The pragmatic approach
Despite the fact that the boundaries between explanatory and pragmatic trials can be blurred, there are tools available that can quantify the degree of pragmatism in clinical trials. PRECIS (Pragmatic-Explanatory Continuum Indicator Summary) was developed in 2009 both as a scoring system and a visual representation to assess pragmatic features of clinical trials. In 2015, PRECIS-2 (7) was launched, containing nine different domains with a score from 1 (very explanatory, optimal conditions), to 5 (very pragmatic, clinical setting). With such a comprehensive quantification, most trials will have pragmatic features, and very few will be exclusively explanatory or pragmatic. It is important for both clinicians and researchers to understand the potential inherent in pragmatic trials, the features that define the pragmatic trials and how pragmatic elements can be used in their own research.
In trials of new treatments, the most pragmatic approach would be to include all relevant patients who initiate contact with the health service, be it hospitals, outpatient clinics or primary healthcare services. Traditional explanatory trials will typically have a strict selection of patients, which reduces the generalisability to common clinical practice. The Norwegian national quality registries are unique resources for recruitment to pragmatic clinical trials in that they make it possible to include and follow up patients directly in the established registries, without the need for trial-specific follow-up visits (8).
If the objective is to investigate the treatment of patients with acute heart failure in various local hospitals, patients in highly specialised university hospitals cannot be included – and vice versa. In this case, it is desirable to conduct the trial as closely as possible to the common clinical practice. In this context, single-centre trials will have less information value and lower degree of pragmatism, especially if the trial results are to be applied to other clinical settings.
The pragmatic element is reduced if a trial requires specific training, resources or expertise that are not routinely available in the health service. The most pragmatic approach is to use personnel and resources that are already available in the health service. A new treatment can then be compared to a control group that receives the standard treatment. A drug trial can be pragmatic if, for example, the patients are randomised to a drug-based intervention or not, where the decision of dosage and choice of trial drug is left to the doctor responsible for treatment. An example of this is found in the Norwegian BETAMI trial (BEtablocker Treatment After Acute Myocardial Infarction) (9), where patients who have been revascularised after a myocardial infarction are randomised to either beta blocker treatment or not. The doctor responsible includes the patient in the trial and chooses the specific type of beta blocker and the dosage. The patients in the control group do not receive any placebo medication.
The opposite of this type of pragmatic trials will entail, for example, specific drugs in specific dosages and dose intervals, where the treatment effect is compared to a placebo control group.