Developing a core outcome set for pharmacist interventions in chronic kidney disease: a Delphi study

Significant heterogeneity exists for the outcomes reported in research for pharmacist interventions in chronic kidney disease (CKD), limiting interpretation and increasing research waste. Currently, no intervention-specific core outcome set in nephrology exists. This study aimed to develop a core outcome set for pharmacist intervention research in CKD.

This study consisted of three phases: Phase 1) an international online survey and systematic review to long-list outcomes; Phase 2) an e-Delphi survey; and Phase 3) an online consensus workshop. In Phase 2, participants ranked these outcomes in terms of importance using the 9-point Likert scale over two rounds. We recruited a diverse range of pharmacists, researchers, other healthcare professionals, people living with CKD, and their family members/carers.

One hundred-nine participants completed Phase 1, of whom 90/109 (82.6%) were invited to Phase 2. Forty-two/90 (46.7%) participants completed Round 1 of the e-Delphi and 30/42 (71.4%) completed Round 2. Participants rated 65 outcomes identified from Phase 1. Following Phase 2, 25 outcomes reached the ≥75% threshold to form a provisional core outcome set. A final core outcome set comprising 23 outcomes was agreed and categorized into "Essential" (five outcomes) and "Important" tiers (18 outcomes).

This study established a core outcome set for pharmacy research in CKD, reflecting outcomes important to different stakeholder groups. The five "essential" outcomes ('Health-related quality of life [HRQoL]", "Kidney function", "Medication adherence", "Medication error", and "Medication use') should be consistently reported in all trials. This study addresses a gap in achieving consensus and improving the consistency of outcomes in pharmacy research in CKD.