Under-reporting of Parkinson's disease on death certificates: A population-based study (NEDICES)

Background: Parkinson's disease is frequently omitted as a cause of death from death certificates. A limitation of previous studies that attempted to assess the validity of death certificates is that population-dwelling cases, with milder, undiagnosed Parkinson's disease were likely excluded. As a result, those studies likely overestimated the validity of death certificates because they did not include these milder cases. We assessed the validity of death certificates in a prospective population-based study (NEDICES), which includes previously undiagnosed Parkinson's disease cases detected during the assessment Methods: 3926 community-dwelling elderly subjects with and without Parkinson's disease were followed during a median of 12.6 years, after which the death certificates of those who died were examined. We calculated the proportion of cases of clinically diagnosed Parkinson's disease for whom a diagnosis of Parkinson's disease was certified as the basic cause of death on death certificates. Results: 1791 (45.6%) of the 3926 participants died over a median follow-up of 7.1 years, including 82 (73.9%) deaths among 111 participants with Parkinson's disease. Parkinson's disease was rarely certified as the basic cause of death (14.6%). Gender, disease stage and the period during which the study was conducted (i.e., 1994 to 2007) did not influence the likelihood that Parkinson's disease would be reported. Conclusions: Our findings reinforce the notion that the reporting of Parkinson's disease on death certificates remains poor. This suggests a lack of awareness of the importance of Parkinson's disease as a cause of death. (C) 2014 Elsevier B.V. All rights reserved.