Multiple imputation for missing values gave similar results : the mean baseline was 143.5 / 80.2 mm Hg in the intervention group vs 144.2 / 79.9 mm Hg in the control group , and at 12 months , the mean was 128.6 / 73.6 mm Hg in the intervention group vs 138.2 / 76.4 mm Hg in the control group , with a difference of 8.8 mm Hg ( 95 % CI , 4.9-12 .7 ) for systolic and 3.1 mm Hg ( 95 % CI , 0.7-5 .5 ) for diastolic blood pressure between groups .