Cystatin C and preeclampsia: a case control study

Pregnancy increases plasma cystatin C, but levels are much higher in preeclampsia. Previous studies have not quantified preeclampsia risk with varying cystatin C concentrations or adjusted for confounders. We performed a case-control study of 100 preeclampsia cases and 100 random pregnancies uncomplicated by hypertension (controls). All women were free of pre-existing hypertension, diabetes, and renal disease, and gave birth to singletons. Plasma cystatin C was measured at delivery. Adjusted odds ratios (OR) and 95% confidence intervals (CI) of preeclampsia by quartiles (based on control distribution) of maternal plasma cystatin C were estimated using multivariable logistic regression models. Mean cystatin C levels were elevated in preeclampsia cases compared with controls (1.38 +/- 0.04 vs. 1.22 +/- 0.03 mg/L, p < 0.01). Compared to the first quartile, the estimated risk of preeclampsia was increased by approximately 12-fold for the fourth quartile, after adjusting for maternal age, body mass index, physical inactivity, smoking, and gestational age. Increased plasma levels of cystatin C were independently associated with preeclampsia. Further studies are required to assess the role of cystatin C levels in preeclampsia severity and maternal and fetal outcomes.