A total of 779 patients completed the questionnaire (86% of eligible patients). Five hundred and ninety-one (75.9% of 779) participants were prescribed antiretroviral therapy (ART). Four hundred and thirty (55.2% of 779) participants had stopped or switched treatments and were eligible for inclusion, of whom 217 (50.5% of 430) fully completed the Concordance Scale. A subset of 160 (73.7% of 217) participants gave consent for the linkage with clinic data. The demographics of this group were comparable to those of the group who did not give consent. Of the 217 participants, 32 (14.7%) AZD6244 were female, 14 (6.5%) were heterosexual male

and 166 (76.5%) were homosexual male; 165 (76%) were White and 48 (22.1%) CT99021 mw non-White (Black-African, Asian or mixed/other); 27 (12.4%) had moved to the United Kingdom within the last 5 years and 103 (47.5%) were university educated. The mean age was 41.5 years [standard deviation (SD) 7.6]. In terms of treatment status, 70 (32.3%) had switched treatment once and 113 (52.1%) multiple times. Overall, 34 (15.7%) had stopped treatment (either now or in the past) and 20 (9.2%) had currently stopped treatment. The mean CD4 count was 521.84 cells/μL (SD 239.34 cells/μL; n=143) and 112 (79.4% of 141) had a VL≤50 HIV-1 RNA copies/mL. In terms of differences between

patients who fully completed the scale (n=217) and those who did not (n=213), White patients (χ2=6.98, P=0.008), homosexual men (χ2=19.49, P<0.001), those who were university educated Tacrolimus (FK506) (χ2=4.87, P=0.027) and those born in the United Kingdom (χ2=10.46, P=0.001) were more likely to complete the scale, as were patients with higher CD4 cell count (Mann–Whitney U=7580, P=0.015) and lower VL (Mann–Whitney U=7393, P=0.013). Higher completion rates were observed for those on treatment than

for those who had stopped (χ2=7.60, P=0.006), and differences in terms of CD4 cell count and VL disappeared once this factor was controlled for using linear (for CD4 cell count) and logistic (for VL≤50 copies/mL) regressions. In addition, patients who completed the scale were less likely to report playing a part in the decision to switch or stop (Mann–Whitney U=15049.5, P=0.016). There were no differences between patients who fully completed the questionnaire and those who did not on other measures, including symptom scores. In order to ensure that concordance ratings did not differ between full completers (n=217) and partial completers (n=118), Mann–Whitney U-tests were carried out on the individual Concordance Scale items to examine differences between these two groups. On nine of the 10 items there were no significant differences in the rating scores, indicating that partial completers were no different from full completers in their ratings.