The Modification of Diet in Renal Disease 4-calculated glomerular filtration rate is a better prognostic factor of cardiovascular events than classical cardiovascular risk factors in patients with peripheral arterial disease

Abstract

Objective: Risk prediction is important in medical management, especially to optimize patient management before surgical intervention. No quantitative risk scores or predictors are available for patients with peripheral arterial disease (PAD). Surgical risk and prognosis are usually based on anesthetic scores or clinical evaluation. We suggest that renal function is a better predictor of risk than other cardiovascular parameters. This study used the four-variable Modification of Diet in Renal Disease (MDRD-4)-calculated glomerular filtration rate (GFR) to compare classical cardiovascular risk factors with prognosis and cardiovascular events of hospitalized PAD patients.

Methods: The study evaluated 204 patients who were admitted for vascular intervention and diagnosed with grade IIb, III, or IV PAD or with carotid or renal stenosis. Those with carotid or renal stenosis were excluded, leaving 188 patients who were randomized from 2004 to 2005 and monitored until 2010. We performed a life-table analysis with a 6-year follow-up period and one final checkpoint. The following risk factors were evaluated: age, sex, ischemic heart disease, ictus (as a manifestation of cerebrovascular disease related to systemic arterial disease), diabetes, arterial hypertension, dyslipidemia, smoking, chronic obstructive pulmonary disease, type of vascular intervention, and urea and creatinine plasma levels. The GFR was calculated using the MDRD-4 equation. Death, major cardiovascular events, and reintervention for arterial disease were recorded during the follow-up.

Results: Patients (73% men) were a mean age of 71.38 ± 11.43 (standard deviation) years. PAD grade IIb was diagnosed in 41 (20%) and grade III-IV in 147 (72%). Forty-two minor amputations (20.6%), 21 major amputations (10.3%), and 102 revascularizations (50%) were performed. A major cardiovascular event occurred in 60 patients (29.4%), and 71 (34.8%) died. Multivariate logistic regression analysis showed that the MDRD-4 GFR, age, and male sex were independent variables related to death and that the MDRD-4 GFR and chronic obstructive pulmonary disease were related to major cardiovascular events. A statistically significant relationship was also found between serum creatinine levels and reintervention rates.

Conclusions: The MDRD-4 GFR was a better predictor of risk of death or infarction than classical cardiovascular risk factors in patients with PAD. This suggests that its routine use in the initial evaluation in patients with PAD is beneficial.