Who should code cause of death in a clinical trial?

Clinical trials of intervention in chronic disease often use cause-specific mortality as a principal outcome variable. Surprisingly, there has been little standardization of the approach to determining cause of death. Some studies use standard nosological coding based on the International Statistical Classification of Diseases while others rely on panels of physicians. Some studies utilize autopsy findings; others do not. There is a clear need for standardization, and a unified approach is suggested. In this approach, panels of physicians prepare death certificates and are trained and standardized to generate reproducible information. A system for adjudication of differences is a part of the trial's design. Death certificates are then transmitted to panels of nosologists who assign cause of death. Again, the nosologists are standardized, and an adjudication system for resolving differences is developed. This two-stage system takes advantage of strengths of the two types of cause of death coding now in use in clinical trials and should produce results permitting cross-trial and cross-time comparisons.