 9. Sample size calculation: Sample size was calculated using Stata version 12. A sample size of 90 45 in each group achieves 80 power to detect 5 mmHg difference in systolic BP change from baseline to end of follow-up in intervention group compared to usual care group, with an estimated standard deviation SD of 9.5, significance level of 0.05 using a two-sided two-sample t-test. Assuming that there could be 10 drop out rate, we plan to take the total sample size of 100 subjects. At least 152 eligible subjects 72 in each group would be necessary to attain at least 66 recruitment rate. 