Wednesday, September 29, 2010

Cancer Risk from CT Scan Exposure May Be Higher than You Think

According to two recent studies the cancer risk from radiation exposure may be higher than once thought. Berrington de Gonzalez and colleagues published two papers in the December 14/28, 2009 issue of Archives of Internal Medicine. One study postulates that CT scans in the U.S. in the year 2007 will lead to some 29,000 new cancers in the future. The largest number of cancers will result from CT scans of the abdomen.

The second paper investigated the variation in CT scan technique at four hospitals in the San Francisco area. The authors found wide variations in radiation dose due to different settings on the devices and the radiation exposure was much higher than previously published data suggested. For example, the median exposure from an abdominal CT scan was 31 millisieverts, a figure about four times higher than the usually quoted range.

For comparison, a CT scan of the abdomen and pelvis with contrast has an estimated radiation exposure to the patient of some 234 routine chest x-rays. A CT coronary angiogram exposes a patient to the same dose of radiation as 309 chest x-rays.

Editorialists in both Archives of Internal Medicine and JAMA expressed great concern and call for tighter regulation. The radiologists are also considering measures to try to decrease the number of CT scans done in the U.S.

Sunday, September 26, 2010

Delayed Appendectomy: A Different Kind of Peer Review


It seems that USA Today writer Rita Rubin is pushing an agenda which is that appendectomy for acute appendicitis should be delayed until it is convenient for the surgeon. The first article she wrote on this was in September of 2010. A similar article was published today. I blogged about this issue when the original article appeared. Here is my critique of the paper the articles were based on and why the concept of delaying appendectomy is not practical. I had entitled the post “A Different Kind of Peer Review” because the idea was reviewed by prospective patients in the form of comments on the USA Today website back in September.

The seemingly straightforward paper entitled “Effect of delay to operation on outcomes in adults with acute appendicitis” was published in a respected journal by a large and geographically diverse group of surgeons. The authors looked at almost 33,000 patients with appendicitis who underwent appendectomy at different time intervals after being admitted to a hospital. The data were collected from the American College of Surgeons National Surgical Quality Improvement Program [NSQIP] database over the four years from 2005 through 2008. They found no significant differences in risk-adjusted 30-day complication or mortality rates whether the patients underwent appendectomy within 6 hours of surgical service admission, 6 to 12 hours after admission or more than 12 hours after admission.

The authors acknowledged several limitations of the study. It was retrospective and therefore reasons for the delays to surgery for most patients could not be determined. The data were taken from a database with limited clinical information. Absent were data on antibiotic usage, fluids administered and reasons for choosing the laparoscopic or open approach to appendectomy. The authors and the accompanying editorialist suggested that since the outcomes were comparable it would be acceptable to delay appendectomy until daylight hours and have a well-rested surgeon perform the appendectomy. Allusions were made to possible money savings by not having operating room staffs and anesthesiologists awakened and called in at night, but no data were presented to support this theory.

Not mentioned by the authors but occurring to me are some other issues. The NSQIP database is contributed to on a voluntary basis by mostly academic tertiary care medical centers. I doubt the findings of this study are universally applicable. The three groups of patients based on the timing of the surgery were not really similar. In fact they were statistically significantly different and arguably clinically different in almost all respects. I don’t know about the authors’ practice patterns, but at every hospital I have ever worked in, including my present one, waiting to do an appendectomy until the morning means that someone’s elective surgery will have to be “bumped” [delayed] while I do my appendectomy. This causes the elective schedule to run late and staff has to work overtime [$$$$$] anyway. Also, most private practice surgeons need to get these cases done so they don’t interfere with office hours or their own elective surgery cases. Most patients with uncomplicated acute appendicitis can undergo laparoscopic appendectomy and be discharged home well within 24 hours of arriving at the hospital. Delaying the surgery for several hours will lead to increased lengths of stay and more costs and charges.

Then there is the little problem of the patients and their desires. Here is where the “Different Kind of Peer Review” comes in. Of the more than 40 comments about the September 2010 article posted online, the overwhelming majority expressed extreme negativity regarding waiting to have an appendectomy. Commenters railed against pain and suffering while waiting for surgery, government rationing of healthcare and lazy, avaricious doctors. Anecdotes about perforation of the appendix, peritonitis, near-death and veganism [yes, veganism] were offered. Similar sentiments are being expressed by the commenters on today's article. Finally, a surgeon would have a difficult time defending a lawsuit by someone who waited 12 hours for an appendectomy only to have a bad outcome due to perforation, sepsis, abscess and/or reoperation. That would emphatically negate any money saved by waiting, assuming such saving even exists.

I do not see delayed appendectomy catching on soon. What do you think?

Wednesday, September 22, 2010

How Does Science Daily Pick Its Subject Matter?

Ever wonder how Science Daily chooses which research articles to feature on their website? I have. As a total skeptic regarding the applicability of Six Sigma to medicine [see my previous blogs about Six Sigma], a recent post on Science Daily caught my eye. This was a glowing report entitled “Reducing waiting time at an emergency department using design for Six Sigma and discrete event simulation.” It’s about an emergency department in Jordan whose patient waiting times and lengths of stay [LOS] purportedly have been significantly reduced thanks to the miracle that is Six Sigma. The paper appeared in a journal called the International Journal of Six Sigma and Competitive Advantage.

I obtained a copy of the complete paper and have the following observations:

1. The authors already knew the waiting times and LOS were long.
2. They developed a mathematical model based on patient surveys to prove what they already knew.
3. The waiting time data were based on “…a random sample of 96 patients…measured over two random months and shifts.” The LOS data were from “…a random sample of 67 patients…measured over two random months and shifts.” The method of randomization was not stated. The number of patients studied represents 0.075% of all patients seen per year in their ED.
4. There are complex tables and flow charts.
5. Verification that the process was improved was based solely on simulation, not actual performance.
6 The impact factor of the International Journal of Six Sigma and Competitive Advantage is just about zero.
7. Don’t look for this article in PubMed.

So, you might ask, why was this paper featured on Science Daily? This is important because a posting on Science Daily is read by far more people than those who read most journals. Most of the information posted on Science Daily is from press releases generated by the authors of papers or their institutions. When describing how to contribute material, Science Daily states "Please note that we cannot guarantee posting of all the releases we receive, since we try to select those which we think would be of most interest to our readers." Someone from Science Daily is choosing what to post and we don't know how or why.

An email, the only way to contact Science Daily, sent on 8/31/10 asking about this has yet to be answered.

Tuesday, September 14, 2010

Study Reports Hand Washing Among the Public Is Increasing But the Data May Be Flawed

A new study seems to show that hand washing is on the rise nationwide and that a very high percentage of people in this country wash their hands in multiple situations. The study has two phases: a telephone survey and an observational tally of hand washing behavior in public restrooms.

If one believes the data, 96% of telephone respondents claim they always wash their hands after using a public restroom, 89% stated that they always wash after using the bathroom at home and 77% say they always wash before eating. For those observed in restrooms, 77% of over 6000 subjects washed their hands. Women were more diligent than men. The rate of hand washing has increased since the last iteration of the study in 2007.

So what are the possible problems with this study?

The telephone survey involved a carefully planned selection of all levels of society. Obviously, one had to have and answer a telephone to be included.

For the telephone survey, the results are of course self-reported. That is, the interviewer had to take the word of the respondent. Would it not be human nature to want to please the questioner and/or avoid embarrassment and answer the question “Do you always wash your hands after using a public restroom?” with a “Yes”? Proof that this is true is illustrated by the observational data, which shows a 19% lower rate of hand washing in public restrooms compared to the 96% response in the telephone survey.

For the observational component of the study, the subjects are clearly not a well-distributed cross-section of society. One must look at the venues. For reasons known only to the authors of the study, they chose [with two notable exceptions] some fairly upscale locations to observe hand washing. One venue was Atlanta’s Turner Field, home of baseball’s Braves. Ticket prices are mostly $25.00 and up and food and other prices are undoubtedly high as well. Other venues were the Chicago Museum of Science and Industry and the Chicago Aquarium. Both places are likely to attract higher socioeconomic groups. In San Francisco, they chose the Ferry Terminal Farmers Market. If one looks at the merchants in that market, one notes an artisanal cheese shop, a chocolate maker, two olive oil stores, a gelato stand and a number of other rather high-end emporia. The more proletarian [but possibly not] sites were New York City’s Grand Central and Penn Stations. On the one hand [pun intended], there are thousands of presumably employed suburbanites commuting into and out of the city daily. This group is tempered somewhat by a small but highly visible cadre of folks who live in and under these stations and [when and if they wash] wash not only their hands but a lot of other body parts in the restrooms.

Bottom line: The telephone survey results are dubious at best. Hand washing may be increasing among upper middle class and upper class urban and suburban people who frequent museums, stadiums and trendy California malls but one cannot assume that these data are applicable to the entire country.

Sunday, September 12, 2010

Moderate Alcohol Intake Is Good for You

According to a recent article in the journal Alcoholism: Clinical and Experimental Research, people with moderate alcohol intake had the lowest mortality rate of all groups compared to light drinkers, heavy drinkers and abstainers. The study involved 1824 Californians between the ages of 55 and 65 at baseline. Light drinking was defined as drinking an average of up to one drink per day. Moderate was defined as drinking an average of one to less than three [or two, if you are math challenged] drinks per day. Heavy was defined as drinking three or more drinks per day. Abstainers were people who had previously used alcohol but had become abstainers sometime before the start of the study. This was a very well-designed observational study with an end point of all-cause mortality after 20 years.

When age and gender were controlled [statistical techniques were used to remove variations among groups] the results showed that compared to moderate drinkers, abstainers had more than twice the risk of dying, heavy drinkers had 70% more risk and light drinkers had 23% more risk. This risk was cumulative over the 20 years that the subjects were followed. Even when all other covariates were controlled, moderate drinking was associated with the lowest mortality rate and abstention with the highest mortality rate.

The authors caution that there are limitations to this study including the following: it was observational and not a true experiment; the drinking data were self-reported [that is, the subjects themselves stated how much they drank]; lifelong abstainers were excluded [the study included only abstainers who had stopped drinking alcohol]; all drinking groups may have experienced episodic heavier drinking, which was not accounted for.

In a Science Daily report, the lead author stressed the word “moderation” and also pointed out that the study should not be interpreted as endorsing the concept that lifelong abstainers should start drinking to live longer.

With science on our side, let’s have cocktails! [See related post on How to Make a Great Vodka Martini.]

How to Make a Great Vodka Martini

UPDATED June 6, 2011

1. Any vodka will do. Trust me, Smirnoff's is as good as Ketel One or Grey Goose. Here is the “proof” [pun intended].
2. No flavored vodka. EVER!
3. Do not use vodka from the freezer. It's important for the vodka to melt the ice a little.
4. Add at least 3-5 drops of dry vermouth. It's got to have vermouth. Otherwise it's straight vodka, which is fine with me, but then it's not a Martini.
5a. James Bond was right. Shaken, not stirred. Let it sit for 30 seconds or so to allow the ice to melt a little. This takes the edge off the vodka.
5b. Shake as hard as you can so that some of the ice flakes off and is poured into the glass.
6. A Martini must be served "straight up" in a real Martini glass, which must be chilled. No plastic glasses please. If someone tries to give you a plastic glass, order something else.
7. One or more large green olives; no pits please; stuffing is optional. Pimento is the standard stuffing. I prefer garlic- or jalapeƱo-stuffed olives.
8. Extra juice from the olive jar (so-called "dirty Martini") is acceptable for some but not for me.

I'll have one when I'm off duty. Cheers!


The following are all names of actual journals that seem really interesting. If I only had more time...

Anadolu Kardiyoloji Dergisi-The Anatolian Journal of Cardiology
Antioxidants & Redox Signaling
Archives of Budo [Look it up; I did.]
Cell Adhesion and Communication
Cell Communication and Adhesion [Yes, they are two different journals.]
Cell Stress & Chaperones [Who knew they needed chaperones?]
Cladistics [See Archives of Budo.]
Climacteric [Not exactly what you think.]
Compost Science & Utilization
Current Opinion in Colloid & Interface Science
Hip International [Groovy. Dig it, baby.]
Hippocampus [A place of higher learning for these large animals.]
Hyperfine Interactions
International Journal of Ad Hoc and Ubiquitous Computing
International Journal of Alternative Propulsion
International Journal of Metaheuristics [I never met a heuristic I didn't like.]
International Journal of Nuclear Desalination
International Journal of Six Sigma and Competitive Advantage
International Journal of Water
Journal of Buon
Journal of Happiness Studies [!]
Journal of Nanophotonics
Journal of Nonverbal Behavior [No comment.]
Journal of Paleolimnology
Journal of Supercritical Fluids [Bad enough when they're just critical, but supercritical?]
Journal of the Philosophy of Sport
Journal of the Renin-Angiotensin-Aldosterone System
Journal of Turbulence
Lab on a Chip [A new hors d'oeuvre?]
Menopause-The Journal of the North American Menopause Society [I once went to one of this society's meetings. All day long half the audience said the room was too cold; the other half said the room was too hot.]
Nebraska Symposium on Motivation [Can't think of a better venue for that symposium.]
Phosphorus Sulfur and Silicon and the Related Elements
Proceedings of the Steklov Institute of Mathematics
Sex Roles
Superlattices And Microstructures
Tetrahedron Letters [Soon to be renamed Tetrahedron Emails or perhaps merged with the next journal on the list.]
Text & Talk
Travail Humain

Wednesday, September 8, 2010

Bad Medical Advice from Men’s Health Magazine and Yahoo

Here is some incredibly stupid advice from Men’s Health magazine in August which was given more exposure today by Yahoo Health. It’s from an article about allegedly common misdiagnoses. The advice is in italics.

Diagnosis: Appendicitis
What you might really have: An inflamed lymph node or stomach virus

Despite advances in diagnostic screening, 16 percent of appendectomies are performed on patients who don't need them, according to a recent University of Washington study. Appendicitis can be deadly, so doctors are quick to remove the 6-centimeter organ before doing a CT scan to confirm the diagnosis. An inflamed lymph node or virus could produce similar symptoms (and not require surgery).

Your strategy: If blood tests reveal that your white-cell count is over 10,000 cells per microliter, ask for a CT scan of your stomach.

A previous blog post of mine discusses the diagnosis of appendicitis in detail.

Let me dissect (pun intended) this erroneous advice line by line.

Despite advances in diagnostic screening, 16 percent of appendectomies are performed on patients who don't need them, according to a recent University of Washington study. This is outdated information based on an article from an administrative database. As my previous blog post points out, it does not reflect the current accepted misdiagnosis rate for appendicitis, which is well below 10%.

Appendicitis can be deadly, so doctors are quick to remove the 6-centimeter organ before doing a CT scan to confirm the diagnosis. This is patently untrue. According to a study from Cornell and consistent with my experience and that of many others, over 90% of patients undergoing appendectomy in the 21st century undergo a CT scan before their surgery.

An inflamed lymph node or virus could produce similar symptoms (and not require surgery). This rather simplistic statement is sort of true but incomplete. Many other illness can be confused with appendicitis.

Your strategy: If blood tests reveal that your white-cell count is over 10,000 cells per microliter, ask for a CT scan of your stomach. The white blood cell count is a very soft indicator of appendicitis. It can be normal in more than 10% of cases and an elevated white blood cell count is non-specific. The white blood cell count can be elevated in many diseases that are not appendicitis.

There is also the question of unnecessary radiation exposure and a possible increased risk of later developing cancer which suggests that the last thing one should do is tell people to request a CT scan because of some arbitrary white blood cell count threshold. This is a prime example of why you should not get your health advice from the internet.

Sunday, September 5, 2010

Junk Food and Hospitals

A recent study found that children who eat vended junk snack foods tend to maintain poor dietary habits which may lead to obesity, diabetes and arteriosclerosis. According to the LA Times, “The researchers – from the University of Michigan, Michigan State University and Food & Nutrition Database Research Inc. of Okemos, Mich. – calculated that all that snacking adds up to about 14 extra pounds per child per school year.”

Every hospital I have ever worked in or even visited had numerous snack and soda vending machines and served what I would generously call “less than nutritious” food in its cafeteria. How often have you seen a morbidly obese visitor or even a patient walking away from a vending area with a bag of potato chips and a soda?

Why is it that hospitals, even inner city public hospitals which serve only the indigent, promote poor nutrition? I think I may have a clue.

A paper from several months ago reported that if junk foods are removed from schools, children eat less junk food. Why would schools want to provide their students with junk foods? In an interview with Science Daily, the lead author of that study “…explained that financial pressure from both the food industry, looking to build brand loyalty, and the schools, which get a cut of the profits from vending machines, is the main reason there is opposition to removing soft drinks and junk foods.”

Could this be the case with hospitals as well? I have no doubt. So we have the hypocrisy of hospitals sponsoring screening programs for all kinds of diseases and promoting their lucrative bariatric surgery services, while they are fattening up the clientele with junk foods and drinks. Can I be the only observer who has noticed this?