Meilia P, Herkutanto H, Freeman M, Zeegers M A Review of Causal Inference in Forensic Medicine Forensic Science, Medicine and Pathology 2020, in press Scienfitic concepts of causal analyses in disease and injury Prof. dr. Maurice Zeegers
[email protected] LAW AND EPIDEMIOLOGY Opiate Allergy Case 49 year old man with a prior history of Coronary Artery Disease and 9 stents undergoes knee replacement surgery Hx states “codeine allergy In recovery complains of severe pain, and surgeon rx morphine Nurse reminds doc of allergy Patient dies within 20 minutes of injection Defense – he died due to bad heart 1 20 1
[email protected] Query US National Inpatient Sample (NIS) Pull all cases 2000-2009 coded for prior opiate allergy in which there was an allergic reaction to an opiate Look for death rate Pull all cases 2000-2009 of knee replacement surgery with a history of CAD and stent placement Look for cardiac-associated death rate 1 20 2
[email protected] Results Opiate – 43/10,000 exposures (1 in 233) Cardiac – 4/10,000 surgeries (1 in 2500) This yields an Comparative Risk of 10.8 or Probability of Causation of 91% Hazard period The time the two competing causes overlap There was 20 minutes between injection and death The cardiac deaths took place over a week There are 504 20 minute periods in a week 1 20 3
[email protected] Results Thus, the competing base rate of death secondary to the heart problems during the 20 minute hazard period was (504 X 2500) = 1,260,000 The CRR of causation attributable