There is substantial variation in CoDs in HIV-infected persons according to sources and algorithms. ICD-10 in patients known to be HIV-positive overestimates HIV/AIDS-related deaths at the expense of underestimating liver-related diseases, infections and ill defined causes. CoDe seems as the best option for cohort studies.

In Spain it is imperative that there be systematic use of NDI data to supplement cancer registries, so that comparisons of relative survival rates between registries can be improved.