Motivation: 150?? Since medical school, we have been firmly taught that the upper limit of normal for systolic blood pressure is 140 mmHg. Recently, the panel JNC8 ruled that for adults over 60, a reasonable systolic goal is less than 150 mmHg. After having counseled countless times about the importance of blood pressure control, this increase sounded traitorous. What is the data? There have been two randomized trials addressing this issue over the past decade. I will review here the one of the larger and latest one here.
Paper: Ogihara, T, Saruta, T, Raguki, H, et. al. "Target Blood Pressure for Treatment of Isolated Systolic Hypertension in the Elderly" Hypertension (2010) 56: 196-202.
Methods: The study (VALISH) was a multicenter, prospective, randomized, open-label, blinded end point trial in Japanese adults between 70-85 years of age with isolated systolic hypertension (SBP > 160 mmHg with diastolic less than 90 mmHg). Patients were randomly treated with valsartan (titrated first with addition of second agent if necessary) into two groups: (1) Systolic blood pressure < 140 mmHg (strict control) or (2) systolic blood pressure < 150 mm Hg (moderate control). Patients were followed for minimum of two years. Primary outcome was a composite of cardiovascular events (sudden death, stroke, MI, death from cardiovascular cause, renal dysfunction).
Results:
Cohort: A total of 3260 patients were randomized. There were 181 patients lost to follow-up (95% follow-up). In total, 3079 patients were followed for average of 2.85 years. Average age was 76.1 years with 62% women. Baseline characteristics were mostly balanced between groups except there were more smokers in the strict control group vs. moderate control (21% vs. 17.4%; p = 0.01). There was history of stroke in 6.5%, ischemic heart disease in 5%, heart failure in 1.7%, and diabetes mellitus in 13%.
Blood Pressure Control: At 36 months of follow-up, the blood pressure was 13.6./74.8 in strict control group and 142/76.5 in moderate control groups. Heart rate did not differ significantly between the two groups.
Outcome: In the primary combined cardiovascular outcome, the overall rate did not differ between the groups in intention-to-treat analysis (10.6 events per 1000 patient years in strict control; 12 per 1000 patient years in moderate control group, p = 0.38). There was no difference in any of the individual components of the composite outcome. In subgroup analysis, there was not a statistical difference in patients with diabetes, dyslipidemia, and chronic kidney disease.
Adverse Effect: There was no difference in adverse effect between the two groups.
Discussion: After an average of 2.8 years of follow-up, there did not appear to be a difference in cardiovascular outcome by controlling blood pressure tighter in patients with isolated systolic hypertension. While rather remarkable and against popular medical conception, I think that the lack of longitudinal data beyond 2.8 years is cautionary is depending on these blood pressure parameters too much. This trial shows that systolic blood pressure control less than 150 mmHg versus 140 mm Hg may not make much of a difference in the short term, but what about in five to ten years? We still do not know the answer. Another problem with extending this dataset is that patients included in the cohort had low burden of disease (ischemic heart disease in only 5%). For the patient with angina, the trial may not be powered enough to detect difference in this subgroup. But then again, these arguments are probably my ingrained cognitive biases against change. The bottom line, I think, is that we need more longitudinal data before having a blood pressure parameter in mid.
Paper: Ogihara, T, Saruta, T, Raguki, H, et. al. "Target Blood Pressure for Treatment of Isolated Systolic Hypertension in the Elderly" Hypertension (2010) 56: 196-202.
Methods: The study (VALISH) was a multicenter, prospective, randomized, open-label, blinded end point trial in Japanese adults between 70-85 years of age with isolated systolic hypertension (SBP > 160 mmHg with diastolic less than 90 mmHg). Patients were randomly treated with valsartan (titrated first with addition of second agent if necessary) into two groups: (1) Systolic blood pressure < 140 mmHg (strict control) or (2) systolic blood pressure < 150 mm Hg (moderate control). Patients were followed for minimum of two years. Primary outcome was a composite of cardiovascular events (sudden death, stroke, MI, death from cardiovascular cause, renal dysfunction).
Results:
Cohort: A total of 3260 patients were randomized. There were 181 patients lost to follow-up (95% follow-up). In total, 3079 patients were followed for average of 2.85 years. Average age was 76.1 years with 62% women. Baseline characteristics were mostly balanced between groups except there were more smokers in the strict control group vs. moderate control (21% vs. 17.4%; p = 0.01). There was history of stroke in 6.5%, ischemic heart disease in 5%, heart failure in 1.7%, and diabetes mellitus in 13%.
Blood Pressure Control: At 36 months of follow-up, the blood pressure was 13.6./74.8 in strict control group and 142/76.5 in moderate control groups. Heart rate did not differ significantly between the two groups.
Outcome: In the primary combined cardiovascular outcome, the overall rate did not differ between the groups in intention-to-treat analysis (10.6 events per 1000 patient years in strict control; 12 per 1000 patient years in moderate control group, p = 0.38). There was no difference in any of the individual components of the composite outcome. In subgroup analysis, there was not a statistical difference in patients with diabetes, dyslipidemia, and chronic kidney disease.
Adverse Effect: There was no difference in adverse effect between the two groups.
Discussion: After an average of 2.8 years of follow-up, there did not appear to be a difference in cardiovascular outcome by controlling blood pressure tighter in patients with isolated systolic hypertension. While rather remarkable and against popular medical conception, I think that the lack of longitudinal data beyond 2.8 years is cautionary is depending on these blood pressure parameters too much. This trial shows that systolic blood pressure control less than 150 mmHg versus 140 mm Hg may not make much of a difference in the short term, but what about in five to ten years? We still do not know the answer. Another problem with extending this dataset is that patients included in the cohort had low burden of disease (ischemic heart disease in only 5%). For the patient with angina, the trial may not be powered enough to detect difference in this subgroup. But then again, these arguments are probably my ingrained cognitive biases against change. The bottom line, I think, is that we need more longitudinal data before having a blood pressure parameter in mid.
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