Errors in the diagnostic process Hierarchy of Qualities in Medicine Frequency of diagnostic Errors Judgment under Uncertainty: Heuristics and Biases The Voytovich Solution Click to View Presentation

Hierarchy of Qualties in Medicine From patient‘s point of view Diagnostic Quality Therapeutic Quality Patient Satisfaction

Hierarchy of Qualties in Medicine Medical point of view Diagnostic Quality Therapeutic Quality Patient Satisfaction

Hierarchy of Qualities in Medicine und cognitive Processes Diagnostic Quality Therapeutic Quality Patient Satisfaction Skills Rules Knowledge

Frequency of diagnostic Errors Follow-up Autopsy Study Medizinische Klinik USZ Lancet 2000;355: Random Selection of 100 patients in each year Autopsy Rate above 90% until 1992, in the year 2002 Reduction to 53%, complete Autopsy Classification of diagnostic Errors according to Goldman

Classification of diagnostic errors Goldman et al NEJM 1983:380: Major diagnostic Errors –Class I: Knowledge of correct Diagnosis would have led to Survival –Class II: Knowledge of correct Diagnosis would not have affected Survival (too ill, no Treatment available) Minor diagnostic Errors –Class III: Missed Diagnosis but not cause of Death –Class IV: Occult, clinically not diagnosable Entity of epidemiological Interest eg Gallstones

Major Diagnostic Errors

Minor Diagnostic Errors

Class I+II vs. Class III+IV

Correct Diagnosis

Autopsy Rate and class I Errors over time Kaveh G et al, JAMA 2003: 289:

Frequency of class I Errors Klasse IAutopsie- Fehlerrate Medizin+ IPS (USZ) % 53% Med-IPS (Mayo-Clinic) % 33% Med-IPS (Paris) %53% Med-IPS (Leuven,Belgien) % 93% 32 Spitäler in USA % 30% Medizin (Boston, USA) % 40% Arch Int Med 2004:164;389; Mayo Clin Proc 2000:75:562; Ann Thorac Surg 1997:64:380; JAMA1987:258:339; Mayo Clin Proc. 2003;78: NEJM 1988:318;1249

Autopsy: Gold Standard for clinical Diagnosis? Pelletier et al J Gen Intern Med 1989:4;300-03

Autopsy: Gold standard for clinical diagnosis? Pelletier et al J Gen Intern Med 1989:4;300-03

Representativness –Similarity with „typical“ examples stored in memory Availability –Recent expierence, painful memory Adjustment and Anchoring –Stick to early hypotheses despite new information Judgment under Uncertainty: Heuristics and Biases Tversky and Kahneman Science 1974:185:

Cognitive Mechanisms of diagnostic Errors according to A.E. Voytovich* Omission Premature Closure Inadequate Synthesis Wrong Formulations * J Med Educ 1985:60;302-07

Omission Most frequent Error Decreases with Experience  Consequences –Delayed or missed Diagnosis

Premature Closure Independent of Experience Correlates with Confidence (ie Overconfidence) in Relation to the actual Case Reflects estimated Frequency of the diagnosed Disease  Consequences –Delayed or missed Diagnosis –Unnecessary Therapies –False Sense of Confidence if Error is not detected

Inadequate Synthesis Correlates with Experience  Consequences –Unnecessary Investigations –Delayed Treatment

Cognitive Mechanisms of diagnostic Errors according to A.E. Voytovich* Omission Premature Closure Inadequate Synthesis Wrong Formulations * J Med Educ 1985:60;302-07

Lancet 2000:355;

Major Diagnostic Errors

Sensitivity and Specificity 1-Sensitivity: Rate of missed Diagnoses (false negative rate) 1-Specificity: Rate of wrong Diagnoses (false positive rate)

Cardiovascular Diseases Sensitivity and Specificity 69% 85% 82% 86% 97% SensitivitätSpezifität p = 0.061p = 0.034

Lancet 2000:355;

Infectious Diseases Sensitivity and Specificity 25% 100% 67% 100% 86% 99% SensitivitätSpezifität nsp = 0.036

Neoplastic Diseases Sensitivity and Specificity 89% 92% 88% 97% 96% SensitivitätSpezifität ns

Difficulties in learning from Experience Lack of Search for and use of disconforming Evidence Lack of outcome Information Use of unaided Memory for coding, storing and retrieving outcome Information

Summary and Proposal Major diagnostic Errors occur despite an ever increasing repertory of diagnostic Procedures 85% of serious diagnostic Errors can only be detected by Autopsy Analysis of error mechanism can be helpful in the Discussion and Prevention of diagnostic Errors Minimum Autopsy rate of 30% along with a yearly Report on diagnostic Errors should be mandatory for Accreditation of medical Clinics