Physicians' Academy for Cardiovascular Education

Comparison of SPRINT results with the US general population treated for hypertension

Egan BM et al., Hypertension 2016

Systolic Blood Pressure Intervention Trial (SPRINT) and Target Systolic Blood Pressure in Future Hypertension Guidelines


Egan BM, Li J, Wagner CS
Hypertension 2016 Aug;68(2):318-23
 

Background

Based on data of the systolic blood pressure (SBP) intervention trial (SPRINT) it was concluded that an SBP target <120 mmHg resulted in more reduction of major cardiovascular (CV) events and mortality compared to when a target of <140 mmHg was used [1]. This raised the question whether future guidelines should consider lowering the SBP goal to below 130 or 120 mmHg.  
 
In the SPRINT trial, intensive treatment (SBP target <120 mmHg) was compared to standard treatment (SBP target <140 mmHg). However, two things should be taken into account when interpreting the results of the SPRINT study:
  • It was assumed that the standard-arm of treatment resulted in SBP values as low or lower than the SBP of US adults with treated hypertension. If this is not the case, the results of the intensive treatment could be overestimated.
  • It was assumed that intensive treatment resulted in a lower mean SBP than in US adults with treated hypertension and an SBP lower than 140 mmHg. If this is not the case, the rationale of lowering the target would be less compelling.
To clear these 2 points of criticism, Egan and coworkers evaluated these using the National health and nutrition examination survey (NHANES) data. Mean SBP was compared in3 NHANES groups: a SPRINT-like group that would fulfil the SPRINT inclusion criteria, all adults ≥18 years and all adults ≥18 years but excluding the SPRINT-like group and others with SPRINT exclusion criteria. Secondly, mean SBP in these 3 groups with treated hypertension and SBP<140 was compared with the mean SBP in the SPRINT intensive treatment group.
 

Main results

  • 2882 US patients were ≥18 years and treated for hypertension. 684 of these patients fit into the SPRINT-like group and 741 patients were adults excluding the SPRINT-like group and other SPRINT exclusion criteria.
  • The mean SBP attained in SPRINT-like adults was 133.0 mmHg, which is lower than the mean attained using standard therapy in the SPRINT trial (134.6 mmHg during 3.26 yrs trial). The mean SBP attained in all adults was 130.1 and in all adults excluding SPRINT-like patients 124.6 mmHg.
  • SBP control to <140 mmHg was highest in the subset excluding SPRINT-like participants (81.9%) and lowest in SPRINT-like participants (66.2%), and was intermediate in all treated adults (72.2%).
  • Of the SPRINT-like patients that achieved an SBP <140 mmHg, 68.3% also had an SBP <130. Of the adults excluding SPRINT-like patients, 83.4% had an SBP below 130 mmHg.
 

Conclusion

As SPRINT-like US adults attained as low or lower SBP values compared to SPRINT standard therapy patients, SPRINT intensive therapy results could be overestimated. The difference was probably even larger when corrected for the different BP outcomes between conventional BP measurements and the automated measurement used in the SPRINT trial.
 
Furthermore, US adults with treated hypertension and SBP <140 have mean SBP values similar to that in SPRINT intensive treatment. This weakens the rationale of lowering the SBP target.
 
According to SPRINT standard treatment, antihypertensive treatment was reduced when SBP was below certain levels. However, SPRINT standard treatment contributed to higher values than in US adults with treated hypertension. Therefore, SPRINT results indicate that the large proportion of adults with SBP <140 mmHg who also achieve SBP <130 are benefiting and should not have treatment withdrawn.
 
Find this publication online at Hypertension
 

References

1. The SPRINT research group. A randomized trial of intensive versus standard blood-pressure control. N. Engl. J. Med. 2015;373:2103-2116