Tuesday, February 27, 2007

Using the MeSH Browser as a dictionary

Sandra of Discovering Biology in a Digital World provides a great discussion of the MeSH Browser, "MeSH part I. Where can you find the meaning of "life"?"

Noting that you can't often get a "quick" definition for a scientific term straight from a scientist, she also points out that the authority and precision of definitions provided by Google or Wikipedia may not be reliable enough for understanding the basics of a particular scientific word or phrase.

Sandra then gives a nice overview of how to find definitions using the scope notes available via NCBI's MeSH database.

It's so easy to focus on MeSH as a means to an end, a way to find the "right" terms to find good articles in PubMed on a topic, but Sandra's post reminded me that the MeSH database can serve as a reference resource all on its own.

In addition to using the scope notes to understand a term's meaning, a few other "uses" that come to mind:
- using the tree structures to begin to understand which body systems are affected by a given disease and how different conditions are related to each other
- looking at the entry terms to figure out common synonyms for a subject heading
- using the spell check/suggestion feature to "decode" a medical word (drug, disease, etc) that I've heard but never seen in print, or that's I just find difficult to spell correctly

For those interested in more on the history and functions of MeSH, including another version of the MeSH browser, check out the NLM's MeSH page.


Friday, February 23, 2007

C. diff makes headlines in the UK

The impact of Clostridium difficile infection on mortality is increasingly in the public eye. With the headline "Hospital bug deaths on the rise," the BBC News site picks up recent data announced by the UK's Office for National Statistics about a continuing increase in both mentions of Clostridium difficile on death certificates in England and Wales, accompanied by an increase in the number of times C. diff is noted as underlying cause of death.

The statistics brief (credit: the bar graph to the left) was posted yesterday.

The ONC notes that increased public and clinician awareness of C. diff has likely contributed to the increase in reporting (i.e. difficult to differentiate how much the incidence of infection is increasing versus the contribution of diagnosing it more accurately).

Wednesday, February 21, 2007

Utility of Case Reports Covered in Current MLA News

Rebecca Jerome, JMLA co-editor, has authored a piece for the Expert Searching column in this month's MLA News, "When Is the Case Report Useful in Answering Clinical Questions?" The article discusses the benefits and limitations of using case reports to inform clinical care, the important role of case reports in building drug safety and adverse events knowledge, and a new journal dedicated to presenting novel information via case reports.

This informative article is well worth a read. Feel free to leave questions or thoughts on the role of case reports in the comment sections for this post.

MLA News is available online to Medical Library Association members.

Friday, February 16, 2007

When is observational data "enough"?

An article by Glasziou et al. in today's British Journal of Medicine, "When are randomised trials necessary? Picking signal from noise," considers when observational data is sufficient in establishing the effectiveness of a treatment.

It gives a number of examples to illustrate situations in which RCTs are probably unnecessary, when the signal to noise ratio is unlikely to be explained by other biases (i.e. inferences about a direct relationship between the treatment and improvement in the condition are large, in the right sequence, and not likely to be due to other influences) - the examples range from laser treatment of portwine stains to tracheostomy for tracheal obstruction to blood transfusion for severe hemorrhage-related shock.

For a more tongue-in-cheek look at this issue, try this article: Smith GC, Pell JP. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. BMJ. 2003 Dec 20;327(7429):1459-61. PubMed abstract
CONCLUSIONS: As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.

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Tuesday, February 13, 2007

MLA video on health sciences librarianship

If you are visiting the blog and interested in what it means to be a librarian that works in medicine and the life sciences, check out this great 11 minute video produced by the Medical Library Association - "Join the Health Care Team: Become a Medical Librarian."

It features brief interviews with several different librarians that provide great snippets of their everyday life and contributions - their excitement for what they do and the way they support healthcare comes across very clearly, inspiring to watch (bonus - it also has a pretty cool soundtrack).

It's available in Windows Media Player and Quicktime formats for high and low bandwidths.

There are also brochures, tip sheets, a database of mentors, and other advice for prospective medical librarians available on MLANET.


Wednesday, February 07, 2007

Case reports and post-marketing surveillance

The Food and Drug Administration has launched an online training seminar, "FDA MedWatch and Patient Safety," about the role of the MedWatch program in monitoring drug, device, blood, and other biologic product safety in the US.

It's a fantastic and informative course, about an hour of video presentation, covering the role that the program plays in monitoring safety after drugs, devices, etc, are approved by the FDA - commonly called "post-marketing surveillance."

Programs like this realize that, while clinical trials are designed to establish general safety and efficacy of the products regulated by the FDA, they do not have adequate size to detect all possible side effects; the MedWatch program is particularly interested in serious adverse events associated with these products, i.e. those causing significant morbidity and mortality to individuals taking the drug. This type of program also is intended to catch issues with:
- how drugs are prescribed (what patients and physicians "do" with the drugs outside of the controlled setting of a clinical trial, such as problems with how they're dosed, possible interactions with other medications, etc)
- how devices or other products are used in the "real world"
- quality of products (issues regarding how the devices, drugs, products are produced and distributed to patients, e.g. faulty devices, manufacturing/handling errors leading to problems with the end product, etc)

The stated objectives of the MedWatch program:

- To educate both healthcare providers and their patients about the importance
of reporting serious adverse events IN to FDA, and to facilitate that reporting

- then…once those reports have been received and evaluated by FDA, to
take the new safety information that results from analysis of these reports and
disseminate it OUT from FDA and back to clinicians and their patients, in a
timely fashion for use at the point of care.

The FDA pulls these reports together, analyzes and investigates them, and determines an appropriate course of action for dealing with an issue that truly exists. Any interventions or changes are often accompanied by educational strategies aimed at the provider and the patient.

The MedWatch site notes:

Changes to the label, also known as the prescribing information or package insert, are the most commonly used strategy. These range from boxed warnings placed at the top of the prescribing information, to additional statements in contraindications, precautions or adverse reactions sections about new interactions, monitoring recommendations or dosage adjustments. Certain drugs are required to have medication guides - a 'patient-friendly' instruction sheet that is provided to the patient by the pharmacist each time a prescription is dispensed.
How does this tie in to this month's case study?

The foundation of the MedWatch program is voluntary and mandatory reporting of adverse events (errors, product problems, side effects) potentially associated with FDA-regulated products -- in essence, providers and patients sharing case reports of problems potentially associated with the products. Investigators at the FDA use principles of epidemiology to wade through all of the case reports, identify clusters or common issues, investigate those issues, and figure out which problems are "real" and begin figuring out what to do with them -- all based on case reports from providers and patients.

The system is not without its flaws, and potential reform at the FDA is currently the subject of much attention and debate in the US consumer and healthcare communities. An editorial in JAMA highlights some of the main critiques or weaknesses of the current system, and proposes potential solutions for addressing these issues:

Editorial: Fontanarosa PB, Rennie D, DeAngelis CD. Postmarketing surveillance--lack of vigilance, lack of trust. JAMA. 2004 Dec 1;292(21):2647-50. (PubMed abstract with link to free full-text)

Additional information:
- A transcript of the presentation is available here.
- There are a number of articles looking at how MedWatch data is used, available via a quick PubMed search.
- Additional discussion of the FDA's post-marketing surveillance strategies is available on their Center for Drug Evaluation and Research (CDER) site.