I am happy to finally see a research article, SPRINT 75 looking specifically on the optimal blood pressure target for the elderly population. We have debated for years if we need to keep the blood pressure low, or whether we should let it run higher for fear of adverse effects such as increased risk of falls, chronic kidney disease and electrolyte imbalances. The evidence from HYVET trial which enrolled patients over the age of 80 demonstrated both reduced stroke and all-cause mortality by targeting their blood pressure to 150/80mmHg.  But we don’t know if there would any added benefits by aiming for a much lower blood pressure targets until now.

The pros and cons of SPRINT 75  was recently discussed in this podcast.  Here are some highlights of the SPRINT 75:

  • The study evaluated the effects of intensive (<120mmHg) compared with standard (<140mmHg) SBP targets in persons aged 75 years or older with hypertension but without diabetes.
    • Intensive treatment group n = 1317
    • Standard treatment group n = 1319
  • Primary outcome was a composite of non-fatal myocardial infarction, acute coronary syndrome not resulting in a myocardial infarction, nonfatal stroke, nonfatal acute decompensated heart failure and death from cardiovascular causes.
  • At a median follow-up of 3.14 years, the primary outcome results are as follow:
    • Intensive treatment group – 102 events
    • Standard treatment group – 148 events
    • Hazard ratio 0.66 [95% CI, 0.51-0.85]
  • All cause mortality was a secondary outcome:
    • Intensive treatment group – 73 deaths
    • Standard treatment group – 107 deaths
    • Hazard ratio 0.67 [95% CI, 0.49-0.91]
  • Overall rate of serious adverse events: 
    • Intensive (48.4%), Standard (48.2%), HR 0.99 [95% CI, 0.89-1.11]
  • Absolute rates of hypotension
    • Intensive (2.4%), Standard (1.4%), HR 1.71 [95% CI , 0.97-3.09]
  •  Syncope
    • Intensive (3.0%), Standard (2.4%), HR 1.23 [95% CI , 0.76-2.00]
  • Electrolyte abnormalities
    • Intensive (4.0%), Standard (2.7%), HR 1.51 [95% CI, 0.99-2.33]
  • Acute Kidney Injury
    • Intensive (5.5%), Standard (4.0%), HR 1.41 [95% CI, 0.98-2.04]
  • Injurious falls
    • Intensive (4.9%), Standard (5.5%), HR 0.91 [95% CI, 0.65-1.29]

 Here are my thoughts:

  • Lowering the systolic blood pressure target to 120mmHg seems to offer additional cardiovascular benefits. However these results cannot be extrapolated to individuals with diabetes, prevalent stroke or heart failure because they were excluded in the study.
  • The study was also limited to elderly in the community dwelling and results cannot be extrapolated to people living in a nursing home setting.
  • It is evident that the intensive treatment group experienced more adverse events such as hypotension, syncope, acute kidney injury and electrolyte abnormalities. But contrary to common beliefs, the intensive treatment group did not have higher rate of injurious falls.
  • The study attempted to look at how frailty may be linked to outcome.
    • Among both treatment groups, more frail individuals were observed to have higher event rates.
    • However when individuals belonging to the same frailty scale were compared, the intensive treatment group was observed to have lower event rate.
    • More frail individuals were noted to experience more serious adverse events but the details were not reported.
    • It is important to note that these analyses were exploratory in nature and it may be premature to draw any conclusion based solely on these results.
  • In my opinion, these results suggest that perhaps lowering the systolic blood pressure target to 120mmHg may offer additional cardiovascular benefits in the elderly population who are “relatively healthy”  (e.g. without diabetes, prevalent stroke or heart failure).
  • But for the frail elderly living in a nursing home, it may be best to still keep the blood pressure higher for now.

 

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