Trends in death certification for multiple sclerosis, motor neuron disease, Parkinson’s disease and epilepsy in English populations 1979–2006

Abstract

The objective of this study is to report trends in mortality, as certified on death certificates, from multiple sclerosis (MS), motor neuron disease (MND), primary Parkinson's disease (PD), and epilepsy, analysing not only the underlying cause of death but also all certified causes for each disease. Death records in the Oxford region, 1979-2006, and England, 1996-2006, were analysed for ascertaining the trends in mortality. The percentage of deaths coded as the underlying cause changed over time, coinciding with changes to the rules for selecting the underlying cause of death. Changes over time to coding rules had a large impact on apparent trends in death rates for PD when studied by underlying cause alone. They also had significant, though smaller, effects on trends in death rates for MS, MND and epilepsy. Nationally, in the last period of the study, underlying cause mortality identified 64% of deaths with a mention of MS, 88% of MND, 56% of PD, and 48% of epilepsy. In the longstanding Oxford data from 1979 to 2006, death rates based on all certified causes of death showed no significant change for MS; an upward trend for MND (notably in women over 75), though only in the last few years of the study; a significant but small decline for PD; and no significant change for epilepsy. When mortality statistics are analysed by underlying cause only, their value is reduced. A substantial percentage of neurological deaths are missed. Time trends may be misleading. All certified causes for each disease, as well as the underlying cause, should be analysed.

Birth Cohort Effects in Neurological Diseases: Amyotrophic Lateral Sclerosis, Parkinson’s Disease and Multiple Sclerosis

“…In ALS [26] , MS [27][28][29] , and PD [30] the registration level may be assumed to be quite high and to cover 60-90% of all patients. Of these, the percentage registered as underlying cause of death was 88% in ALS [21] , between 64% [21] and 83% [31] in MS, and 56% in PD [21] .…”

“…Firstly, several studies have argued for an increase in incidence and mortality rates from MS [13] , ALS [14][15][16][17][18] , and PD [19][20][21] in Western countries during the second half of the last century. Whether the trends in the time series might be due to predisposing factors, or, rather, to immediate factors (such as change of registration practice), is an issue open to further analysis.…”

Controlled population-based comparative study of USA and international adult [55-74] neurological deaths 1989-2014

“…Death rates depend upon the reliability of diagnosis, which some believe have resulted in higher specific diagnosis of ALS 14. However, as the measures are in the broad category of neurological diseases, this is less of a problem [1.5‐8].…”

“…Only country‐specific research could resolve this latter problem. The issue of reliability of diagnosis can be significant,14 but is largely resolved at the point of death in a global category such as “nervous disease deaths” 1, 5, 6, 7, 8. It is acknowledged that 100% accuracy can never be established, but as the WHO data are collected in a consistent and uniform system in these broad categories this is probably the most reliable and valid international data as yet available.…”

“…The rises in neurological mortality have been questioned as an artefact, for example, due to improved diagnosis of ALS14 and the effect of changing demographics giving rise to the “Gompertzian hypothesis.” This states that the neurological increases are a consequence of people living longer and therefore developing age‐related diseases that they had not lived long enough to develop previously 15, 16, 17. However, the diagnostic issue has limited impact as it is mortality rates that are measured not separate diagnostic categories, and at this point, there is little evidence of diagnostic uncertainty as the primary cause of death is categorized as being due to a neurological condition 1, 5, 6, 7, 8.…”