Parkinson's disease case ascertainment in prospective cohort studies through combining multiple health information resources.

Marije Reedijk,Roel C H Vermeulen,Robert A Verheij,Anke Huss,Petra H Peeters,Antonio Palazón-Bru

doi:10.1371/journal.pone.0234845

Marije Reedijk, Roel C H Vermeulen + Show 4 more

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https://doi.org/10.1371/journal.pone.0234845

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Abstract

Epidemiological evidence from prospective cohort studies on risk factors of Parkinson’s disease (PD) is limited as case ascertainment is challenging due to a lack of registries and the disease course of PD. The objective of this study was to create a case ascertainment method for PD within two prospective Dutch cohorts based on multiple sources of PD information. This method was validated using clinical records from the general practitioners (GPs). Face validity of the case ascertainment was tested for three etiological factors (smoking, sex and family history of PD). In total 54825 participants were included from the cohorts AMIGO and EPIC-NL. Sources of PD information included self-reported PD, self-reported PD medication, a 9 item screening questionnaire (Tanner), electronical medical records, hospital discharge data and mortality records. Based on these sources we developed a likelihood score with 4 categories (no PD, unlikely PD, possible PD, likely PD). For the different sources of PD information and for the likelihood score we present the agreement with GP-validated cases. Risk of PD for established factors was studied by logistic regression as exact diagnose dates were not always available. Based on the algorithm, we assigned 346 participants to the likely PD category. GP validation confirmed 67% of these participants in EPIC-NL, but only 12% in AMIGO. PD was confirmed in only 3% of the participants with a possible PD classification. PD case ascertainment by mortality records (91%), EMR ICPC (82%) and self-reported information (62–69%) had the highest confirmation rates. The Tanner PD screening questionnaire had a lower agreement (18%). Risk estimates for smoking, family history and sex using all likely PD cases were comparable to the literature for EPIC-NL, but not for smoking in AMIGO. Using multiple sources of PD evidence in cohorts remains important but challenging as performance of sources varied in validity.

Highlights

Parkinson’s disease (PD) is a neurodegenerative disease affecting a considerable part of the elderly population, with a prevalence of more than 2% in the population above 65 [1,2]
AMIGO participants are more often higher educated and less often current smokers compared to EPIC-NL participants
The number of participants for each information source of PD is shown in Table 2, which shows that after the Tanner score, hospital discharge register (HDR) and Electronic Medical Records (EMRs) are the most frequent PD information sources

Summary

Introduction

Parkinson’s disease (PD) is a neurodegenerative disease affecting a considerable part of the elderly population, with a prevalence of more than 2% in the population above 65 [1,2]. The prevalence of PD will likely increase in the coming years as the population ages and there are currently no disease modifying treatments. Idiopathic PD is thought to be caused by an interaction between aging, genetics, and environmental factors [4]. For example PD is more common among men than women and a lower risk is found among smokers in epidemiological studies [5,6]. Many epidemiological studies on PD use a case-control design, due to the gains in efficiency and statistical power, case-control studies may suffer from reverse causality and other biases such as retrospective recall of lifestyle factors. The lower risk of such biases in prospective cohort studies could make them an important additional resource for studying PD risk factors

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