There is a large body of literature describing why patients may not want to participate in randomised controlled trials^1,2 but evidence related to pharmacy practice research is less well described. This work arises from a study of whether a pharmacist could improve the extent and quality of repeat prescribing in a population of patients aged 65 or older by running clinical medication review clinics. We wanted to know if the patients recruited were typical of the general population aged 65 years old or over, in terms of age, sex and number of repeat medicines and reasons why patients did not wish to participate.

Method
The 4 general practices recruited provided a list of all patients on repeat medicines over the age of 65. Patients were excluded if terminally ill, in a nursing or residential home or another clinical trial. A letter was written to all eligible patients to ask whether they would consent to be included in the study. The letter invited them to a consultation, with a pharmacist, at the general practice, to "see if a pharmacist can help the doctor by checking how people's medicines are working". Patients were written to a second time if they did not reply within 2 weeks. If no reply was received to the second letter, they were contacted by telephone.

Patients who were contacted by telephone and who did not wish to be involved were asked for their reasons. A qualitative analysis of these comments was performed to produce broad categories. In addition, the age, sex and number of repeat medicines of consenting and non- consenting patients was analysed and a comparison of the two groups was made to see if significant differences existed.

Results
There were 2,402 eligible patients, all of whom were contacted by letter. 1,194 (50%) agreed to participate. Patients who did not consent to be in the study were more likely to be older (odds ratio = 0.95, (95% CI 0.94, 0.96), p<0.0001), female (OR= 0.76 (0.64,0.89) p=0.001) and be on fewer repeat medicines (OR= 1.03 (1.0,1.0) p=0.01).

Nine broad categories of reasons why patients did not participate were identified from the telephone interviews: letter misunderstood/not readable, not contactable, confused, poor access to surgery, too unwell, mistrust of study objectives, concern about damaging relationship with GP, number of medicines thought to be too few, attitude to health care.

Discussion
There is evidence of reluctance by patients to take part in medication review³ and a consent rate of 50% for a trial of a novel review process raises doubts about generalisability. However, these results show that the reasons for non-consent are mainly related to the nature of the review, rather than because it was part of a research process. Non-consenting patients are older, more likely to be female and on fewer repeat medicines. Further research is needed to investigate barriers to pharmacists undertaking medication reviews.

References

1. Llewellyn-Thomas HA, McGreal MJ, Thiel EC, et al. Patients' willingness to enter clinical trials: measuring the association with perceived benefit and preferences for decision. Soc Sci Med 1991;32(1):35-42.
2. Britton A, McKee M, Black N, et al. Threats to applicability of randomised trials: ex-clusions and selective participation. J Health Serv Res Policy 1999 Apr;4(2):112-21.
3. Goodyear L, Lovejoy A, Nathan A, Warnett S. Brown Bag Medication Reviews in Community Pharmacies. Pharm J 1996;256:723-5