Reasons for caution when evaluating health care interventions using non-randomised study designs

Forschende Komplementärmedizin und klassische Naturheilkunde = Research in complementary and natural classical medicine
B C Reeves

Abstract

The key difference between randomised (RCTs) and non-randomised studies (NRS) is their susceptibility to selection bias. Unlike RCTs, groups in non-randomised cohort studies are unlikely to be balanced because of the reasons leading patients to receive one or another treatment, giving rise to "confounding by clinical indication" (CCI). Researchers can try to minimise the susceptibility of NRS to selection bias both at the design stage, e. g. by matching participants on key prognostic factors, and during data analysis, e. g. by regression modeling. Nevertheless, because of i) logistical difficulties in matching, ii) imperfect knowledge about the relationships between prognostic factors and between prognostic factors and outcome, and iii) because of measurement limitations, it is inevitable that estimates of effect size derived from NRS will be confounded to some extent. Researchers and users of evidence alike need to be aware of the consequences of residual confounding. CCI need not necessarily lead to systematic bias in favour of one treatment but, if CCI acts in an unpredictable way, it will still give rise to additional, non-statistical "uncertainty bias" around the estimate of effect size.

Citations

Oct 29, 2008·Evidence-based Complementary and Alternative Medicine : ECAM·Renatus Ziegler
Feb 12, 2011·Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine·Alexander A HankePeter Kienbaum
Oct 24, 2006·Forschende Komplementärmedizin = Research in Complementary Medicine·Ronald Grossarth-Maticek, Renatus Ziegler
Aug 15, 2019·BMC Public Health·Yulia BlomstedtLars Weinehall
Jun 29, 2007·Forschende Komplementärmedizin = Research in Complementary Medicine·Ronald Grossarth-Maticek, Renatus Ziegler

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.

Related Papers

Forschende Komplementärmedizin und klassische Naturheilkunde = Research in complementary and natural classical medicine
B C Reeves, W Gaus
European Journal of Cancer : Official Journal for European Organization for Research and Treatment of Cancer (EORTC) [and] European Association for Cancer Research (EACR)
T J BenraadC G Sweep
© 2021 Meta ULC. All rights reserved