Feasibility and acceptability of procedures for a pragmatic trial of reduced exertion, high-intensity interval training with nondiabetic hyperglycaemia patients within a national health service practice setting

Formal Medical Research Council guidance highlights the requirement for greater attention to be given to the initial development of healthcare interventions. This is relevant for exercise interventions since they are frequently shown to bring about intended effects under ideal circumstances, but fail to demonstrate effectiveness when translated to real-world contexts. The aim of this research was to carry out a feasibility study to describe and report data relevant to the acceptability of a reduced-exertion, high-intensity interval training (REHIT) intervention for non-diabetic hyperglycaemia (NDH) patients, delivered in a National Health Service practice setting. The purpose was to assess whether it would be appropriate to progress to a larger-scale pragmatic trial, and to optimise the design and conduct of any such trial. The intention was to recruit 40 participants from a single centre, which was considered adequate to
meet the objectives of the study. Patients were eligible to take part if they were diagnostically defined as NDH based on a glycated haemoglobin (HbA1c) value of 42–46 mmol· mol. The study revealed several issues including patient eligibility, challenges to recruitment, and poor clinician engagement. Ninety six patients were identified and screened for eligibility, but 51 were not eligible. The main reason was that 26 participants (27% of the total screened), since original diagnosis, were no longer within the diagnostic range for NDH with blood glucose control either having moved to overt type 2 diabetes or euglycaemia.
Despite the simplicity and convenience of using HbA1c to assess diabetes risk, the process of accurately screening and case finding eligible patients was problematic with just seven participants volunteering to take part in the study. Some aspects of the intervention worked well. Adherence to the exercise intervention was high, with 97% of sessions completed for the participants that finished the study (n = 6). The small sample limits interpretation of data, thus it is not possible to estimate variability of intended outcomes in a formal sample size calculation for a full-scale trial. Although the trial is not feasible in its current form, this preparatory stage of trial design pre-empted problems
with the intervention that could be changed to optimise the design and conduct of a larger-scale trial to improve transferability of REHIT into real-life scenarios. Solutions to the issues identified include using a dedicated local recruiter with a strong relationship among the patients and healthcare team, using participant incentives to take part, and allowing for a longer recruitment period. Interventions must also be sensitive to the built environment, socioeconomic factors, and the medical needs of individual patients. It follows that a compromise must be made between scientific robustness and generalisability to
routine real-world contexts.