A possible artefactual component in specific cause mortality gradients. Social class variations in the clinical accuracy of death certificates

This paper investigates one possible avenue of artefactual influence on the production and/or concealment of social class gradients in specific cause mortality rates, namely, the possibility of social class biases in the accuracy of diagnosis of cause of death and the systematic misallocation of certain social groups to particular diagnoses. Information on this topic was obtained by matching occupational data gathered at death registration with data on the accuracy of diagnosis of cause of death (measured by diagnostic agreement between clinician and pathologist) collected in a prospective study of 1152 hospital necropsies. Extrapolation from these data to national mortality rates should be cautious, but it appears that in the majority of the most common causes of death grouped by ICD chapter (neoplasms, cerebrovascular and digestive) social class gradients would be steeper if mortality data were based on pathologists' rather than clinicians' diagnoses. Only in the respiratory chapter would the gradient be reduced, with the gradient in cardiovascular deaths unaffected.