Linee guida per l’interpretazione dei lavori
scientifici in ambito di technology assessment Prof.ssa Anna Rita Vestri Dipartimento di Medicina Sperimentale
Linee guida per l’interpretazione dei lavori
scientifici in ambito di technology assessment Prof.ssa Anna Rita Vestri Dipartimento di Medicina Sperimentale
A health technology assessment (HTA) is a research based, applied assessment of relevant available knowledge of problems, when applying technology in relation to health and disease.
HTA is related to research due to its methods, but is also related to planning, administration, and management due
to its focus on decision-making.
HTA can thus be seen as a bridge between a science paradigm and a policy paradigm.
To fulfil their aim, the central problem statements in an HTA must take their starting point in the needs of the decision-makers (and their advisers) for a documented basis for deciding whether or not to apply health technology and to what extent.
Health technology assessment considers the effectiveness, appropriateness and cost of technologies. It does this by asking four fundamental questions:
• Does the technology work?
• For whom?
• At what cost?
• How does it compare with alternatives?
The problem could be the introduction of a technological innovation, which needs to be studied in relation to other already presently applied technologies in the area (e.g. tomographic angiography (CTA) and magnetic resonance angiography (MRA) for evaluating native coronary arteries)
Or the problem could be that there are uncertainties about the basis of the use of commonly applied technologies in connection with a certain clinical problem (e.g. diagnostics and treatment)
A process or system of HTA
Identification of technologies
Selection of technologies most in need of
assessment (priority setting)
Assessment (primary data collection)
Synthesis
Combining primary and secondary data
Making recommendations about appropriate use
Dissemination of information
Implementation in policy and practice
Assessing diagnostic accuracy
Terminology in studies of diagnostic accuracy
Index test: The test under evaluation
Reference standard: The best available method for establishing the presence or the absence of the condition of interest
- A single method
- A combination of methods
– Laboratory tests, imaging tests and pathology,dedicated clinical follow-up of participants
Accuracy: The amount of agreement between the index test and the reference standard
Questo lo dico dopo è ridondante
Bias (systematic error)
A tendency to produce results that depart systematically from the 'true' results. Unbiased results are internally valid.
Internal validity (validity)
The degree to which the results of a study are likely to approximate to the 'truth'. It is a prerequisite for external validity.
External validity (generalisability, applicability)
The extent to which the effects observed in a study are applicable outside of the study (in routine practice).
STARD initiative
Standards for Reporting of Diagnostic Accuracy
25 recommendations
Aimed at promoting complete and accurate
reporting of studies of diagnostic accuracy
Allows to detect the potential for bias in
the study - Internal validity
Allows to assess the generalizability and
applicability of the results – External validity
The STARD checklist is divided into five major topics and six subsequent subtopics. The five major topics—
1) title,abstract, and keywords;
2) introduction;
3) methods;
4) results;
5) discussion—
provide suggestions for study design
and reporting of the results to improve the reader’s ability to identify and judge the methodological rigor of diagnostic accuracy studies.
Each of the six subsequent subtopics
further break down the elemental design for participants,test methods and application, statistical methods, and estimates of diagnostic accuracy. By using the checklist during
the design phase, researchers are less apt to incorporate fatal study errors such as recruitment or selection bias or overlap between the index test and reference test findings,
and readers are more likely to improve their critique of diagnostic accuracy study secondary to standardization of reporting and design.
The principal purpose of the STARD is to improve the quality of reporting of
diagnostic studies. STARD is designed to outline the specific features required for an unbiased diagnostic accuracy study and to improve the ability of the reader to gauge the strength of a finding through commonality in reporting.
Systematic reviews aim to identify and evaluate all available research evidence relating to a particular objective.
Quality assessment is an integral part of any systematic review.
If the results of individual studies are biased and these are synthesised without any consideration of quality then the results of the review will also be biased.
It is therefore essential that the quality of individual studies included in a systematic review is assessed in terms of potential for bias, lack of applicability, and, inevitably to a certain extent, the quality of reporting.
A formal assessment of the quality of primary studies included in a review allows investigation of the effect of different biases and sources of variation on study results.
Diagnostic accuracy studies allow the calculation of various statistics that provide an indication of "test performance"
– how good the index test is at detecting the target condition.
These statistics include sensitivity, specificity,positive and negative predictive values, positive and negative likelihood ratios, diagnostics odds ratios and receiver
operating characteristic (ROC) curves.
Unique design features mean that the criteria needed to assess the quality of diagnostic test evaluations differ from those needed to assess evaluations of therapeutic interventions.
It is also important to use a standardised
approach to quality assessment. This should avoid the choice of a quality assessment tool that is biased by preconceived ideas. Although several checklists for the assessment of the quality of studies of diagnostic accuracy exist, none of these have been systematically developed or evaluated, and they differ in terms of the items that they assess.
Comments