Cardiometabolic risk parameters in "non-functioning" adrenal incidentalomas: a systematic review and meta-analysis

Objective: Several studies have investigated whether patients with non-functioning adrenal incidentalomas (NFAI) have an increased cardiometabolic risk, based on surrogate parameters such as the augmentation index (Aix), carotid intima-media thickness (cIMT), flow mediated dilation (FMD), insulin resistance (IR), left ventricular mass index (LVMI) and pulse wave velocity (PWV), as compared to patients without adrenal incidentalomas (AI). We sought to analyse the available literature to evaluate AIx, cIMT, FMD, IR, LVMI and PWV in patients with NFAI as compared to patients without AI. Design: Systematic review and meta-analysis. Methods: We included studies that evaluated the cIMT and IR (primary outcomes) and AIx, FMD, LVMI and PWV (secondary outcomes) in patients with NFAI versus matched subjects without AI. A random-effects model (DerSimonian and Laird) was used to calculate the standardized mean difference (SMD) and 95% Confidence Interval (95%CI) for each outcome. Results: Among the 24 available studies, 21 studies provided the necessary data (2228 subjects, mean age 53.3±2.9 years, 35% males). Data on cIMT, IR, AIx, FMD, LVMI and PWV were reported in 12 (1063 subjects), 15 (1745 subjects), 2 (140 subjects), 3 (198 subjects), 3 (201 subjects) and 2 (140 subjects) studies, respectively. As compared with patients without AI, patients with NFAI showed statistically significant differences in cIMT, IR, AIx, FMD, LVMI, PWV (SMD and 95%Confidence Interval: 1.22, 0.87-1.58; 0.51, 0.32-0.69; 0.94, 0.38-1.50; -1.24, -1.84- -0.65; 0.41, 0.04-0.78; 1.03, 0.16-1.89, respectively). Conclusions: Based on cIMT, IR, AIx, FMD, LVMI and PWV levels, patients with NFAI may be at increased cardiovascular risk.