Source: Cardiology  |  Posted 7 years ago

Mildly decreased creatinine clearance is a marker of preclinical cardiac and vascular damage in hypertensive patients with normal serum creatinine, Italian researchers report.

Mild renal dysfunction is a powerful, independent predictor of cardiovascular events in patients with primary hypertension. An association between decreased creatinine clearance and hypertensive end-organ damage is of interest, because it may help explain the high morbidity and mortality in patients with mild renal dysfunction, according to Giovanna Leoncini and colleagues of the Department of Internal Medicine, University of Genoa.

The research team studied 957 middle-aged patients with untreated primary hypertension and normal serum creatinine to evaluate the relationship between creatinine clearance and early signs of target organ damage.

In addition to standard blood chemistry evaluations, measurements were obtained for creatinine clearance (estimated by the Cockcroft-Gault equation), left ventricular hypertrophy (LVH, determined by electrocardiography), and retinal vascular changes (determined by direct ophthalmoscopy).

Analysis of the clinical characteristics of study patients revealed a mean creatinine clearance of 83?21.2 mL/min, and a prevalence of 13% for LVH and 49% for retinopathy.

Furthermore, univariate correlation showed an inverse relationship of creatinine clearance with disease duration (r = -0.132, []P[] < .0001), systolic blood pressure (r = -.110, []P[] = .001), serum glucose (r = -.090, []P[] = .007), total cholesterol (r = -.196, []P[] < .0001), and low-density lipoprotein cholesterol (r = -.196, []P[] < .0001).

In the lower quintile of creatinine clearance, patients had significantly worse risk profiles (including older age, higher SBP, longer disease duration, and higher total cholesterol) and a higher prevalence of LVH ([]P[] = .04) and retinal vascular changes ([]P[] = .02). Independent of traditional cardiovascular risk factors, each standard deviation reduction in creatinine clearance was associated with a 20% increase in risk of cardiac or retinal abnormalities.

"Although our study does not directly assess the usefulness of creatinine clearance in identifying patients at cardiovascular risk, we suggest that due to the ready availability and low cost, this test should be routinely performed not only to assess renal function but also to obtain a more sensitive evaluation of cardiovascular damage in hypertensive patients," the investigators concluded.