Research on Dangers of Sleep Apnea

Knock knock, anybody home. Sleep apnea is highly correlated with age and excess weight. These are in turn highly correlated with dying. Therefore, it seems very likely that a major portion of the correlation between sleep apnea and dying is spurious and a result of age and excess weight. In other words, a major portion of the causal connection (theory) which you imply, probably does not exist.

I would appreciate a response to the above comment because I am thinking about adding this research to a causal statistics book that I am writing, as yet another example of the incompetent research, implying inappropriate causal inferences. It may be that, as sometimes happens, the research and the conclusions are okay, but that the incompetence is in the summarization. I would appreciate your input on these possibilities.

C. Sterling Portwood, Ph.D.

Dicatated via Dragon NaturallySpeaking, but not read.

I was also left wondering about the conclusions. The article says persons whose sleep apnea was untreated were 4 times as likely to die from any cause vs. 3 times as likely for those treated with CPAP. I guess that's sort of good news for CPAP, but you're still 3 times as likely to die from apnea even if you're treated?

Either CPAP is significantly less effective than its promoters suggest, or as DR. Portwood suggests, there may be something else killing these CPAP-treated patients.

It's understandable that Dr. Portwood would reach his conclusions after reading the above report of the article in Sleep. The report is poor. Reading the article which the above report purports to summarize shows that the study accounted for age, body mass index, and sex as well. Dr. Portwood's skepticism not withstanding, people in the tested group with untreated sleep apnea had an hazard ratio for death from all causes that was 3 timed higher that the general population with the same mix of age, body mass index, and sex.

The study in this article was performed in the US. Another article in the same issue of Sleep reported on a similar study performed in Australia over a period of 14 years. The results were similar.

Ignoring the greatly increased risk of premature death that accompanies untreated sleep apnea is perilous, even if the reports of it are poorly done. Both the general public and the medical profession need to take heed.

Burton Abrams

To respond to Doug McKenzie's question requires careful reading of the Sleep paper. There were 1522 randomly selected participants ages 30 to 60 at the outset of the study, of which 220 were in the mild sleep apnea/hypopnea category at the study's outset, 82 were in the moderate category, and 63 were in the severe category. At the study outset 126 participants reported using CPAP at least 4 nights per week, so most of those with sleep apnea (249) did not use CPAP with that frequency. There was no attempt made to ascertain whether CPAP usage changed over the 18 year period of the study, or whether the pressurization was correctly adjusted. Thus, the authors warn of the limitations of their CPAP usage data. The paper does not designate how many of the CPAP users were in each category. Even with the limitations of the CPAP data, when those 126 admitted CPAP users were deleted from the data base, the risk of mortality in the severe category went from 3.0 to 3.8 for the 18 year period studied. These results indicate some benefit in life expectancy by using CPAP, but the benefit can't be quantified from these data. One cannot correctly conclude that without CPAP usage a person with sleep apnea is 4 times as likely to die vs. 3 times as likely to die when using CPAP.

I read an artical on oral appliance therapy and would like to see if some one could give me some feed back. This report said this treatment is for mild to moderate apnea. Has there been any research to compare cpap to oral therapy and if so where was that done and how do I view it. It is my understanding that 23-45% with cpap is efective only because of partical compliance by the person using this device and this is for severe cases. During my stay in the hospital mine appears to be moderate. I am having a sleep apena study done in late September to confirm this and I would like to have as much information as possible so I can discuss this with my specialist. It seems there are so many studies and as many opinions for each. There is not a sure way for me to know but I could be informed enough to make a somewhat logical choice. I can filter out what I consider to be shakey reports and opinions and decide with the help of my Doctor,"If needed". Again I think cpap would have need to be tested for compliance by the user to get real results. Anyone have an answer?