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Pitfalls of retrospective database studies

30 Mar

As you know a part of my work consists to participate in studies based on the extraction from retrospective databases and the analysis of the informations thus retrieved. The eligibility of the beneficiaries to the provision that represents the study’s outcome is always a major concern. There is two explanations for a beneficiary not having access to a care according to the data retrieved from the reimbursement base: either a real lack of access or a non eligibility of the care for a record in the reimbursement data base (for example if the insured is covered by another insurance or has lost his coverage and has exited from the health plan)*. I have always to keep in mind that I work on secondary data which are only a reflection of the primary data the reality of which I try to apprehend.
The dilemma is pretty well addressed in this article:

http://onlinelibrary.wiley.com/doi/10.1046/j.1524-4733.2003.00242.x/full

*as always there is a third possibility: the data concerning the care has been erased from or not yet recorded in the base. The timeline of the refreshment of the base (ie the loading and the purifying of the data) must be precisely described in the methodology of the study.

Article cited:
1)- Motheral, B., Brooks, J., Clark, M. A., Crown, W. H., Davey, P., Hutchins, D., Martin, B. C. and Stang, P. (2003),

A Checklist for Retrospective Database Studies—Report of the ISPOR Task Force on Retrospective Databases.

Value in Health, 6: 90–97. doi: 10.1046/j.1524-4733.2003.00242.x

Two other articles address the pitfalls of inferring from secondary data extracted from a retrospective data base:

2)- Berger M, Mamdani M, Atkins D, Johnson M.

Good Research Practices for Comparative Effectiveness Research: Defining, Reporting and Interpreting Nonrandomized Studies of Treatment Effects Using Secondary Data Sources: The ISPOR Good Research Practices for Retrospective Database Analysis Task Force Report—Part I.

Value in Health 2009 ; 12(8) :1044-52
3)-

The use of claims databases for outcomes research : Rationale, challenges, and strategies. Annual international meeting of the Association for Pharmacoeconomics and Outcome Research.

Philadelphia, Pennsylvania (USA), 1996/05/12. CLINICAL THERAPEUTICS, vol. 19, n° 2, 1997, pages 346-366, 74 réf., ISSN 0149-2918, USA. MOTHERAL (B.R.) *, FAIRMAN (K.A.). Outcomes Research. Express Scripts. Inc. Maryland Heights. USA

Full text of the article here:

http://ehealthecon.hsinetwork.com/Motheral_ClinTher_1997.pdf

 

The Decrease of life expectancy.

18 Mar

For the first time in history life expectancy decreases in a industrialized country as shown in the study below:

content.healthaffairs.org/content/31/8/1803.abstract

The New York time reported one of the key result of the study in a article entitled “Life Spans Shrink for Least-Educated Whites in the U.S.”here:

http://www.nytimes.com/2012/09/21/us/life-expectancy-for-less-educated-whites-in-us-is-shrinking.html?pagewanted=all&_moc.semityn.www&_r=0

These data must be integrated to the social policies that are based on the assumption that the upcoming generations will live longer.

Paul Krugman, the Nobel prize of economy, explains this reversing trend by the increase of income inequalities at a macroeconomic level here:

http://www.healthypolicies.com/2012/09/paul-krugman-america’s-greatest-public-health-champion/

Breast cancer mortality and screening: results of a randomized trial approved by the School of Public Health, University of Toronto, Toronto, Ontario M5T 3M7, Canada;

15 Feb

In 1980 the School of Public Health, University of Toronto, Toronto, Ontario M5T 3M7, Canada approved a randomized controlled trial: 89 835 women, aged 40 to 59, were affected at random to either an annual mammogram during five years or an annual physical examination without any mammogram during the same period of time. Now 25 years after the results are publicly available here:

http://press.psprings.co.uk/bmj/february/breastscreening.pdf

And they are astonishing, so astonishing that we feel compelled to quote them:

“Conclusion Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when adjuvant therapy for breast cancer is freely available. Overall, 22% (106/484) of screen detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial.”

Meaning: not only searchers did not find any evidence of difference in the instantaneous risk of death from breast cancer between the two groups (hazard ratio not significantly different from one) but moreover what they found was over-diagnosis of breast cancers (ie 106 more cancers in the mammogram group even 15 years after the screening that is even when all the cancers of the non screening group should have been detected due to their natural evolution).

Those chilling facts have to be discussed, that is the least that we should do in the health services community given the budget allocated to breast cancer screening by mammograms.

Perhaps the mammographies in the eighties were not as sophisticated as those which are offered now? And in the contrary physicians in the eighties were perhaps more efficient than the 21century doctors at the physical examination of the breast?

Thanks to the incidental economist who gave me the news:

http://theincidentaleconomist.com/wordpress/horribly-depressing-news-about-mammograms/

Hospital Spending Intensity and Patient Outcomes

25 Dec
English: Data Source http://www.irdes.fr/EcoSa...

English: Data Source http://www.irdes.fr/EcoSante/DownLoad/OECDHealthData_FrequentlyRequestedData.xls (OECD Health Data 2009). Health care cost rise based on total expenditure on health as % of GDP. Countries are USA, Germany, Austria, Switzerland, United Kingdom and Canada. (Photo credit: Wikipedia)

An amazing study implemented by Canadian health services researchers and published in the Journal of American Medical Association, suggests that depending which side of the border between Canada and the USA you live on, the consumption of the same expensive acute health cares results in different outcomes in term of patient’s health and quality of care. In other words, it is not so a matter of “how much” but rather a matter of “how” when it comes to question the legitimacy of a nation’s health care expenditures. The authors schedule to extend the field of their study to European countries and also to the long-term cares of chronic conditions.

http://m.youtube.com/#/watch?sns=fb&v=EOm2Ommqq5c&desktop_uri=%2Fwatch%3Fv%3DEOm2Ommqq5c%26sns%3Dfb&gl=FR

How to assess the validity of an analysis and a data collection

18 Nov
Psychological Science (journal)

Psychological Science (journal) (Photo credit: Wikipedia)

This article about the methodological concerns in psychological science should inspire the health services authors. It is amazing how easily one can obtain false positive results in a survey when the researchers use all the degrees of freedom that they dispose.
The article:
http://people.psych.cornell.edu/~jec7/pcd%20pubs/simmonsetal11.pdf

Can our body’s language change our mind?

6 Oct

This social psychologist in Harvard business school gives a speech about the body’s language. Two French politicians are  used to illustrate the course. Guess who they are…

And yet it warms

12 Aug
Galileo Galilei / 1564 - 1642

Galileo Galilei / 1564 – 1642 (Photo credit: *The Boy From Cerrado)

And yet it moves.
(Galileo Galilei, June 22nd 1633)
Paraphrasing the famous quote attributed to Galileo in the 17th century, another physicist, Richard A Muller could confess ” and yet it warms”, thinking of the same object: our mother earth.
During the recent years scientists have harshly debated to know if the global warming was a reality or a myth (by the lifetime of Galileo it should have been called an heresy). Data mining and crunching the figures, the Professor of the University of California, Berkeley, a former tenant of the non warming camp, changed his mind when he analyzed the shapes of the various curbs he obtained from a chronological series of temperatures making a jump back in time of 250 years.
He disseminated those results in free access scientific journals and on line at BerkeleyEarth.org, one thing Galileo could not do In his Time, unfortunately for him and his crazy idea that the hearth was moving (as crazy as saying that it is warming).
You can also read the press release for the lay public written by Prof. Richard A Muller in the July 30th edition of the IHT in France.

Dogs enhance the immunity system in children

21 Jul

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I cannot resist to post those two links toward scientific articles with the aim of giving a little advertisement for the benefit of our four legs companions!

http://onlinelibrary.wiley.com/doi/10.1034/j.1399-3038.2002.02063.x/abstract

Reference: Hölscher B, Frye C, Wichmann HE, Heinrich J. Exposure to pets and allergies in children. Pediatric Allergy and Immunology. 2002;13(5):334-341. Available from: http://dx.doi.org/10.1034/j.1399-3038.2002.02063.x.

http://pediatrics.aappublications.org/content/early/2012/07/03/peds.2011-2825.full.pdf?sid=1770172f-e6d1-4f38-890e-6d9c4e91a362

Reference: Bergroth E, Remes S, Pekkanen J, Kauppila T, Büchele G, Keski-Nisula L. Respiratory Tract Illnesses During the First Year of Life: Effect of Dog and Cat Contacts. Pediatrics. 2012 Jul;Available from: http://dx.doi.org/10.1542/peds.2011-2825.

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20120722-092648.jpg

Historical cohorts: strengths and weaknesses

8 Jul

Historic cohort study, generally means to take a look back at events that already have taken place.

database

database (Photo credit: Sean MacEntee)

With the huge data bases containing Millions of lines of historic of several years of reimbursements of health care and health conditions now at the disposal of nation wide health care insurances like CNAMTS or RSI in France or Kaiser Permanente or Veteran Affairs in the USA , historical cohorts such as the one that is described in the article referenced below are very easy to implement provided that researchers have access to the data base and use the appropriate software to extract accurately the information to transform rough data in a relevant medical information. Personally I am a fan of SAS enterprise guide (no funding by SAS to disclose for this Blog).
But nothing being perfect in this world the weakness of such historical cohorts retrospectively rebuilt is that they can only put in evidence associations without absolutely no hint but the possible causation process involved in the association. Their force is of course the number of subjects analyzed (usually huge) and the provenance of the subjects (community and real life subjects as opposed as the carefully selected subjects of the controlled randomized trials).
But at the end of the day, to conclude like the study referenced below does, that high doses of ACE treatment causes a lowering of the mortality rate and the readmission rate is obviously going beyond the proper results of the study. Indeed no observational historic cohort, whatever the size of the analysed sample is, has the power to demonstrate a causality link. One possible explanation of the association unveiled by the study is that prescribers could be more reluctant to give high doses of ACE to the more fragile groups and comorbidity incurring groups of the studied population.

More content and referenced study:

ARCH INTERN MED PUBLISHED ONLINE JULY 2, 2012 WWW.ARCHINTERNMED.COM

Improved Outcomes in Heart Failure Treated With High-Dose ACE Inhibitors and ARBs: A Population-Based Study: full text research letter

Female Sexual Dysfunction (FSD): a medical condition or a pharmaceutical firms invention ?

8 Jul

The race to create orgasm enhancing drugs to women has just begun.

Orgasm Inc - pix 08

Orgasm Inc – pix 08 (Photo credit: k-ideas)

Orgasm Inc - pix 10

Orgasm Inc – pix 10 (Photo credit: k-ideas)

An interesting article in Plos written by a Leonore Tiefer, a Professor of psychiatry, shed the light on how could be interacting the disease mongering in one hand and the sexual functions issues of women in a another hand. But the pitfall of such a position of suspecting systematically the pharmaceutical industry of being greedy could be to let those dysfunctions in the same uncomfortable situation as orphan diseases which as we know suffer from a lack of response (be they pharmaceutical responses or psychological responses, or technological response).

An article of press in the International Herald Tribune by Abby Ellin, in the July 4 edition takes a more balanced point a few when it reports in response to Dr Tiefer the words of Dr Marcus saying: “to say that women complains about their sex life because the pharmaceutical companies told them to is really insulting to women”

More content and references:

Plos site
Full text version of Pr Tiefer essay

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