June 2, 2015

Sleep Apnea May Cause Blood Pressure Increase

I am finding some consistency in articles about sleep apnea and how it affects other diseases or conditions the patient may have. A new meta-analysis conducted by an international team of sleep and respiratory researchers suggests that untreated sleep apnea may be a major factor in causing medications to be less effective in reducing hypertension (high blood pressure) in some people.

In reading the entire article, there are several things mentioned that makes this meta-analysis more valuable. These include:
  1. Using continuous positive airway pressure (CPAP) therapy may be a key to helping people with hard to treat hypertension.
  2. Most people with resistant hypertension also have obstructive sleep apnea (OSA).
  3. OSA and resistant hypertension is a deadly combination that exponentially increases the risk of death or disability from a stroke or heart attack.
  4. The study indicated that the patients with resistant hypertension and the very highest blood pressure experienced the greatest reduction in blood pressure after using CPAP therapy
  5. This response suggests that untreated sleep apnea may be why these people haven’t seen improvement in their blood pressure despite the concurrent use of three or four medications.

Ulysses Magalang, MD, the study’s principal investigator and director of the Sleep Disorders Center at The Ohio State University Wexner Medical Center and co-author Christopher Valentine, MD, a nephrologist at Ohio State’s Wexner Medical Center both say that these findings suggest that physicians may need to be more aggressive with screening for sleep apnea and ensuring CPAP therapy compliance in patients with resistant hypertension.

Dr. Valentine did say, “That there is evidence about the benefits of CPAP in people with hypertension and OSA, but ours is the first analysis to systematically review CPAP use in people with difficult to treat hypertension and apnea.” He continued, “The results are clinically relevant because the effects that we found are significantly higher than what’s been previously observed in a more general hypertensive population. CPAP use could offer this subset of patients a new chance to reach a healthier blood pressure goal, or even to reduce their medication burden.”

Drs. Magalang and Valentine say that their findings also support the idea that resistant hypertension and OSA represent an “extreme phenotype” of those who have OSA, but never develop hypertension. The researchers further suggest that resistant hypertension in those with sleep apnea may be caused by a less common gene variant that nonetheless has significant impact.

It’s a hypothesis that will likely be put to the test over the next decade. The researchers who collaborated on the paper all belong to the Sleep Apnea Genetics International Consortium (SAGIC), a partnership of scientists from five continents who are building the first-ever international biomedical database to uncover the genetic causes of sleep apnea. By collecting biological material from thousands of patients with sleep disorders, the group hopes to amass enough data to start identifying underlying genetic causes of different conditions.

We’re only just now beginning to appreciate the link between sleep apnea and disease,” said Magalang. “We hope that one day we will find common genes shared between people who have uncontrollable blood pressure and sleep apnea, and that will open up a whole new world of interventions and treatment strategies.”

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