Table 4 Summary of findings against 14 methodological issues for feasibility research

1. What factors influenced eligibility and what proportion of those approached were eligible?

We identified modifiable and unmodifiable factors for inclusion eligibility.

Modifiable factor: inclusion age and incident ESKD. Changing the age cut-off and enrolling patients with prevalent ESKD augmented the rate of recruitment.

Unmodifiable factors: previous AV access surgery, poor prognosis, expired before surgical referral, and vasculature not suitable for fistula or graft placement.

Other: nephrology care located outside research sites (14 out of 159 patients screened). Involvement of other clinical sites will enhance recruitment.

2. Was recruitment successful?

Yes. Recruiting success was defined as ≥ 70% of eligible participants agreeing to participate and enroll in the study. Revised of inclusion and exclusion criteria facilitated recruitment.

A total of 81.5% of eligible participants agreed to participate and were enrolled in the study.

3. Did eligible participants consent?

Yes.

Forty-four (81.5%) out of 54 eligible patients consented to participate.

4. Were the participants successfully randomized?

Yes. Randomization procedures worked well.

Differences between the AVG-first group (intervention) and AVF-first group (control) are expected as may occur with small sample size.

5. Were blinding procedures adequate?

No. Blinding to intervention did not occur.

Blinding the study team members (e.g., PI, study coordinator, vascular surgeon) to the type of AV access placement was deemed infeasible due to the visible nature of the intervention.

6. Did participants adhere to the intervention?

Yes. Successful adherence to the intervention was defined as at least 80% of the participants receiving the AV access according to randomization arm.

Thirty-nine (88.6%) out of 44 patients randomized to AV access placement underwent surgery and received the index AV access (78.3% in the AVG group and 100% in the AVF group).

7. Was the intervention acceptable to the participants?

Yes. Acceptability was assessed as refusal of eligible patients to consent.

Nine (16.7%) out of 54 eligible patients refused study participation.

8. Was it possible to calculate intervention costs and duration?

An economic evaluation was not conducted as part of this study.

N/A

9. Were outcome assessments completed?

Reasons for non-completion of the questionnaires or 4MGS test included evaluation burden or inability to ambulate safely.

The completion rate for baseline and follow-up assessments of grip strength was 88.6-100.0%. Between 22.7-31.8% of the participants reported questionnaire fatigue and declined completion of baseline assessments for ADLs, IADLs, and/or KDQOL-SF 1.3. The protocol was amended to include 4MGS; for this test, we noted that about 60.0% of the participants could not have gait speed assessed due to severe baseline functional impairment.

10. Were outcomes measured those that were the most appropriate outcomes?

All outcomes were deemed appropriate and valid.

The main clinical outcomes included AV access primary failure rate, time to successful cannulation, and access-related complications.

11. Was retention to the study good?

Attrition rate was assessed as the proportion of participants who were consented for the study and then withdrawn or censored at transfer to other facility or refusal to remain in the study.

Four (9.1%) of the 44 participants were withdrawn from the study.

12. Were the logistics of running a multicenter trial assessed?

Yes. This pilot trial spanned across 16 dialysis units, two hospital centers (one academic tertiary center and one regional hospital), and three nephrology practices.

Overall, the logistics and study procedures were adequate and functional in most areas, and important insights were gained to inform the design and efficient conduct of the planned future multisite trial. These include the following: allowing a realistic timeframe for regulatory approval and site start-up; clear communication between the PI and stakeholders of different sites (nephrologists, vascular surgeons, vascular access coordinators, study coordinators, and dialysis unit managers); establish clarity over inclusion/exclusions and methodological approach; obtain approval and establish organization for performing study-specific assessments at the outpatient dialysis units; employment of a range of strategies to retain trial center engagement.

13. Did all components of the protocol work together?

The main components of both the study protocol and intervention worked well together.

Trial methodology—two-stage screening, evaluation of vein mapping results to determine final eligibility, and correspondence with the surgical team—was streamlined during this pilot trial.

14. Did the feasibility/pilot study allow a sample size calculation for the main trial?

No. A sample size calculation for a future RCT was not calculated

Our feasibility study did not provide a meaningful effect size estimate for planning a subsequent RCT. This is due to the imprecision inherent in data from small sample sizes.