Benefits of Intensive Blood Pressure Control May Not Persist After Trial Intervention

The beneficial effect of intensive BP control on cardiovascular and all-cause mortality was attenuated during 4.5 years of post-trial after SPRINT.

The secondary analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) reported the beneficial effect of intensive blood pressure control on cardiovascular and all-cause mortality observed during the trial did not remain during post-trial follow-up.

The-time varying estimates of the benefit of intensive treatment for all-cause mortality were attenuated at 2.8 years following randomization, while the benefit for CVD mortality was attenuated at 5.6 years following randomization.

Outpatient blood pressure readings indicate that systolic blood pressure increased by an average of 7 mm Hg for participants randomized to intensive treatment.

“Given steadily increasing mean SBP levels in participants randomized to intensive treatment after the trial, these results suggest that maintaining more intensive BP targets throughout adulthood will likely be essential for long term CVD risk management,” wrote corresponding author Nicholas M. Pajewski, PhD, Division of Public Health Sciences, Department of Biostatistics and Data Science, Wake Forest University School of Medicine.

The findings from SPRINT suggested that intensive treatment, defined by a systolic BP (SBP) target of less than 120mg, reduced the risk of incident cardiovascular disease (CVD) and all-cause mortality, compared with treatment to an SBP target of less than 140 mm Hg. The trial length was approximately 3.3 years, meaning the longer-term effects of intensive treatment were not evaluated.

Trial participants were 50 years or older with hypertension and increased cardiovascular risk, but without diabetes or history of stroke, from 102 clinical sites in the US and Puerto Rico with the intervention taking place from 2010 to 2015.

Pajewski and colleagues evaluated the longer-term legacy effect of intensive treatment on mortality, linking SPRINT participants to the National Death Index (NDI) from 2016 to 2020. This added 4.5 years of follow-up after the conclusion of trial visits.

The trial randomized 4678 participants to the intensive treatment group (SBP, ≥120 mm Hg) compared with 4683 participants (≥140 mm Hg) in the standard treatment group. Both treatment groups had a total median follow-up time of 8.8 years. Data show a total of 818 and 826 deaths occurred among participants randomized to intensive and standard treatment, respectively.

The hazard ratio (HR) for all-cause mortality comparing treatment methods was 0.83 (95% confidence interval [CI], 0.68 - 1.01) during the trial phase and 1.08 (95% CI, 0.94 - 1.23) during the observational phase.

Over the 8.8 years of follow-up, a total of 248 and 273 CVD deaths occurred among individuals randomized to intensive and standard treatment, respectively. The HR for CVD mortality among participants randomized to intensive versus standard treatment was 0.66 (95% CI, 0.49 - 0.89) during the trial phase and 1.02 (95% CI, 0.84 - 1.24) during the observational phase.

In a subset of 2944 trial participants, the estimated mean SBP among those randomized to intensive treatment was 132.8 mm Hg (95% CI, 132.0 - 133.7) at 5 years following randomization and 140.4 mm Hg (95% CI, 137.8 - 143.0) at 10 years following randomization.

The study, “Longer-Term All-Cause and Cardiovascular Mortality with Intensive Blood Pressure Control: A Secondary Analysis of a Randomized Clinical Trial,” was published in JAMA Cardiology.