by Dr. John Beasley, M.D.
Nothing like preventive maintenance for both you and your airplane, right? Overhaul at TBO. Well, as the song goes, “It ain’t necessarily so,” whether we are talking about airplanes or people. For airplanes, a convincing argument can be made that we have more engines failing because of routine overhauls done at TBO than would be failing if we ignored the TBO. If you haven’t seen it, try the Webinar by EAA’s Mike Busch at http://www.eaavideo.org/video.aspx?v=1429764450001. You can get the same slant on things in his March, 2011 Sport Aviation article at http://www.sportaviationonline.org/sportaviation/201103?pg=100.
The aphorism for today is “There is no free lunch.” Whether we are working on airplanes or people, stuff happens, and it is not always what we intended. Engines fail more often after overhauls than at any other time, but how about people?
A while back, I was listening to a nationally syndicated medical talk show, and an airline pilot called in and said “I just found out my PSA (a test for prostate cancer) is elevated…what should I do?” I know the talk show host and emailed him, “For heaven’s sake, tell him to stop testing!” Why would I say that? Prostate cancer isn’t a great disease and 3% of us who have a Y chromosome will probably die from it. But at the same time, there is strong evidence that intervening doesn’t make much difference. We probably have to do surgery or something to somewhere between 8 and 48 patients to avert one death, and some studies show no benefit at all. And if the PSA is high, then there are some rather unpleasant tests to check it out, and again, best case chances are 7 out of 8 that the treatment will either not be needed (you will die of something else such as old age) or not be successful (and you go ahead and die of the cancer despite treatment). The treatment is fraught with side effects, and, as for the caller, there are certification issues.
What are the upsides of screening? In some cases (screening for colon cancer for people over 50 – and under 80 – or earlier for some), there is good evidence that for most people the benefits exceed the risks. For mammography, there is reasonably good evidence too.
What are the downsides? Cost and discomfort are two, but there are also unnecessary, ineffective or even harmful diagnostic procedures and treatments that result from screening.
How can you tell if screening is really a good idea for your age and gender? The best information about the utility of various health-screening measures comes from the U.S. Public Health Services Preventive Services Task Force. They are at: http://www.ahrq.gov/clinic/uspstfix.htm Specifics for age and gender are at: http://epss.ahrq.gov/ePSS/search.jsp
The ratings come in several categories:
Level A: Good scientific evidence suggests that the benefits of the clinical service substantially outweigh the potential risks. Clinicians should discuss the service with eligible patients.
Level B: At least fair scientific evidence suggests that the benefits outweigh the potential risks. Clinicians should discuss the service with eligible patients.
Level C: At least fair scientific evidence suggests that there are benefits, but the balance between benefits and risks are too close to call. Clinicians need not offer it unless there are individual considerations.
Level D: At least fair scientific evidence suggests that the risks outweigh potential benefits. Clinicians should not routinely offer the service to asymptomatic patients.
Level I: Scientific evidence is lacking, of poor quality, or conflicting and the risk versus benefit balance cannot be assessed. Clinicians should help patients understand the uncertainty surrounding the clinical service.
Once you know the level of rating, it is time to have a chat with your doc. And, the value of screening depends not only at the potential harms and benefits, but what you (the patient) want. A rational person could say, “I’m really worried about cancer and want you to do all the screening you can. An equally rational person might say, “I feel great and I don’t want you messing with me unless you can show me that it’s really likely to help me! How you feel about these issues should help us decide what’s useful to you – not just useful to statisticians.
So what to do? Chat with your doc, and do the obvious to stay healthy. I won’t belabor the obvious.
