Referral bias in ALS epidemiological studies

for EURALS

Research output: Contribution to journalArticle

Abstract

BACKGROUND: Despite concerns about the representativeness of patients from ALS tertiary centers as compared to the ALS general population, the extent of referral bias in clinical studies remains largely unknown. Using data from EURALS consortium we aimed to assess nature, extent and impact of referral bias.

METHODS: Four European ALS population-based registries located in Ireland, Piedmont, Puglia, Italy, and Limousin, France, covering 50 million person-years, participated. Demographic and clinic characteristics of ALS patients diagnosed in tertiary referral centers were contrasted with the whole ALS populations enrolled in registries in the same geographical areas.

RESULTS: Patients referred to ALS centers were younger (with difference ranging from 1.1 years to 2.4 years), less likely to present a bulbar onset, with a higher proportion of familial antecedents and a longer survival (ranging from 11% to 15%) when compared to the entire ALS population in the same geographic area.

CONCLUSIONS: A trend for referral bias is present in cohorts drawn from ALS referral centers. The magnitude of the possible referral bias in a particular tertiary center can be estimated through a comparison with ALS patients drawn from registry in the same geographic area. Studies based on clinical cohorts should be cautiously interpreted. The presence of a registry in the same area may improve the complete ascertainment in the referral center.

Original languageEnglish
Pages (from-to)e0195821
JournalPLoS One
Volume13
Issue number4
DOIs
Publication statusPublished - 2018

Fingerprint

epidemiological studies
Epidemiologic Studies
Referral and Consultation
Registries
France
Italy
Population
Ireland
clinical trials
demographic statistics
Tertiary Care Centers
Demography
Survival

Keywords

  • Aged
  • Amyotrophic Lateral Sclerosis/diagnosis
  • Bias
  • Delayed Diagnosis
  • Europe/epidemiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Public Health Surveillance
  • Referral and Consultation/statistics & numerical data
  • Registries
  • Tertiary Care Centers

Cite this

Referral bias in ALS epidemiological studies. / for EURALS.

In: PLoS One, Vol. 13, No. 4, 2018, p. e0195821.

Research output: Contribution to journalArticle

for EURALS. / Referral bias in ALS epidemiological studies. In: PLoS One. 2018 ; Vol. 13, No. 4. pp. e0195821.
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title = "Referral bias in ALS epidemiological studies",
abstract = "BACKGROUND: Despite concerns about the representativeness of patients from ALS tertiary centers as compared to the ALS general population, the extent of referral bias in clinical studies remains largely unknown. Using data from EURALS consortium we aimed to assess nature, extent and impact of referral bias.METHODS: Four European ALS population-based registries located in Ireland, Piedmont, Puglia, Italy, and Limousin, France, covering 50 million person-years, participated. Demographic and clinic characteristics of ALS patients diagnosed in tertiary referral centers were contrasted with the whole ALS populations enrolled in registries in the same geographical areas.RESULTS: Patients referred to ALS centers were younger (with difference ranging from 1.1 years to 2.4 years), less likely to present a bulbar onset, with a higher proportion of familial antecedents and a longer survival (ranging from 11{\%} to 15{\%}) when compared to the entire ALS population in the same geographic area.CONCLUSIONS: A trend for referral bias is present in cohorts drawn from ALS referral centers. The magnitude of the possible referral bias in a particular tertiary center can be estimated through a comparison with ALS patients drawn from registry in the same geographic area. Studies based on clinical cohorts should be cautiously interpreted. The presence of a registry in the same area may improve the complete ascertainment in the referral center.",
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T1 - Referral bias in ALS epidemiological studies

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AU - Logroscino, Giancarlo

AU - Marin, Benoit

AU - Piccininni, Marco

AU - Arcuti, Simona

AU - Chiò, Adriano

AU - Hardiman, Orla

AU - Rooney, James

AU - Zoccolella, Stefano

AU - Couratier, Philippe

AU - Preux, Pierre-Marie

AU - Beghi, Ettore

PY - 2018

Y1 - 2018

N2 - BACKGROUND: Despite concerns about the representativeness of patients from ALS tertiary centers as compared to the ALS general population, the extent of referral bias in clinical studies remains largely unknown. Using data from EURALS consortium we aimed to assess nature, extent and impact of referral bias.METHODS: Four European ALS population-based registries located in Ireland, Piedmont, Puglia, Italy, and Limousin, France, covering 50 million person-years, participated. Demographic and clinic characteristics of ALS patients diagnosed in tertiary referral centers were contrasted with the whole ALS populations enrolled in registries in the same geographical areas.RESULTS: Patients referred to ALS centers were younger (with difference ranging from 1.1 years to 2.4 years), less likely to present a bulbar onset, with a higher proportion of familial antecedents and a longer survival (ranging from 11% to 15%) when compared to the entire ALS population in the same geographic area.CONCLUSIONS: A trend for referral bias is present in cohorts drawn from ALS referral centers. The magnitude of the possible referral bias in a particular tertiary center can be estimated through a comparison with ALS patients drawn from registry in the same geographic area. Studies based on clinical cohorts should be cautiously interpreted. The presence of a registry in the same area may improve the complete ascertainment in the referral center.

AB - BACKGROUND: Despite concerns about the representativeness of patients from ALS tertiary centers as compared to the ALS general population, the extent of referral bias in clinical studies remains largely unknown. Using data from EURALS consortium we aimed to assess nature, extent and impact of referral bias.METHODS: Four European ALS population-based registries located in Ireland, Piedmont, Puglia, Italy, and Limousin, France, covering 50 million person-years, participated. Demographic and clinic characteristics of ALS patients diagnosed in tertiary referral centers were contrasted with the whole ALS populations enrolled in registries in the same geographical areas.RESULTS: Patients referred to ALS centers were younger (with difference ranging from 1.1 years to 2.4 years), less likely to present a bulbar onset, with a higher proportion of familial antecedents and a longer survival (ranging from 11% to 15%) when compared to the entire ALS population in the same geographic area.CONCLUSIONS: A trend for referral bias is present in cohorts drawn from ALS referral centers. The magnitude of the possible referral bias in a particular tertiary center can be estimated through a comparison with ALS patients drawn from registry in the same geographic area. Studies based on clinical cohorts should be cautiously interpreted. The presence of a registry in the same area may improve the complete ascertainment in the referral center.

KW - Aged

KW - Amyotrophic Lateral Sclerosis/diagnosis

KW - Bias

KW - Delayed Diagnosis

KW - Europe/epidemiology

KW - Female

KW - Humans

KW - Male

KW - Middle Aged

KW - Public Health Surveillance

KW - Referral and Consultation/statistics & numerical data

KW - Registries

KW - Tertiary Care Centers

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DO - 10.1371/journal.pone.0195821

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