Home / Tag Archives: Medical Studies (page 7)

Tag Archives: Medical Studies

A New "Silent Killer"?

Hypertension has often been dubbed the “silent killer” because most people don’t feel any different when their blood pressure is elevated, yet longstanding hypertension has adverse effects on so many organ systems – heart, brain, eyes, kidneys, etc – that it will eventually kill the patient if the hypertension is left untreated. A study out this month in the journal “Gastroenterology” shows that there may be a new “silent killer” on the block. The authors analyzed blood samples from 9100 adults at the Warren Air Force Base collected between 1948 and 1954, looking for serum markers of celiac disease. They then compared the rates of undiagnosed celiac disease with recent blood samples from patients in a Minnesota town. The study had two surprising conclusions. First, the incidence of celiac disease in patients 60 years ago was 0.2% while the incidence of celiac disease in the current blood samples was 0.8% to 0.9%. I wasn’t able to access the whole study on the Gastroenterology web site, but other confounding factors such as sampling bias may have explained at least some of these differences. Second, patients with undiagnosed celiac disease had a nearly 4-fold increase in risk of death during the 45 year follow up period. Again, correlation does not necessarily mean causation, so it would be interesting to see the causes of death in the study population. Untreated celiac disease is associated with an increased incidence of lymphomas, thyroid disease, and gastrointestinal cancers, so an increase in death from those diseases in the study population would be more impressive than a bunch of deaths from car accidents or drug overdoses. Celiac disease was featured in an episode of “House” and has affected Elisabeth Hasselbeck from “The View”. Will have to go to the medical library and pull the article to read through it further, but just found the conclusions surprising.

Read More »

"Stone Heart" = Stone Ages?

Here’s a post for the medical brainiacs out there. It used to be a “pimp” question during medical rounds: Why don’t you give calcium to someone taking digoxin? Answer: It could either cause an arrhythmia or could cause tetany of the heart, also known as “stone heart.” A clinical pearl just out from eMedHome.com shows that there have been only 5 reported cases of fatal dysrhythmias with concomitant digoxin and calcium use. The pearl also notes that theoretical and extremely rare risks of administering calcium in patients with digoxin poisoning must be weighed against the increased mortality in patients with digoxin toxicity who remain hyperkalemic. Since calcium exerts an antiarrhythmic effect in hyperkalemia, it is often recommended in the stabilization of someone suffering from high potassium levels. The question then becomes: Which is worse, giving the calcium or risking an arrhythmia? One of the studies cited in the eMedHome article by Levine et al. showed that among patients with digoxin toxicity, calcium administration non-significantly increased mortality (22% versus 20%). On the other hand, each 1 mEq/L rise in serum potassium concentration made it 1.5 times more likely that a patient would die. Note that the study only included 161 patients and that only 23 of those patients received calcium, so the “n” isn’t huge. Still a judgment call, but it appears as if calcium in hyperkalemic patients with digoxin toxicity may help more than it hurts. References used in the eMedHome article are below (1) Levine M, et al. The Effects of Intravenous Calcium in Patients with Digoxin Toxicity J Emerg Med 2009 Feb 5. (2)Fenton F, et al. Hyperkalemia and digoxin toxicity in a patient with kidney failure Ann Emerg Med 1996;28:440-441. (3)Van Deusen SK, et al. Treatment of hyperkalemia in a patient with unrecognized digitalis toxicity J Toxicol Clin Toxicol 2003;41:373-376.

Read More »

What Do Hypertension and Ulcers Have In Common?

Answer: They were both thought to be due to “stress” at one point, but were later linked to infectious processes. Most ulcers are now known to be caused by Helicobacter pylori, or H. pylori for short. Now a new study in the Public Library of Science shows that hypertension may be caused by cytomegalovirus infections. CMV apparently increases inflammation in the blood vessel walls and increases the secretion of both renin and angiotensin II – both known to contribute to hypertension. CMV infection plus a high cholesterol diet also caused atherosclerosis in the aorta while CMV infection without high cholesterol did not. Any pharmaceutical company that has a hypertension medication on patent is not going to be happy about this study. Then again, Roche stock is probably going to make a nice little jump as Roche makes ganciclovir and valganciclovir – both medications used to treat CMV. Roche also makes a little-known drug called Tamiflu. Wouldn’t it be wild if all the hypertensive medications were rendered useless by an antiviral drug? I’d be interested to see whether HIV patients on chronic treatment for CMV retinitis are any less likely to have hypertension. Additional news stories from: Reuters, Medpage Today, and the Associated Press

Read More »

Antibiotics More Harm Than Good For Strep Throat?

One of EP Monthly’s newest contributors, Dr. David Newman (of the “Hippocrates’ Shadow” fame), sets out a compelling case for why antibiotics may do more harm than good when treating strep throats. The results of the studies showing that antibiotics prevent rheumatic fever may surprise you. This article is another example of the medical profession needing to examine treatments we consider as “standard of care” to determine whether the treatments are effective and whether the risk of the treatments outweighs the benefit of their use. Also an interesting discussion in the comments section of the article on whether antibiotics prevent glomerulonephritis or retropharyngeal abscesses. Chris Carpenter, who is an EBM guru, responds to those questions as well. ER Stories also has some discussion on the topic. Embarassed to say that TK scooped me on an article on my own site. UPDATE MARCH 22, 2009 Medscape recently published a short article containing updated guidelines for management of streptococcal pharyngitis. Important points to note include the following: Strep throat is self-limiting and resolves within a few days. [emphasis mine] The rationale for antibiotic treatment is prevention of suppurative infection, prevention of rheumatic fever, and reduction of communicability The antibiotic of choice is penicillin because no increase in resistance has been seen for the past 50 years Despite appropriate antibiotic treatment, chronic strep colonization is common. Children can be chronic “strep” carriers (i.e. strep present on culture without any signs of infection) for up to 1 year after infection, but there is generally no need to treat chronic carriers because they are thought to be at low risk of transmitting disease or developing invasive GABHS infections. [again, emphasis mine] In summary, strep throat will go away on its own without antibiotic treatment and we only treat to reduce side effects that don’t occur that much to begin with. In addition, if we swab family members of people who have strep “just to make sure” they don’t have it too, when we give antibiotics to those with positive results, we’re probably treating patients who have been colonized and won’t benefit from antibiotics anyway. Finally, a question. The article notes that there has been no increase in the resistance of Group A strep to penicillin in 50 years. There is not a consensus on this issue. If we assume that strep has not become resistant to penicillin, could it be that the strep infections we are “treating” with penicillin would just have gone away anyway and that the penicillin is just a “placebo”? Looks like a great opportunity for a randomized study. Another recent Medscape article highlights the strep treatment/rheumatic fever reduction issue.

Read More »

Decreasing Your Chance of Stroke

According to a February 19 article in the BMJ Online in which 20,000 patients were followed for 11 years, four factors significantly affected the study participants’ risk of having a stroke. Smoking, physical inactivity, drinking no alcohol or more than 14 drinks per week, and not eating fruit and vegetables increased study participants’ risk of stroke from 1.15 times to 2.31 times – depending on how many of the four activities participants did and did not engage in. The study was a little weak in that it was based on a survey where the questions could have led to misleading data. For example, to determine smoking, the survey questions asked “Have you ever smoked as much as one cigarette a day for as long as a year?” and “Do you smoke cigarettes now?” Those patients who engaged in smoking/quitting cycles might not have been picked up by the survey, and those who smoked lightly for a couple of years as a teenager but quit decades ago would still have been counted as “smokers.” In addition, the study used serum Vitamin C levels as a surrogate marker of fruit/vegetable intake. While not the best data, the results still give you something to think about. Stop smoking, have a beer after work, get off your butt and eat your veggies. Hat tip to Medscape CME.

Read More »

The Windows Vista Effect

For those of you who actually use Windows Vista, what do you do when the User Account Control pops up a message like the one above? Maybe the first few times you read it and see what the program is all about. After that, you glance at it when it pops up and click “Continue”. After a month or so, it grows to be a real pain in the but-tocks and you tend to ignore, or even get frustrated with it. A recent Archives of Internal Medicine study titled “Overrides of Medication Alerts in Ambulatory Care” shows that the same concept holds true when doctors prescribe medications through a computer program. Researchers studied more than 3.5 million electronic prescriptions written using a specific electronic prescribing system in several states between January and September 2006. They tracked 2872 total clinicians, looking to see how the clinicians would respond to “alerts” programmed into the electronic prescribing system. Alerts were programmed for allergies to medications and for potentially dangerous interactions between drugs being prescribed. Of the 3.5 million prescriptions tracked, roughly half a million total “alerts” were generated by the electronic prescribing system. Half of those alerts were excluded by the researchers because they were “duplicate” alerts that occurred after the prescriber overrode the first alert. The remaining 233,000 alerts were then studied to show how often prescribers accepted the alerts. Not surprisingly, the alerts were often ignored. “Drug-Drug Interaction” alerts were overridden 91% of the time and “allergy” alerts were overridden 77% of the time. The researchers concluded that “Given the high override rate of all alerts, it appears that the utility of electronic medication alerts in outpatient practice is grossly inadequate … For active clinicians, most alerts may be more of a nuisance than an asset.” I had three other thoughts about the study. First, it proves that the more you computerize patient records, the more that the data will be tracked and analyzed. I really believe that data mining is the major impetus for the electronic medical record initiative pushed by the government. Second, it shows how forcing clinicians to jump through more and more micromanagement and regulatory hoops in order to practice medicine won’t necessarily have the intended effect. It would be interesting to compare the productivity of the clinicians before and after the electronic medical record system was instituted. Finally, the study shows that at least some of the “warnings” about drug interactions and drug allergies are theoretical ones and not clinical ones. There were a quarter million prescriptions written in this study that were against the better judgment of some computer program. Even though the prescriptions were written in 2006, I still haven’t heard about all the gloom and doom adverse patient outcomes tied to those those hundreds of thousands of transgressions. Could it be that there were very few adverse outcomes and that the “warnings” were mostly overblown? Like to see those study results.

Read More »