Core outcome set for pharmacist interventions in chronic kidney disease

Pharmacists are suitably placed as healthcare professionals in multidisciplinary teams to manage people with chronic kidney disease (CKD). However, several systematic reviews of studies have demonstrated that there is a significant heterogeneity in outcomes and outcomes measures of pharmacist interventions in CKD^​1–4​. Consequently, the wide range of outcomes results in increased research waste, limits research synthesis and the ability to compare and interpret findings. Moreover, many outcomes often measured in studies do not reflect outcomes that are important from the patient’s perspective^​5​.

To address this, a core outcome set (COS) can be developed, which is an agreed minimum number of outcomes that should be measured in every study for a particular clinical topic^​6​. A COS reflects outcomes that are important to various stakeholders such as healthcare professionals, patients and researchers^​7,8​. Its use helps to support research synthesis, reducing heterogeneity and reporting bias, as well as ensuring that the most important outcomes are evaluated^​7,8​.

An international e-Delphi consensus study was conducted, which consisted of three phases:

• Phase one — the generation of a long-list outcomes for evaluation via a systematic review and online survey;
• Phase two — a two-round e-Delphi survey;
• Phase three — an online consensus workshop. 

In phase two, participants were asked to rate outcomes in terms of importance using a nine-point Likert scale over two rounds. Participants consisted of pharmacists, researchers, other healthcare professionals, people living with CKD and their family members/carers.

Results

A total of 109 participants completed phase 1, of whom 90 (82.6%) were invited to phase 2. A total of 42 participants (46.7%, n=90) completed round 1 of the e-Delphi consensus study and 30 participants (71.4%, n=42) completed round 2. Participants rated 65 outcomes identified from phase 1. Following phase 2, 25 outcomes reached the ≥75% threshold to form a provisional COS. A final COS comprising 23 outcomes was established and categorised into ‘Essential’ (five outcomes) and ‘Important’ tiers (18 outcomes).

Conclusions

This study established a COS for pharmacy research in CKD, reflecting outcomes important to different stakeholder groups. The five ‘essential’ outcomes — health-related quality of life, kidney function, medication adherence, medication error and medication use — should be consistently reported in all future studies. For researchers and other healthcare professionals involved in the design and evaluation of studies of pharmacist interventions in CKD, the COS can enable comparisons to be made of interventions, further evidence synthesis and improve the consistency in outcome measurement.

Ashkon Ardavani, MPharm, MSc, PhD, General Pharmaceutical Council-registered pharmacist