How accurately is euthanasia reported on death certificates in a country with legal euthanasia: a population-based study

Background Death certificates are the main source of information on the incidence of the direct and underlying causes of death, but may be unsuitable for monitoring the practice of medical assistance in dying, e.g. euthanasia, due to possible underreporting. This study examines the accuracy of certification of euthanasia. Methods Mortality follow-back survey using a random sample of death certificates (N = 6871). For all cases identified as euthanasia we checked whether euthanasia was reported as a cause of death on the death certificate. We used multivariable logistic regression analysis to evaluate whether reporting varied according to patient and decision-making characteristics. Results Through the death certificates, 0.7% of all deaths were identified as euthanasia, compared with 4.6% through the mortality follow-back survey. Only 16.2% of the cases identified from the survey were reported on the death certificate. Euthanasia was more likely to be reported on the death certificate where death was from cancer (14% covered), neurological diseases (22%) and stroke (28%) than from cardiovascular disease (7%). Even when the recommended drugs were used or the physician self-labelled the end-of-life decision as euthanasia, euthanasia was only reported on the death certificate in 24% of cases. Conclusions Death certificates substantially underestimate the frequency of euthanasia as a cause of death in Belgium. Mortality follow-back studies are essential complementary instruments to examine and monitor the practice of euthanasia more accurately. Death certificate forms may need to be modified and clear guidelines provided to physicians about recording euthanasia to ensure more accurate certification.