April 26, 2008
TORCH Analysis
American Family Physician (paid subscribers only) has a great analysis of the TORCH study. TORCH (Toward a Revolution in COPD Health) was a large, randomized, double-blind trial studying a treatment for COPD (emphysema). The particular treatment they were studying has great theory behind it, but came under question a few years ago for increasing deaths in kids treated for asthma with the combination.
What Mark Graber points out in this Journal Club format is that not only is the mortality not affected by these drugs alone or in combination, but the benefits touted for the drug are not very meaningful. The NNT (Number Needed to Treat) to prevent an exacerbation of COPD is 4, which is good. But the NNT for one year to prevent a hospitalization is 33. That means that 33 patients have to be treated with this medicine to even keep one out of the hospital. That is of arguable meaningfulness.
Where the study is deceptive is in downplaying the increase in cases of pneumonia. The NNH (number need to harm) for one year for pneumonia is 41. If 41 people are treated for one year, there will be one additional case of pneumonia in the combination treatment group. These did not translate to deaths, apparently. But certainly the benefit is offset by the harm.
The Journal Club also points out that there were a lot of dropouts from the study, and all the drugs were made by the drug company sponsoring the study, with no comparison with other helpful treatments in COPD.
It is refreshing to see an increase in such analyses.
Posted by Robert Maddox at 09:24 PM | Comments (0)
April 07, 2008
Trading measles for seizures
After yet another long lapse, I post. As I am my primary audience, this does not bother me. I know how much reading and studying I do, how many patients are cared for in the intervening days and weeks. If you object, let me know.
An article in Family Practice News summarizes data from the KP Vaccine Study Center's Dr. Klein, whose analysis of the Vaccine Safety Datalink data for that week in February showed an increase in post vaccination seizures for MMRV (the combination of MMR with Varicella -chickenpox). There were 5 additional seizures for every 10,000 children who received the MMRV instead of the separate vaccines.
So how many seizures were there after the separate vaccines? Well, depends on how many days post vaccination and which vaccines you are asking about. The biggest cluster is at 7 -10 days post vaccination, with 9.6 for MMRV, 4.9 for MMR plus a separate V, 3.5 for MMR alone, and 1.5 for varicella alone. But the "expected number of seizures total after MMRV is 14.7/10,000 or 1/680. The increase that caught their attention was to 1/440 or 22.7/10,000.
The discussion is on whether administering these vaccines together is worth this possible extra risk.
But based on my previous discussions of vaccine efficacy, my question is whether they are worth it at all. Remember that these diseases are very rarely fatal. The vaccines are sold on the promise of peace of mind. But if one in 500 will have a seizure, up to 42 days after administration, how peaceful will the parents' minds be?
Posted by Robert Maddox at 04:46 PM | Comments (0)
February 21, 2008
Adverse Drug Reactions
Interesting article here by a Pharm D on ADRs, makes this statement:
"Contrary to the public's common belief, all drugs are dangerous. Just because a drug is approved by the US Food and Drug Administration (FDA) does not mean that it won't cause problems; all usually do, from minor side effects to permanent disability, to life threats, and even death.[1-3] The FDA approves drugs on the basis of benefits outweighing the risks, not because there is a complete lack of danger."
Good overview of the ways that patients, pharmacists and physicians generally view adverse drug reactions.
Posted by Robert Maddox at 10:48 AM | Comments (0)
January 24, 2008
CT scan cancer
The NEJM published a study last month (or Nov. 29, 2007) which estimated that CT scans are responsible for 1.5% - 2% of all cancers. There are 62 million scans done in America each year. This was merely a calculation based on cancer effects on the 25,000 Japanese who survived the atomic explosions. They do reasonably estimate that the lifetime attributable cancer risk of necessary CTs is very small and must be weighed against the benefit.
But it should give those pause who advocate CT for cancer and CAD screening.
Posted by Robert Maddox at 01:18 PM | Comments (0)
June 28, 2007
Ear infections
Ear infections are always a great concern of parents, who don't want to see their children suffer, and would do almost anything to help them. An old review, updated recently by Prof. Del Mar for BMJ, gives a picture not commonly understood by even most doctors.
Middle ear infections ( known as AOM-Acute Otitis Media) always get better, with or without treatment. There are few complications from AOM anymore (for whatever reasons), and antibiotics do not prevent them anyhow.
80% of children feel better by the next day, whether they are treated or not.
Starting an antibiotic early in the course would reduce the chance of pain by a third. IOW, from 20% to 14% (there's that relative risk reduction again). This means that 100 children would have to be treated to benefit 6, for a NNT (number needed to treat) of 17 for 1 to benefit by less pain days 2-7.
And if that were the whole story, we might all conclude that the cost and trouble of taking an unnecessary antibiotic would be worth it.
But what about the harm of antibiotics? The diarrhea, the abdominal pain, the rash? 30% So 5 of our 17 will be harmed in some way by the unnecessary antibiotic. To help one with pain, we harm five. That is iatrogenesis. Medicine is harming more than it helps.
Posted by Robert Maddox at 05:40 PM | Comments (0)
June 26, 2007
echinacea
Lancet has published a meta analysis of echinacea to prevent and treat the common cold. There are 1 billion colds a year in the US. I will not pay for this article online and do not have access to the article so I am relying on the news articles (of which there must have been thousands). They found (not clear if this was over the whole meta-analysis or in one of the 14 studies reviewed) a 58% reduction in colds and shortened the course by a day and a half. Are they implying that there could be less than half a billion colds next year if we all took echinacea?
Did they study the percentage who had bad allergic reactions? The absolute worst case of anaphylaxis I have ever seen in 20 years of ER was from echinacea. And an Australian study showed up to 20% of atopics had severe allergic reactions of one type or another. Do we really want 4% of the population to have life-threatening reactions just to prevent the common cold?
I personally hate a cold. And I occasionally take Vit C and Zinc based on Art Robinson's research back in Linus Pauling's lab, thinking I am warding off a cold a few times a year. But I am not sure that even that pill-popping is worth the trouble.
Posted by Robert Maddox at 01:14 PM | Comments (2)
May 09, 2007
Pneumococcal vaccine
I haven't dealt with vaccines in general yet, nor many of the specifics. But this tidbit from JAMA April 25 is too good to pass up.
"The vaccines against Hib and pneumococcus seem like a good idea. Those germs are the cause of much childhood disease. Hib (a bacteria) was the most common cause of meningitis, as well as a major cause of epiglotitis, cellulitis, pneumonia, and a host of other infections. Some of these carried a high mortality rate. It seems to make good sense to vaccinate against such a killer. Maybe the death rate has been reduced from 1/5000, or 10,000 to maybe 1/100,000. (I am guessing at those figures.) But it seems to me that other organisms have just risen to take its place." I wrote a few weeks ago.
Now this from JAMA on pneumococcus. The vaccine was 7-valent (it had 7 types mixed together). The incidence of invasive pneumococcal disease caused by these types decreased, as hoped. But other types have increased and are causing almost as high an incidence as pre-vaccine. What else would we expect? Do we really think we can conquer all disease? Won't the death rate still be one a piece?
Posted by Robert Maddox at 12:53 AM | Comments (0)
May 03, 2007
MICU misdiagnosis
One does not have to search far for examples of clinical iatrogenesis. But one must also be careful of accepting every report of misdiagnosis and error. A study published in Chest in 2001 looked at records of 1800 admissions to a MICU. Of the 401 patients that died, 91 had autopsies. Eighteen of those had a different diagnosis from that which was made clinically. Eight of those were considered major, with a direct impact on therapy. The other ten patients had an unexpected major finding, but would not have changed therapy. So is the conclusion that one in five ICU deaths are misdiagnosed? (18/91)
Continue reading "MICU misdiagnosis"
Posted by Robert Maddox at 10:23 PM | Comments (0)