Background:

Some people believe that likelihood ratios provide diagnostic information that is more useful than sensitivity and specificity estimates.

Objective:

To assess how physicians' estimates about probability of illness are affected by the presentation of a diagnostic test's value as an estimate of sensitivity and specificity versus a likelihood ratio or an inexact numerical graphic.

Design:

Random assignment of vignettes with different presentation formats of diagnostic test accuracy.

Setting:

Auditorium at a continuing medical education conference.

Participants:

183 physicians.

Intervention:

After estimating probabilities of 6 common illnesses described in patient vignettes, physicians reviewed pertinent test results presented in 1 of 3 formats.

Measurements:

Physicians' probability estimates of illness before and after receiving test information, and post-test probability estimates based on the Bayes theorem.

Results:

Absolute percentage point differences between the physicians' estimated and the Bayes-based post-test probabilities varied from −7 to 31, from −7 to 28, and from 1 to 29 for the sensitivity and specificity, likelihood ratio, and graphical groups, respectively. Mean differences of probability estimates between the sensitivity and specificity and the likelihood ratio groups were small for all vignettes (−2 to 3 percentage points; summary mean z value across the 6 vignettes, 0.04 [95% CI, −0.14 to 0.21]).

Limitations:

The small pool of participants (who were potentially selected) and the limited number of vignettes prevented a more detailed analysis of relationships between the interpreted strength of diagnostic evidence and estimations of illness probability.

Conclusions:

These findings suggest that presenting diagnostic test accuracy with likelihood ratios does not affect some physicians' estimates of illness probability compared with presenting diagnostic test results as sensitivity and specificity.

References

  • 1. Ledley RSLusted LBReasoning foundations of medical diagnosis; symbolic logic, probability, and value theory aid our understanding of how physicians reason. Science1959;130:9-21. [PMID: 13668531] CrossrefMedlineGoogle Scholar
  • 2. Reid MCLane DAFeinstein ARAcademic calculations versus clinical judgments: practicing physicians' use of quantitative measures of test accuracy. Am J Med1998;104:374-80. [PMID: 9576412] CrossrefMedlineGoogle Scholar
  • 3. Steurer JFischer JEBachmann LMKoller Mter Riet GCommunicating accuracy of tests to general practitioners: a controlled study. BMJ2002;324:824-6. [PMID: 11934776] CrossrefMedlineGoogle Scholar
  • 4. Hoffrage ULindsey SHertwig RGigerenzer GMedicine. Communicating statistical information. Science2000;290:2261-2. [PMID: 11188724] CrossrefMedlineGoogle Scholar
  • 5. Jaeschke RGuyatt GHSackett DLUsers' guides to the medical literature. III. How to use an article about a diagnostic test. B. What are the results and will they help me in caring for my patients? The Evidence-Based Medicine Working Group. JAMA1994;271:703-7. [PMID: 8309035] CrossrefMedlineGoogle Scholar
  • 6. Sox HCBlatt MAHiggins MCMarton KIMedical Decision Making. Newton, MA: Butterworth-Heinemann; 1988:67-102. Google Scholar
  • 7. Hunink MGlasziou PDecision Making in Health and Medicine: Integrating Evidence and Values. New York: Cambridge Univ Pr; 2001:128-76. Google Scholar
  • 8. Weinstein MCFineberg HVThe use of diagnostic information to revise probabilities. In: Clinical Decision Analysis. Philadelphia: WB Saunders; 1980:75-130. Google Scholar
  • 9. Ginsberg JSWells PSKearon CAnderson DCrowther MWeitz JIet alSensitivity and specificity of a rapid whole-blood assay for D-dimer in the diagnosis of pulmonary embolism. Ann Intern Med1998;129:1006-11. [PMID: 9867754] LinkGoogle Scholar
  • 10. Jaeschke RGuyatt GLijmer JGDiagnostic tests.. In: Guyatt G, Rennie D, eds. User's Guide to the Medical Literature. Chicago: American Med Assoc; 2002:121-40. Google Scholar
  • 11. Schouten HJCombined evidence from multiple outcomes in a clinical trial. J Clin Epidemiol2000;53:1137-44. [PMID: 11106887] CrossrefMedlineGoogle Scholar
  • 12. Bachmann LMSteurer Jter Riet GSimple presentation of test accuracy may lead to inflated disease probabilities [Letter]. BMJ2003;326:393. [PMID: 12586679] CrossrefMedlineGoogle Scholar
  • 13. Goehring CPerrier AMorabia ASpectrum bias: a quantitative and graphical analysis of the variability of medical diagnostic test performance. Stat Med2004;23:125-35. [PMID: 14695644] CrossrefMedlineGoogle Scholar
  • 14. Puhan MASteurer JBachmann LMter Riet GVariability in diagnostic probability estimates [Letter]. Ann Intern Med2004;141:578-9. [PMID: 15466782] LinkGoogle Scholar
  • 15. Bachmann LMter Riet GClark TJGupta JKKhan KSProbability analysis for diagnosis of endometrial hyperplasia and cancer in postmenopausal bleeding: an approach for a rational diagnostic workup. Acta Obstet Gynecol Scand2003;82:564-9. [PMID: 12780428] CrossrefMedlineGoogle Scholar
  • 16. Miettinen OSThe modern scientific physician: 3. Scientific diagnosis. CMAJ2001;165:781-2. [PMID: 11584568] MedlineGoogle Scholar
  • 17. Moons KGBiesheuvel CJGrobbee DETest research versus diagnostic research. Clin Chem2004;50:473-6. [PMID: 14981027] CrossrefMedlineGoogle Scholar
  • 18. Moons KGvan Es GADeckers JWHabbema JDGrobbee DELimitations of sensitivity, specificity, likelihood ratio, and bayes' theorem in assessing diagnostic probabilities: a clinical example. Epidemiology1997;8:12-7. [PMID: 9116087] CrossrefMedlineGoogle Scholar
  • 19. Irwig LBossuyt PGlasziou PGatsonis CLijmer JDesigning studies to ensure that estimates of test accuracy are transferable. BMJ2002;324:669-71. [PMID: 11895830] CrossrefMedlineGoogle Scholar
  • 20. Davie APFrancis CMLove MPCaruana LStarkey IRShaw TRet alValue of the electrocardiogram in identifying heart failure due to left ventricular systolic dysfunction. BMJ1996;312:222. [PMID: 8563589] CrossrefMedlineGoogle Scholar
  • 21. Innes GChristenson JWeaver WDLiu THoekstra JEvery Net alDiagnostic parameters of CK-MB and myoglobin related to chest pain duration. Canadian Journal of Emergency Medicine2002;4:. CrossrefGoogle Scholar
  • 22. Badgett RGTanaka DJHunt DKJelley MJFeinberg LESteiner JFet alCan moderate chronic obstructive pulmonary disease be diagnosed by historical and physical findings alone? Am J Med1993;94:188-96. [PMID: 8430714] CrossrefMedlineGoogle Scholar
  • 23. Salvarani CSilingardi MGhirarduzzi ALo Scocco GMacchioni PBajocchi Get alIs duplex ultrasonography useful for the diagnosis of giant-cell arteritis? Ann Intern Med2002;137:232-8. [PMID: 12186513] LinkGoogle Scholar
  • 24. Schultze DThomas YWunderli WEvaluation of an optical immunoassay for the rapid detection of influenza A and B viral antigens. Eur J Clin Microbiol Infect Dis2001;20:280-3. [PMID: 11399021] CrossrefMedlineGoogle Scholar