Significant independent predictors of mortality at study entry were age , diabetes mellitus , history of hypertension , systolic blood pressure ( hazard ratio [ HR ] , 1.3 per 20 mm Hg increase ) , serum hemoglobin < 13 g/dL ( HR , 1.6 ) , renal function ( HR , 1.3 per estimated glomerular filtration rate decrease of 20 mL/min ) , and body mass index ( HR , 1.8 per 10 kg/m2 decrease ) .