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Referral bias in ALS epidemiological studies
Giancarlo Logroscino1,2, Benoit Marin1,2,3,4,5,6, Marco Piccininni2
1Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari "Aldo Moro", Bari, Italy.
Plos One
|April 17, 2018
Summary
Referral bias in Amyotrophic Lateral Sclerosis (ALS) clinical studies is evident. Patients in ALS tertiary centers are younger, have longer survival, and different onset patterns compared to the general ALS population.
Area of Science:
- Neurology
- Epidemiology
- Clinical Research
Background:
- Concerns exist regarding the representativeness of patients in Amyotrophic Lateral Sclerosis (ALS) tertiary centers compared to the general ALS population.
- The extent of referral bias in clinical studies for ALS remains largely unquantified.
Purpose of the Study:
- To assess the nature, extent, and impact of referral bias in Amyotrophic Lateral Sclerosis (ALS) studies.
- To compare characteristics of ALS patients from tertiary centers with those from population-based registries.
Main Methods:
- Utilized data from the EURALS consortium, including four European ALS population-based registries.
- Contrasted demographic and clinical characteristics of ALS patients diagnosed in tertiary referral centers with the entire ALS populations within the same geographical areas.
Main Results:
- Patients referred to ALS centers were younger (1.1–2.4 years difference).
- Referred patients showed a lower likelihood of bulbar onset and a higher proportion of familial antecedents.
- Patients in referral centers exhibited a longer survival rate (11%–15% increase) compared to the overall ALS population.
Conclusions:
- A trend for referral bias is observed in cohorts from ALS referral centers.
- Comparing tertiary center data with local registry data can help estimate referral bias.
- Studies using clinical cohorts require cautious interpretation; local registries can improve ascertainment.
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