[How calcification in the atherosclerotic aorta can be associated with both a lower risk of recurrent stroke in clinical studies and an increased number of strokes in an autopsy study: interpretation based on selection bias].
Studies evaluating the role ofcalcification in the relationship between aortic atherosclerosis and stroke have led to contradictory conclusions: clinical studies show that aortic calcification is linked to a reduced risk of recurrence in stroke patients, while an autopsy series found a positive association between aortic calcification and stroke. The controversy can be explained by assuming that the risk associated with aortic atherosclerosis varies among individuals. Low-risk patients would live longer and have more time to develop calcification. Consequently, calcification would be a sign of low risk. This explains the apparent recurrence-reducing effect of calcification in stroke patients. The association between aortic calcification and stroke found in an autopsy series does not contradict this hypothesis but supports it: application of Berkson's fallacy shows that calcification is linked to lower mortality.
Van der Linden
J
J
Karolinska Universiteitsziekenhuis, afd. Thoraxchirurgie en Anesthesiologie, Stockholm, Zweden.
Van der Linden
W
W
D001013:Aorta, Thoracic / Q000473:pathology*; D001018:Aortic Diseases / Q000453:epidemiology* / Q000473:pathology; D050197:Atherosclerosis / Q000473:pathology*; D002114:Calcinosis; D006801:Humans; D012008:Recurrence; D012307:Risk Factors; D015983:Selection Bias; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology