Table 2 Nine PRECIS-2 domains for assessing trial designing characteristicsa
Domain | Assessment considerations |
|---|---|
Eligibility | To what extent are the participants in the trial similar to patients who would receive this intervention if it was part of usual care? For example, score 5 for very pragmatic criteria essentially identical to those in usual care; score 1 for a very explanatory approach with lots of exclusions (e.g., those who do not comply, respond to treatment, or are not at high risk for primary outcome, are children or elderly), or uses many selection tests not used in usual care |
Recruitment Path | How much extra effort is made to recruit participants over and above what would be used in the usual care setting to engage with patients? For example, score 5 for very pragmatic recruitment through usual appointments or clinic; score 1 for a very explanatory approach with targeted invitation letters, advertising in newspapers, radio plus incentives and other routes that would not be used in usual care. |
Setting | How different are the settings of the trial from the usual care setting? For example, score 5 for a very pragmatic choice using identical settings to usual care; score 1, for a very explanatory approach with only a single center, or only specialized trial or academic centersb |
Organization | How different are the resources, provider expertise, and organization of care delivery in the intervention group of the trial from those available in usual care? For example, score 5 for a very pragmatic choice that uses identical organization to usual care; score 1 for a very explanatory approach if the trial increases staff levels, gives additional training, require more than usual experience or certification and increase resources |
Flexibility in Delivery | How different is the flexibility in how the intervention is delivered from the flexibility anticipated in usual care? For example, score 5 for a very pragmatic choice with identical flexibility to usual care; score 1 for a very explanatory approach if there is a strict protocol, monitoring and measures to improve compliance, with specific advice on allowed co-interventions and complications |
Flexibility in Adherence | How different is the flexibility in how participants are monitored and encouraged to adhere to the intervention from the flexibility anticipated in usual care? For example, score 5 for a very pragmatic choice involving no more than usual encouragement to adhere to the intervention; score 1 for a very explanatory approach that involves exclusion based on adherence, and measures to improve adherence if found wanting. In some trials e.g., surgical trials where patients are being operated on or intensive care unit trials where patients are being given intravenously administered drug therapy, this domain is not applicable as there is no compliance issue after consent has been given, so this score should be left blank |
Follow-up | How different is the intensity of measurement and the follow-up of participants in the trial from the typical follow-up in usual care? For example, score 5 for a very pragmatic approach with no more than usual follow-up; score 1 for a very explanatory approach with more frequent, longer visits, unscheduled visits triggered by primary outcome event or intervening event, and more extensive data collection |
Primary Outcome | To what extent is the primary outcome of the trial directly relevant to participants? For example, score 5 for a very pragmatic choice where the outcome is of obvious importance to participants; score 1 for a very explanatory approach using a surrogate, physiological outcome, central adjudication or use assessment expertise that is not available in usual care, or the outcome is measured at an earlier time than in usual care |
Primary Analysis | To what extent are all data included in the analysis of the primary outcome? For example, score 5 for a very pragmatic approach using intention-to-treat with all available data; score 1 for a very explanatory analysis that excludes ineligible post-randomization participants, includes only completers or those following the treatment protocol |