Low Levels of Cystatin C in Patients with Acromegaly

Background: Cyst C is a cysteine protease inhibitor produced by all nucleated human cells. Studies show that Cyst C levels are associated with increased risk of cardiovascular events. Aim: We aimed to figure out Cyst C levels in acromegaly patients and to compare with control subjects who don’t have acromegaly. Methods: Forty-five subjects (24 female, 21 male, mean ages of 48.4 ± 10.3) with acromegaly and 37 gender and age matched subjects (25F, 12 M, mean ages of 50.0 ± 8.0) as control group were recruited. Acromegaly patients were classified into two groups as active acromegaly (AA, n=28) and controlled acromegaly (CA, n=17). Demographic, anthropometric and laboratory values were recorded. Framingham Coronary Heart Disease Risk Score was used to estimate risk of heart attack in 10 years. Framingham Risk Score was calculated from the web site of www.mdcalc.com/framingham-coronary-heart-disease-risk-score. Serum Cyst C levels were measured with N latex Cystatin C kit by using latex-enhanced immunonephelometry method. Results Cystatin C levels were significantly lower in the acromegaly group when compared to the control group (0.632 ± 0.174 mg/L, 0.729 ± 0.117 mg/L as mean values, respectively, p=0.005). When multiple regression analysis was performed; it was found that only age, homocysteine and GFR.cyst (s coefficient=-0.005 p<0.001, s coefficient=-0.009 p<0.001, s coefficient=0.009 p=0.001, respectvely) were independent determinants of the Cystatin C levels in the acromegaly group (R2=0.882). Conclusions: Cystatin C levels were significantly lower in the acromegaly group when compared to control group. Cystatin C levels were independently associated with homocysteine levels.