Reporting of prognostic markers: current problems and development of guidelines for evidence-based practice in the future

Prognostic markers help to stratify patients for treatment by identifying patients with different risks of outcome (e.g. recurrence of disease), and are important tools in the management of cancer and many other diseases. Systematic review and meta-analytical approaches to identifying the most valuable prognostic markers are needed because (sometimes conflicting) evidence relating to markers is often published across a number of studies. To investigate the practicality of this approach, an empirical investigation of a systematic review of tumour markers for neuroblastoma was performed; 260 studies of prognostic markers were identified, which considered 130 different markers

Cardiovascular Risk with Non-Steroidal Anti-Inflammatory Drugs: Systematic Review of Population-Based Controlled Observational Studies

David Henry and colleagues reevaluate the evidence from observational studies on the cardiovascular risk associated with non-steroidal anti-inflammatory drugs

Incongruence between test statistics and <it>P </it>values in medical papers

<p>Abstract</p> <p>Background</p> <p>Given an observed test statistic and its degrees of freedom, one may compute the observed <it>P </it>value with most statistical packages. It is unknown to what extent test statistics and <it>P </it>values are congruent in published medical papers.</p> <p>Methods</p> <p>We checked the congruence of statistical results reported in all the papers of volumes 409–412 of <it>Nature </it>(2001) and a random sample of 63 results from volumes 322–323 of <it>BMJ </it>(2001). We also tested whether the frequencies of the last digit of a sample of 610 test statistics deviated from a uniform distribution (i.e., equally probable digits).</p> <p>Results</p> <p>11.6% (21 of 181) and 11.1% (7 of 63) of the statistical results published in <it>Nature </it>and <it>BMJ </it>respectively during 2001 were incongruent, probably mostly due to rounding, transcription, or type-setting errors. At least one such error appeared in 38% and 25% of the papers of <it>Nature </it>and <it>BMJ</it>, respectively. In 12% of the cases, the significance level might change one or more orders of magnitude. The frequencies of the last digit of statistics deviated from the uniform distribution and suggested digit preference in rounding and reporting.</p> <p>Conclusions</p> <p>This incongruence of test statistics and <it>P </it>values is another example that statistical practice is generally poor, even in the most renowned scientific journals, and that quality of papers should be more controlled and valued.</p