The need for standardised outcomes in pharmacist interventions in chronic kidney disease: a systematic review of randomised controlled trials
Authors: Ardavani A , Curtis F , Khunti K , Wilkinson T J , Highton P 
Published: November 2023

Abstract

Introduction
People living with chronic kidney disease (CKD) have a high prevalence of polypharmacy. Polypharmacy presents a significant burden and the risk of inappropriate prescribing in people with CKD is a cause for concern due to age-related changes associated with pharmacodynamics (e.g., increased sensitivity towards adverse drug events) and pharmacokinetics (e.g., reduced renal excretion)1. Strategies for the successful management of CKD include controlling cardiovascular risk factors, lifestyle modifications, and treating comorbidities. There is an ever-increasing role of pharmacists in managing CKD, from medication reviews to optimising risk factors2. However, currently, there is a lack of quality data on the impact of pharmacists in CKD management; this is partly due to the wide range of variable outcomes used in studies and a lack of standardised outcome reporting.

Aim
We aimed to explore the range of outcomes and measures used in pharmacist-led research in CKD that could be recommended for standardised use.

Methods
A systematic review of randomised controlled trials (RCTs) of interventions in a CKD population with significant pharmacist input was conducted. Searches were conducted in the following databases: MEDLINE, Scopus, and Web of Science. Databases were searched until January 2022; searches were re-run in February 2023. Data was extracted pertaining to clinical (e.g., mortality), economic (e.g., healthcare-associated costs), and humanistic (e.g., quality of life (QoL)) outcomes. Ethical approval was not required because this review is based exclusively on published literature.

Results
38 reports of 32 RCTs were identified, with sample sizes of RCTs ranging from 24 to 32,917 participants. Most studies were conducted in the United States (16/32), whilst one was conducted in the United Kingdom. Of these, 12/32 (37.5%) were exclusively conducted in people on dialysis, six in kidney transplant recipients, 13 in those with non-dialysis dependent CKD, and one study in a mixed cohort. The interventions delivered by pharmacists were heterogenous and included medicine reconciliation, patient counselling, and dose adjustment. A wide range of outcomes were reported including blood pressure, CKD progression, and QoL. The most frequently reported outcome was blood pressure, which was used as an endpoint in 12/32 (37.5%) studies. There was significant heterogeneity in the measures and methods used for reported outcomes. For example, in 11/32 studies (34.4%) where medication adherence was assessed, five separate outcome measures were used: variations of the Morisky Medication Scale (6/11), pharmacy refill records (2/11), Basel Assessment of Adherence to Immunosuppressive Medication Scale (1/11), a comparison of the quantity of medications prescribed with those present in containers (1/11), and the endstage renal disease adherence questionnaire (1/11).

Discussion/Conclusion
Nephrology is well adept in the use of standardised core outcome sets (COS) (e.g., the Standardised Outcomes in Nephrology initiative)3, yet such COS may not be appropriate to more specialist interventions where different or more relevant outcomes may be needed. The plethora of outcome measures identified in our review suggests a better standardisation of reporting is needed to facilitate consolidation of pharmacy research in the area and further support for the role of the pharmacist in CKD management.

References
1. Sera LC, McPherson ML. Pharmacokinetics and Pharmacodynamic Changes Associated with Aging and Implications for Drug Therapy. Clin Geriatr Med. 2012 May 1;28(2):273–86.
2. McKinnon A. Practice Spotlight: Pharmacist in a Chronic Kidney Disease Clinic. Can J Hosp Pharm. 2010;63(6):453.
3. Tong A, Manns B, Hemmelgarn B, Wheeler D, Evangelidis N, Tugwell P, et al. Establishing Core Outcome Domains in Hemodialysis: Report of the Standardized Outcomes in Nephrology−Hemodialysis (SONG-HD) Consensus Workshop. Am J Kidney Dis. 2017 Jan 1;69(1):107.