Endocrine Abstracts

Background and aims: Subjects with primary (PAI) and secondary adrenal insufficiency (SAI)/hypopituitarism have an increased cardiovascular mortality for reasons that are unclear. Arterial stiffness is an independent risk factor for increased cardiovascular mortality. We sought to measure arterial stiffness in subjects with AI and aimed to identify which factors might account for any increase observed.

Methods: Ethical approval was obtained for this study of 40 subjects with AI free of known cardiovascular disease (20 PAI; 20 SAI, panhypopituitary on full hormone replacement). Arterial stiffness (augmentation index, brachial/aortic pulse wave velocity (b/aPWV)) was measured by the Sphygmocor system.

Results: There were more females in the PAI group (70 vs 40%) but mean age (48.2 vs 47.35 years), duration of disease (17, 13 years) and percentage of smokers (25, 15%) was not different between groups. Subjects with SAI had greater central obesity (waist circumference (wc) 107 vs 95 cm; P<0.01) and high sensitivity CRP but similar blood pressure despite marginally lower mean doses of hydrocortisone (21 vs 24 mg). bPWV and augmentation index were greater, however, in the PAI group (P<0.01). There was a high prevalence of the metabolic syndrome in the group as a whole (50%) but this was more pronounced in the SAI group (65 vs 35%, P=0.05). There was a strong positive correlation of wc with insulin resistance (HOMA-IR; P=0.03) and CRP (P=0.001) but not with hydrocortisone dose, disease duration, lipid status or any measures of arterial stiffness. Whole group arterial stiffness was higher than reference data and increased markedly with age (aPWV P<0.001) and total cholesterol concentration (P=0.002).

Conclusions: Cardiometabolic risk may be increased in subjects with primary and secondary AI, even when hormone replacement is optimal. Total cholesterol concentration is the single most important modifiable risk factor for increased arterial stiffness in these groups.