Abdominal obesity is associated with microalbuminuria and an elevated cardiovascular risk profile in patients with hypertension

Martin Thoenes^1,2, Jan-Christian Reil³, Bobby Varkey Khan⁴, Peter Bramlage¹, Massimo Volpe^5,6, Wilhelm Kirch¹,  Michael Böhm³

¹Institute for Clinical Pharmacology, Medical Faculty Carl Gustav Carus, Technical University Dresden, Germany; ²Sanofi Aventis, Global Medical Affairs, Paris, France; ³Klinik für Innere Medizin III, Kardiologie, Angiologie and Internistische Intensivmedizin, Universität des Saarlandes, Homburg, Saar, Germany; ⁴Department of Cardiology, Emory University School of Medicine, Atlanta, USA; ⁵University of Rome “Sapienza”, 2nd Faculty of Medicine, S. Andrea Hospital, Rome; ⁶IRCCS Neuromed, Pozzilli, italy

Background: Overweight and obesity are frequently associated with preventable death and have emerged as a major challenge to public health. There is an ongoing debate on the role of abdominal obesity and its value in predicting cardiovascular and renal outcomes. The present analysis evaluates the prevalence of microalbuminuria (MAU) and conventional cardiovascular risk factors in relation to measures of general and abdominal obesity.

Methods: In this multinational, observational study, 20,828 hypertensive out-patients from 26 countries including Europe, North and Latin America, Middle East, and Asia were analyzed. Urinary dipstick screening for MAU was performed as well as data on patient demographics, anthropometric measures, cardiovascular risk factors, comorbid conditions, and cardiovascular drug therapy collected. MAU prevalence was determined by a stepwise logistic regression analysis with cardiovascular risk factors as univariate.

Results: In the univariate analysis, MAU prevalence systematically increased with body mass index (BMI) from 54.4% (1st tertial) to 62.1% (3rd tertial) (p < 0.0001), an increase which was also observed for waist circumference (WC). At any level of BMI, MAU increased with WC from 53.5%, 54.8%, and 55.0% (1st tertial of WC in all three BMI tertials) to 61.4%, 62.1%, and 64.0% (3rd tertial of WC in all BMI tertials) (p < 0.0001). In the multivariate analysis, WC, but not BMI was independently associated with MAU. Furthermore, overweight/obesity were associated with the presence of modifiable and nonmodifiable risk factors.

Conclusion: An abnormal WC, but not BMI appears to be independently associated with MAU, an early marker of cardiovascular and renal risk. Increasing WC confers an incremental risk for MAU at any level of BMI, underlining the prognostic importance of abdominal fat accumulation beyond general obesity.

Keywords: obesity, abdominal, microalbuminuria, cardiovascular, renal