In patients with prior stroke and hypertension, lower BP target no more effective in preventing recurrent strokes (RESPECT)

Reference

Kitagawa K, Yamamoto Y, Arima H, et al, for the Recurrent Stroke Prevention Clinical Outcome (RESPECT) Study Group. Effect of standard vs intensive blood pressure control on the risk of recurrent stroke: a randomized clinical trial and meta-analysis. JAMA Neurol 2019;76(11):1309-1318.

Synopsis

The controversial SPRINT trial excluded patients with diabetes or those with a previous stroke, so these researchers recruited patients from hospitals in Japan who had hypertension and a stroke within the 3 years prior to study enrollment. The patients had to be between 50 and 85 years of age, be independent in ambulation, and have systolic blood pressure of 130 to 180 mm Hg or diastolic blood pressure of 80 to 110 mm Hg while taking a regimen of 0 to 3 antihypertensive medications. The authors randomly assigned the patients to a "standard" treatment target of 140/90 (n = 630) or to an intensive treatment target of 120/80 or lower (n = 633). If the patients had diabetes, chronic kidney disease, or a previous myocardial infarction, the standard treatment target was less than 130/80. To achieve the blood pressure targets, the researchers used angiotensin receptor blockers, thiazides, amlodipine, and spironolactone in a stepwise fashion every 4 weeks. After an average follow-up of nearly 4 years, the study was stopped due to slow recruitment and a cessation of funding. (Huh. I thought drug companies had limitless resources to prove things that benefit their bottom line). At the end of the study, the annual rate of first subsequent stroke was 2.3% in the standard treatment group and 1.6% in the intensive treatment group, but this was not statistically significant. Approximately 2% of the patients in each group stopped taking any antihypertensive medications. The target blood pressure was achieved in 62% of the standard treatment patients compared with 32% of the intensively treated patients. The original study plan was to enroll 5000 patients, but partway through the study the authors used their existing outcome data to re-estimate their sample size needs and determined they would need 2000 to detect a 30% relative reduction in recurrent strokes in the intensively treated patients. In addition to the randomized trial, the authors give a very cursory description of pooling their study data in a meta-analysis of 3 additional similar studies. This is not a bad idea. Pooling data from underpowered studies allows us to find potentially important tools. However, since the description of the meta-analysis does not provide great confidence in their findings, I would defer until a rigorously conducted meta-analysis takes place.