RADAR1- Trial of a New Blood Sample Method (Remote Arthritis Disease Activity MonitoR)

In an arthritis patient population living some distance from hospitals, collection of a series of blood samples to monitor disease activity in a timely fashion is difficult. The ability to monitor markers of inflammation, such as C-reactive protein (CRP) and gauge a patient's response to treatments via disease activity score (i.e. DAS28-ESR) is not just important in early stage disease but also in patients with established disease. Patients with chronic disease tend to lose self-confidence in managing their condition and a substantial proportion can suffer recurrent disease flare- ups. These flare-ups are costly in terms of appointments with GP and specialist clinics and result in significant work disability.

Being able to reliably define and report a disease 'flare' in arthritis is currently problematic as there are no objective measures available to the patient while at home. The clear definition of a flare, as determined through blood testing would help justify an increase in immunosuppressant dose or a course of steroids. Currently, patients make a visit to their GP or hospital clinic, at 6 week intervals at best. In reality, this means that opportunities to monitor CRP during an active 'flare' are often missed and an informed intervention (medication adjustments) is not possible. Home monitoring is constrained by the costs of making phlebotomists available to make frequent home visits to patients. Also for markers which are unstable at ambient temperatures, blood samples need to be refrigerated and rapidly transported to the laboratory for analysis.

Thus the ability for the patient to collect their own blood samples in their own home and send these at ambient temperature to a laboratory would enable 'remote' and timely monitoring of chronic disease. The investigators have recently completed an Arthritis Research UK funded clinical study that demonstrated that a number of clinically relevant proteins related to flares (i.e.?) were reliably collected, stored for less than three months and extracted from dried blood spots (n=20 arthritis patients). The paper cards used to collect blood droplets were pre-treated to stabilise proteins and minimise haemolysis contamination (caused by bursting and breakdown of red blood cells). Our results across 20 arthritis patients revealed that 90% recovery rates can be achieved from dried blood spot sample (DBSS) stored at room temperature for 3 month (relative to a matched -20'C frozen plasma sample). The inflammation marker proteins included C-reactive protein (CRP), tumour necrosis factor alpha and Immunoglobulin G. Without pre-treatment of the DBSS paper, only 53% of these proteins are recovered.

For the patient, use of DBSS means that GP and hospital visits to take blood and carry out tests could be reduced. With minimal training, samples would be obtained simply at home by the patient, over a six week period and then transported at room temperature using conventional post. Proteins could then be analysed at a central lab. In the future, the technology could accompany patient assessments of disease activity and complement ongoing studies focused on wearable sensors to measure joint movement and stiffness (UU Data-glove project).

For the hospital trust, use of this novel technology could obviate the need for patients to attend the clinic for blood sampling. Soon after prescribing a new treatment, clinicians could use DBSS to monitor treatment efficacy in reducing inflammation. This technology therefore offers an earlier opportunity than currently available to titre dosage and switch from ineffective drugs or treatments associated with adverse events. Furthermore, feedback of the monitoring information provided by DBSS could be given to the patient, via for example smartphone application, and has the potential to improve adherence to treatment plans.