Monday, March 14, 2005

Celiac Disease,Osteoporosis and Screening

Stenson et al writing in the Feb. 28, 2005 Archives of Internal Medicine report the results from screening women for celiac disease (CD) in the Washington University bone health tertiary referral center. Finding a prevalence of 3.4 %, they recommend screening osteoporosis patients with two sensitive and specific blood tests (anti-TTG and anti-EMA). The women in the underwent diagnostic endoscopy to confirm the diagnosis.The companion editorial suggests that if both tests are positive perhaps the endoscopy could be avoided.Cost considerations then become mandatory when screening for anything is at issue.
Dr.Bauchman in his editorial proceeds though the usual protocol of estimating the number of patients with a given condition who would need to be screened, the cost of screening all of them and the cost in this instance to prevent a fracture.We are told it would cost 2 billion dollars to screen the osteoporotic population.
The cost of the two blood tests are about $200.The 2 billion figure is what the Medical Czar of a country would consider. But then we have no medical czar and the relevant number is really the cost of screening for a given patient.The real life questions becomes will " insurance pay for it" and if not would the patient be willing to pay the money herself and will the physician be sued for missing a diagnosis if he does not test. Publications seem to always discuss these matters in global terms when maybe the locus of interest should be the individual doctor-patient interaction and relevant factors in that transaction.

Tuesday, March 01, 2005

Two insightful articles on Guidelines and why they should not be a major indication of "quality"

An excellent article by Tinetti et al in the December 30, 2004 NEJM explains problems with guidelines particularly as disease specific guides are applied to patients with multiple illnesses. The second article is in The New Yorker by Atul Gawande and deals specifically with cystic fibrosis centers which apparently are a guideline dominated enterprise and how the very best such places go beyond guidelines. Guidelines are great for folks who purport to measure quality because they are easy to use. It recalls the old story that talks about the drunk who searched for his lost keys under the street light- not because he lost them there but because it was the easiest place to look. Some of the pitfalls Tinnetti writes about are:1) the guidelines are often based on RCTs(often with relatively small improvements in relative risks) that have cherry picked subjects who do not have other illnesses,and exclude older people and go for a relatively short times whereas in real life patients have many problems , get old and take pills for a long time.2) patients with several illnesses might just not have the same priorities as the trialists and may opt to not take all of the meds that Multiple guidelines offer,3) multiple drugs have multiple interactions.Extrapolating from RCTs that exclude many of the patients actually seen by doctors to recommendations about those patients seems to involve more faith based that evidence based medicine.Worse yet, physicians who have philosophical problems with those extrapolations may be judged to not be practicing quality medicine. The issue here is should RCTs' conclusions be construed narrowly- ie to those only like the participants in the study- or broadly -ie to include patients whose characteristics would have not allowed them to be eligible for the trial. Perhaps older more experienced physicians are more able to see when guidelines are appropriate and when they are not: when patient preferences and other variables trump the guideline's suggestions.
Quality assurance programs have as a given that variations are not desirable but there are appropriate variations due to the various specificities of the patients and the patient's own preferences. QA programs assume variations are bad. Gawande's article make the point that something more than adherence to guidelines makes a program great. It seems that it has something to do with having a great doctor involved: one who understands the basis for the guidelines and knows when to innovate and improvise. So much of medical care is improvisation by the physician and the patient. There is a sense in which QA program miss that point entirely.

Saturday, February 26, 2005

TB Rx= quadruple therapy plus liver and onions

Actually, you can hold the onions. The February 2005 issue of Chest published an article taking a very old observation(low cholesterol in tb patients) and decided to do something about it.What they did was a clinical trial involving giving cholesterol rich diet to see if a metric of improvement would occur quicker.Actually a couple of indicators did.By week 2, 8/10 in the treatment group achieved a negative culture while only 1/11 in the control group was negative.The authors also reported that sputum production decreased faster in the treatment group.Since 90% plus of tb patients are sputum negative by 6 mos anyway it is not likely that high fat diet diets for a couple of weeks will add much to the final outcome(and this is the era of outcome research)

Wednesday, February 23, 2005

WHI Strikes Again, A RCT trumps a systematic review and we learn estrogen does not help urinary incontinence

Once again we see a RCT provide a conclusion opposite to that supplied by a systematic review even one done by the legendary Cochrane Group. A 2003 Cochrane review (Moehrer B ,Jextall A, Jackson S, Oestrogens for urinary incontinence in women. Cochrane Data Base Sys rev.2003:(2) CD001405) concluded that oral estrogen treatment could improve or cure incontinence but ,of course, in appropriately cautious tones, recommended further study.
The further study is found in the February 23, 2005 issue of JAMA. Data from the Women's Health Initiative (WHI) showed that estrogen alone and estrogen plus MPA increased the risk of urinary incontinence in continent women and worsened the incontinence in symptomatic women after one year. In a related editorial Dr. Catherine DuBeau attempts to unravel the knotty aspects of biological plausibility and the ins and outs of methodological issues involved in part to try and understand why oral estrogen would worsen incontinence and why progestin seemed to mitigate the effect of estrogen on urge incontinence in the WHI data. The relative risks, though statistically significant,were generally less than 2 and maybe the play of chance is at work in some of the subgroup data. But the bottom line is doctors will likely not be prescribing oral estrogen for urinary incontinence after reading the WHI paper. We await further investigation on the use of topical estrogen.

Tuesday, February 22, 2005

Prophylactic antibiotics in Surgical Patients

A large survey published in the February 2005 Archives of Surgery reported that 99% of Medicare patients undergoing any of the five surgical procedures they reviewed received prophylactic antibiotics.1% developed wound infections. 92 % received antibiotics in compliance with published guidelines. Areas that the authors suggested could be problem areas were : possibly as many as 60 % received antibiotics for periods longer that some would say is optimal, possible overuse of vancomycin, and not all received the antibiotics within the usually recommended one hour of incision (Although, the exact time of incisions was frequently not recorded so this data is a bit soft) . The authors admited that their vancomycin-use analysis was limited by the fact they had no information about the frequency of MRSA in the various hospitals. These criticisms notwithstanding the apparent bottom line is there seems to be a very low incidence of sugical site infections. Duration of antibiotic therapy continues to be an area with more opinion that data. Critics of health care won't find much about which to express alarm but they will find something.

Saturday, February 19, 2005

The Perfect Country and Western Song-The perfect Medical article

In the David Allan Coe song, "You never even called me by my name" we are told some of the essential components of the " perfect" country song. Things that should be mentioned are: trains, trucks, mama,prison and getting drunk.
There are also essential components of the perfect medical article and should appear in the introduction and/or the discussion and summary sections. They include: mention of evidence based medicine (this is required even if the article has little if any evidence actually presented), mention of the disease at issue being "a public health problem"(saying it is common is not enough), a word about "quality" and perhaps most importantly stating that "we must be good stewards in this era of scarity of medical resources ". Unlike the essential elements of C&W music, which are timeless, the medical article sine qua nons are of recent vintage.
Non C&W fans may claim that tired cliches populate some country songs. It could be claimed that "floating abstractions" and politically correct comments are the fluffy fillers of the perfect medical articles.

Friday, February 18, 2005

Likelihood ratios and Evidence Based Medicine, what does the evidence show?

Part of the teachings of EMB is the use of the likelihood ratio. It is defined as the likelihood that a given test result would be expected in a patient with the disease of interest compared to the likelihood that the same result would be expected in someone without that disease. To use one , you have to "estimate" the pretest probability of a disease in a given setting. It has always appeared to me that this means- much of the time- you simply make up a number.If that is true, a group of doctors given the same clinical scenario would make up different numbers. Now there is evidence that this is exactly what happens. Drs. Phelps and Levitt (Acad. Emerg. Med,2004 June:11 (6) 691-694) gave clinical vignettes to a group of IM and ER trainees and attendings and asked them to estimate the likelihood of several illnesses. The numbers varied widely.The smallest difference in the pretest probability was 70%. If you think about "making up" a number as opposed to "estimating" a number, the validity of the whole process is perceived differently. Here, at least, the "evidence" that a particular element of Evidence Based Medicine is valid in a simulated real world setting is lacking and in fact suggests that it is not. The Ontario EMB experts in their book "Evidence Based Medicine" indicate there are several ways to estimate the pretest probability besides the physician using her experience including national and regional data bases. But in the real world it seems that the most common way of estimating pretest probability is to use one's own experience because such data is either non existent or you cannot access it. In this regard perhaps older, more experienced doctors would have the edge.
EMB dogma states that the likelihood ratio is the best way to judge how much a test result help to make the diagnosis. In theory this is clearly the case but the scheme does not work very well if the pretest probability value is is so nebulous.