Pubmed vs. Full-Text Query Performance in Systematic Reviews : Application to Non-inferiority Clinical Trials

André Nguyen Van Nhieu1, 2, Katet Moez1, Michel Nougairede 2, Xavier Duval4, Michaël Schwarzinger1 1 ATIP-AVENIR Inserm “Modélisation, Aide à la Décision, et Coût-Efficacité en Maladie Infectieuses”, U738, Université Denis Diderot, Paris, France; 2 Département de Médecine Générale, Université Denis Diderot, Paris, France3 Inserm U738, Université Denis Diderot, Paris, France; 4 Inserm CIC 007, AP-HP, Hôpital Universitaire Bichat, Paris, France

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I declare no conflicts of interest

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Introduction (1)

Systematic review = extensive research of appropriate publications in the literature

Usually performed through Pubmed using key-words

Methodology appropriate when keywords in title/abstract and MeSH

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Introduction (2)

Comparison of Pubmed VS FULL-TEXT

Application: Non-inferiority trials in infectious diseases1

According to Piaggio CONSORT statement JAMA 2006: improving quality of reporting Non-inferiority trials

Hypothesis : Pubmed as sensitive as FULL-TEXT

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Objective

To compare the performance of 2 query strategies to identify non-inferiority trials with mortality as a primary outcome in infectious diseases: Pubmed Full-text using the search engine of each

journal

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Methods (1)

Original articles published in 2001-2012 In :

Generalist journals : N Engl J Med, Lancet, JAMA, Ann Intern Med, BMJ, Arch Intern Med

Specialist journals : Lancet Infectious Disease, Clinical Infectious Disease, Journal of Infectious Disease, AIDS, Vaccine, Pediatrics, PlosMed

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Methods (2)

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Using : PUBMED : keywords : [randomi* AND (non?

inferior* OR not inferior OR is inferior OR was inferior) AND (surviv* OR alive OR mortality OR death* OR fatal*)] + indexation (randomized controlled trial, Kaplan-Meier method, survival, mortality, death)

FULL-TEXT method with the same keywords adapted according to each search engine

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Methods (3)

Methods (4)

Definitions : True positive (TP): Non-inferiority trial (NIT) with

mortality as primary outcome found by one or the other query strategy

False positive (FP): Original article but it is not a NIT or a NIT with primary outcome ≠ mortality

False negative (FN): NIT fount by one query search but not the other

Positive predictive value (PPV): probability to find a TP among all Positive of a query strategy

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Results (1)

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Flowchart

Articles excluded (n=101):- 88 articles with survival as a secondary outcome- 13 articles with per protocol analysis  

256 articles in infectious diseases identified in PUBMED

and FULL-TEXT : 81 in common and 175 more with

FULL-TEXT

Articles excluded (n= 28):- 28 NIT with outcome different from mortality

Articles excluded(N=72) : - 8 Reviews- 3 Observational studies - 17 Pooled analysis- 11 SUP RCT phase 2 - 23 SUP RCT phase 3  - 4 equivalence trials - 2 secondary analysis- 4 follow-up of NIT     

184 Non-inferiority trials

156 Non-inferiority with mortality in the outcome

55 Non-inferiority with mortality as a primary outcome = TP

  

False positiveTrue positive

Results (2)

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FULL-TEXT

PUBMED Sensitivity Positive Predictive Value

55/55 (100%)

19/55 (34,5%)

55/256 (21,5%)

19/45 (42,2%)

False negative 0/55 (0%)

36/55 (65,5%)

Results (3)

Subgroup analysis : Sensitivity not different between

generalist / specialist journals (p=0,14) Sensitivity FULL-TEXT & Pubmed not

different <2008 / >2008 (p=0,07)

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Limits of FULL-TEXT method

1) Repetition in each journal search engine2) Specificity of each journal search engine :

learning curve3) Access to journals for GP is not free 4) Time consuming

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Conclusion (1)

FULL-TEXT is 100% sensitive Pubmed detects only 34,5% of non-

inferiority trials in infectious diseases High rate of false positive in FULL-TEXT However, False Positive easily identified

and excluded through reading

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Conclusion (2)

Testing the Full-text method in other medical fields or repeating in a few years (improving Pubmed?)

Improvement to be made with CONSORT statement

Adding Non-inferiority in MeSh terms

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THANK YOU

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Bibliography

Le Henanff et al. / RAVAUD Quality of Reporting of Noninferiority and Equivalence Randomized Trial JAMA 2010

Piaggio et al. Reporting of Noninferiority and Equivalence Randomized Trials JAMA 2006 and Extension of the CONSORT 2010 Statement JAMA 2012