Discussion
The main practical challenge of this trial has been the
identification and recruitment of participants, owing to
the nature of ureteric stone disease and the care pathway
for these patients within the NHS. The majority of patients
present to secondary care units via emergency departments,
often out of normal hours, and this is problematic
for site research staff, as there is no way of predicting
how, where and when these patients might seek treatment.
The availability of the clinical trial pharmacist
(often only during normal office hours) to dispense
trial medication has also had implications for recruitment.
In some cases, participants have volunteered to come back
and collect trial medication during pharmacy hours, but
there have been occasions where they have not complied
with this requirement.
As the trial has progressed, we have seen a lower than
expected response rate to the participant questionnaires.
Strategies to improve response rate have been employed,
including text-message pre-notification of questionnaire
delivery, email delivery of reminder questionnaires,
short- form questionnaires at 12 weeks (capturing the
EQ5D data only) and monetary incentives (unconditional
£5 gift voucher for UK high street stores) sent with the
12-week questionnaires. The impact of these will be
discussed in the full trial report.
Our choice of primary outcome measure, where stone
passage is defined as no further intervention required, is
a pragmatic one and encompasses patient (symptoms),
clinical (continued presence of stone), and healthcare
delivery aspects of stone treatment. Although previous
triallists have recorded stone-free rate as confirmed by
imaging techniques (for example, CTKUB, plain X-ray of
the kidney, ureter and bladder), we considered that
participants would not receive imaging as part of their
standard care in the NHS and that there are safety concerns
with asking them to undergo such procedures purely
to fulfil the requirements of the trial. Additionally,
stone-free rate confirmed by imaging does not allow
for a cost-effectiveness assessment, which will be key
to evaluating the effect of MET. Any possible centre and
other biases relating to outcome attribution and recording
should be mitigated by blinding of the participants and
healthcare professionals, randomization and the high
sample size of the trial.
Other than these problems, there have been no main
issues in conducting the SUSPEND trial. We advise
researchers considering studies in a similar setting to
consider carefully the practicalities of recruitment and
availability of research staff; both those involved in the
trial and those in supporting services (for example, the
clinical trial pharmacy).