25-Year summary of US malpractice claims for diagnostic errors 1986–2010: an analysis from the National Practitioner Data Bank

BACKGROUND: We sought to characterise the frequency, health outcomes and economic consequences of diagnostic errors in the USA through analysis of closed, paid malpractice claims. METHODS: We analysed diagnosis-related claims from the National Practitioner Data Bank (1986-2010). We describe error type, outcome severity and payments (in 2011 US dollars), comparing diagnostic errors to other malpractice allegation groups and inpatient to outpatient within diagnostic errors. RESULTS: We analysed 350 706 paid claims. Diagnostic errors (n=100 249) were the leading type (28. 6%) and accounted for the highest proportion of total payments (35. 2%). The most frequent outcomes were death, significant permanent injury, major permanent injury and minor permanent injury. Diagnostic errors more often resulted in death than other allegation groups (40. 9% vs 23. 9%, p<0. 001) and were the leading cause of claims-associated death and disability. More diagnostic error claims were outpatient than inpatient (68. 8% vs 31. 2%, p<0. 001), but inpatient diagnostic errors were more likely to be lethal (48. 4% vs 36. 9%, p<0. 001). The inflation-adjusted, 25-year sum of diagnosis-related payments was US38. 8 billion (mean per-claim payout US386 849; median US213 250; IQR US74 545-484 500). Per-claim payments for permanent, serious morbidity that was 'quadriplegic, brain damage, lifelong care' (4. 5%; mean US808 591; median US564 300), 'major' (13. 3%; mean US568 599; median US355 350), or 'significant' (16. 9%; mean US419 711; median US269 255) exceeded those where the outcome was death (40. 9%; mean US390 186; median US251 745). CONCLUSIONS: Among malpractice claims, diagnostic errors appear to be the most common, most costly and most dangerous of medical mistakes. We found roughly equal numbers of lethal and non-lethal errors in our analysis, suggesting that the public health burden of diagnostic errors could be twice that previously estimated. Healthcare stakeholders should consider diagnostic safety a critical health policy issue.