Creatinine clearance, reduced kidney function, and optimizing prescribing safety through practice feedback: a mixed methods study.

Background: Kidney function declines with age, increasing risk of harm from raised blood levels of many medicines. Prescribing is often inappropriate for older people with reduced creatinine clearance (CrCl).

Objective: To examine the feasibility and acceptability of providing performance feedback to increase CrCl calculation and coding and reduce potentially inappropriate prescribing.

Methods: We delivered evidence-based feedback on CrCl coding and prescribing for common medicines requiring dose adjustment in renal impairment. This mixed-methods study in seven UK general practices collected data at three time points for evidence-based feedback (October 2021, December 2021, February 2022) and additionally pre-/post-feedback intervention. An institutional ethnography explored responses. We observed and conducted semi-structured interviews with primary care clinicians. We thematically analysed qualitative data, guided by Clinical Performance Feedback Intervention Theory.

Results: Mean CrCl coding for ≥75s rose from 46% to 50.4% (difference 4.4%; range -10.5% to 14.7%). The number of patients with CrCl-associated inappropriate prescribing fell. We observed in 6 settings and interviewed 11 clinicians. Feedback engaged practices, was seen as important and allowed flexible action. All feedback cycle components were evident. Participants mentioned difficulties in remembering to consider kidney function, calculating and coding CrCl, recalling relevant medicines, and deciding appropriate dosing. Pharmacy teams were considered important facilitators in the response.

Conclusions: Feedback on prescribing in reduced kidney function can encourage improvement but is not sufficient alone. Systematized CrCl calculation and coding may improve patient safety by facilitating decision support for prescribing, review, and audit/research. A rigorous, larger-scale effectiveness evaluation is likely to be feasible and acceptable.