Medical Diagnostic Clinical Study

A Medical Diagnostic Clinical Study is a Clinical Study that is conducted to test and find procedures for diagnosing a disease or health condition.

AKA: Diagnostic Accuracy Clinical Study.
Context:
- It is (often) a Cross-Sectional Clinical Study.
- It can range from an Observational Clinical Study to being an Interventional Clinical Study.
- It can be designed to assess one or more diagnostic accuracy measures (e.g. accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio).
Example(s):
Counter-Example(s):
See: Medical Diagnosis, Medication, Drug Development, Medical Device, Phase II Clinical Trial, Clinical Trial Design, Decentralized Clinical Trial, Standards for Reporting of Diagnostic Accuracy Studies (STARD) Statement.

References

2021

(Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Glossary_of_clinical_research#D Retrieved:2021-12-11.
- Diagnostic trials
  - Refers to trials that are conducted to find better tests or procedures for diagnosing a particular disease or condition. Diagnostic trials usually include people who have signs or symptoms of the disease or condition being studied. (NLM)

2019

(Korevaar et al., 2019) ⇒ Daniel A. Korevaar, Gowri Gopalakrishna, Jeremie F. Cohen, and Patrick M. Bossuyt (2019). "Targeted test evaluation: a framework for designing diagnostic accuracy studies with clear study hypotheses". Diagnostic and Prognostic Research volume 3, Article number: 22.
- QUOTE: In diagnostic accuracy studies, study hypotheses are rarely pre-defined and sample size calculations are usually not performed, which may jeopardize scientific rigor and can lead to over-interpretation or “spin” of study findings. In this paper, we propose a strategy for defining meaningful hypotheses in diagnostic accuracy studies.

2016

(Cohen et al., 2012) ⇒ Jeremie F. Cohen, Daniel A. Korevaar, Douglas G. Altman, David E. Bruns, Constantine A. Gatsonis, Lotty Hooft, Les Irwig, Deborah Levine, Johannes B. Reitsma, Henrica C. W. de Vet, and Patrick M. M. Bossuyt (2016)."STARD 2015 guidelines for reporting diagnostic accuracy studies: explanation and elaboration". In: BMJ Open 2016;6:e012799. DOI:10.1136/bmjopen-2016-012799.
- QUOTE: Diagnostic accuracy studies are, like other clinical studies, at risk of bias due to shortcomings in design and conduct, and the results of a diagnostic accuracy study may not apply to other patient groups and settings. Readers of study reports need to be informed about study design and conduct, in sufficient detail to judge the trustworthiness and applicability of the study findings. The STARD statement (Standards for Reporting of Diagnostic Accuracy Studies) was developed to improve the completeness and transparency of reports of diagnostic accuracy studies. STARD contains a list of essential items that can be used as a checklist, by authors, reviewers and other readers, to ensure that a report of a diagnostic accuracy study contains the necessary information. STARD was recently updated. All updated STARD materials, including the checklist, are available at http://www.equator-network.org/reporting-guidelines/stard.

2014

(Thiese, 2014) ⇒ Matthew S. Thiese. (2014). “Observational and Interventional Study Design Types; An Overview.” In: Biochemia Medica (Zagreb). Journal, 24(2).
- QUOTE: A specific study design is the diagnostic accuracy study, which is often used as part of the clinical decision making process. Diagnostic accuracy study designs are those that compare a new diagnostic method with the current “gold standard” diagnostic procedure in a cross-section of both diseased and healthy study participants. Gold standard diagnostic procedures are the current best-practice for diagnosing a disease. An example is comparing a new rapid test for a cancer with the gold standard method of biopsy. There are many intricacies to diagnostic testing study designs that should be considered. The proper selection of the gold standard evaluation is important for defining the true measures of accuracy for the new diagnostic procedure. Evaluations of diagnostic test results should be blinded to the case status of the participant. Similar to the intention-to-treat concept discussed later in interventional studies, diagnostic tests have a procedure of analyses called intention to diagnose (ITD), where participants are analysed in the diagnostic category they were assigned, regardless of the process in which a diagnosis was obtained. Performing analyses according to an a priori defined protocol, called per protocol analyses (PP or PPA), is another potential strength to diagnostic study testing. Many measures of the new diagnostic procedure, including accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio can be calculated. These measures of the diagnostic test allow for comparison with other diagnostic tests and aid the clinician in determining which test to utilize.

2012

(Mallet et al., 2012) ⇒ Susan Mallett, Steve Halligan, Matthew Thompson, Gary S. Collins, and Douglas G. Altman (2012). "Interpreting diagnostic accuracy studies for patient care". In: BMJ 2012;345:e3999. DOI: 10.1136/bmj.e3999.
- QUOTE: A diagnostic test accuracy study provides evidence on how well a test correctly identifies or rules out disease and informs subsequent decisions about treatment for clinicians, their patients, and healthcare providers. The authors highlight several different ways in which data from diagnostic test accuracy studies can be presented and interpreted, and discuss their advantages and disadvantages.

2009

(Simundic, 2009) ⇒ Ana-Maria Simundic (2009). "Measures of Diagnostic Accuracy: Basic Definitions". In: EJIFCC, 19(4): 203–211.
- QUOTE: Diagnostic accuracy of any diagnostic procedure or a test gives us an answer to the following question: "How well this test discriminates between certain two conditions of interest (health and disease; two stages of a disease etc.)?". This discriminative ability can be quantified by the measures of diagnostic accuracy:
  - sensitivity and specificity,
  - positive and negative predicative values (PPV, NPV),
  - likelihood ratio,
  - the area under the ROC curve (AUC),
  - Youden's index,
  - diagnostic odds ratio (DOR)

Different measures of diagnostic accuracy relate to the different aspects of diagnostic procedure(...)

Measures of diagnostic accuracy are extremely sensitive to the design of the study. Studies suffering from some major methodological shortcomings can severely over- or under-estimate the indicators of test performance as well as they can severely limit the possible applicability of the results of the study. The effect of the design of the study to the bias and variation in the estimates of diagnostic accuracy can be quantified (...). STARD initiative published in 2003 was a very important step toward the improvement the quality of reporting of studies of diagnostic accuracy (...)