Lithium Point-of-Care Testing to Improve Adherence to Monitoring Guidelines and Quality of Maintenance Therapy: Protocol for a Randomised Feasibility Trial

Lithium is the first-line treatment for bipolar disorders and a first-line augmentation option for treatment-resistant unipolar depression. Due to its narrow therapeutic window and risk of toxicity, people taking lithium require regular blood testing to monitor lithium levels in the body. However, studies have reported that only half of lithium-treated patients receive adequate lithium monitoring. This protocol describes a trial that will test the feasibility and acceptability of a point-of-care (POC) lithium blood testing programme in patients with unipolar or bipolar affective disorders taking lithium as a maintenance treatment. The primary objectives are to establish whether testing the effectiveness of POC testing is feasible, by assessing recruitment, attrition, and adherence to monitoring guidelines compared to participants randomised to testing as usual; to test whether the programme is acceptable to patients; and to measure potential contamination bias. The secondary objectives are to examine changes in health-related quality of life, the use of healthcare services, and depressive and manic symptoms to inform the design of a larger multi-site randomised controlled trial (RCT). This feasibility RCT will recruit 80 participants with affective disorders who are taking lithium. Participants will be 1:1 randomised to either POC monitoring or monitoring as usual where they will be followed up at three research visits over 30 weeks. The proportion of patients meeting guidelines for lithium monitoring will be examined, alongside measures of acceptability, wellbeing, and health economic data. POC testing has the potential to significantly improve patient safety and satisfaction with lithium treatment.