Chronic kidney disease in hypertensive patients: results of the Belgica-Stroke study

Background: Although chronic kidney disease (CKD) is associated with poor cardiovascular (CV) outcome, reduced glomerular filtration rate (GFR) is not used in CV risk prediction. Objective: The primary objective of the BELGICA-STROKE study was to evaluate the impact of online risk calculation on estimated 10-year Framingham stroke (FSR) and CV mortality risk (SCORE) up to 1 year after its implementation. This subanalysis assessed the relation between CKD and both estimated risks. Design and Methods: Prospective multicenter study in primary care. Hypertensive patients >40 years with uncontrolled BP (>140/>90 mmHg and >130/>80 mmHg if diabetes). FSR was calculated for patients without a history of stroke, SCORE for patients without a previous atherosclerotic event or diabetes. CKD was defined as estimated GFR<60 ml/min/m2 (Cockcroft&Gault equation). Results: Of 15744 patients, recruited by 877 physicians, 6 % had reduced GFR. Hypertensive patients with CKD were significantly older (73 ± 11 vs 66 ± 11yrs), had lower diastolic BP (89 ± 10 vs 88 ± 10mmHg), more frequently diabetes (51 vs 24%), left ventricular hypertrophy (57 vs 16%), and atrial fibrillation (13 vs 6%). More patients were male (56 vs 52%) and ex-smokers (29 vs 23%). Total, HDL and LDL cholesterol were significantly lower. Coronary heart disease, heart failure, cerebrovascular and peripheral arterial disease were significantly more prevalent. Median estimated GFR was resp. 80 and 93 ml/min/m2 among FSR and SCORE patients (p < 0.001). The prevalence of reduced GFR was twice as high among FSR as among SCORE patients (24% vs 10%). Median FSR and SCORE were significantly higher in patients with CKD (resp. 27 vs 15 and 6 vs 4). Increasing FSR and SCORE categories were associated with decreasing GFR, with the largest decrease seen among FSR patients. Significantly more CKD patients were treated with antihypertensive combination therapy (82 vs 62%) and lipid lowering drugs (63 vs 43%). Conclusion: Hypertensive patients with uncontrolled BP and reduced kidney function have a higher prevalence of concomitant CV disease and a higher FSR and SCORE risk than their counterparts without CKD.