulin sensitivity and secretion and is influenced independently by GH levels. VAI could therefore be used as an easy and useful new tool in daily clinical practice for the assessment of early metabolic risk associated with active acromegaly.