Although the proportions of patients of African, Latin American and South-East Asian origin significantly increased from 1.7% (n=14) in the period before 1993 to 12.6% (n=75) in the period from 1993 onwards (P<0.0001), non-B subtypes markedly increased among Europeans from 1.9% (13 of 753) in the earlier period to 9.2% (48 of 522) in the later period (P<0.0001) (Fig. 2a). Overall, the proportions of heterosexuals and MSM increased from 23.5% (n=180) in the earlier period to 46.9% (n=280) in the later

period (P<0.0001) and from 17.3% (n=133) to 33.5% (n=200) (P<0.0001), respectively, while the proportion of IDUs decreased from 52.9% (n=406) to 13.7% (n=82) (P<0.0001). The proportion of heterosexuals carrying a non-B variant increased from 7.8% (14 of 180) to 28.9% (81 of 280) (P<0.0001) between the two study periods. An increase in the prevalence of non-B Rucaparib ic50 subtypes from 0.2% (one of 406) to 4.9% (four of 82) (P=0.003) and from 0.8% (one of 133) to 6.0% (12 of 200) (P=0.018) was observed in IDUs and MSM, respectively (Fig. 2b). The gender distribution did

not differ between the two periods [30.7% (n=236) and 30.2% (n=180) female, respectively]. A disproportionately high number of female patients was recorded among IDUs in both periods (data not shown). Nevertheless, female patients carrying non-B variants increased from 1.3% (three of 236) in the period up to 1993 to 31.1% (56 of 180) in the period next from 1993 onwards (P<0.0001) (Fig. 2c). The probability of acquiring a non-B subtype was also studied in drug discovery patients with complete demographic data (subset CD) (Table 2). In the univariate analysis, a strong association was found between African origin and non-B clades (94.8% of African people carried a non-B strain) (P<0.0001), even though

Europeans accounted for 49.6% of non-B-infected patients. The most prevalent risk category in subset CD was IDU (35.8%), followed by heterosexual (33.7%) and MSM (24.4%). Nonetheless, a highly disproportionate percentage of non-B-infected patients were heterosexual (77.2%; P<0.0001). In the CD subset, 69.5% of patients were male. The gender distribution differed between groups infected with non-B and B subtypes; patients harbouring a non-B strain showed a 1:1.1 male to female ratio compared with 2.5:1 for subtype B-infected individuals. Female gender was significantly associated with infection with a non-B strain (P<0.0001), as 14.2% of women (59 of 416) compared with 6.8% of men (64 of 948) were infected with a non-B variant. A comparison between subtype B- and non-B-infected patients showed a difference in median age (37 vs. 33 years, respectively) (P<0.0001), while CD4 cell count (310 vs. 324 cells/μL, respectively) and plasma viral load (4.04 vs. 4.2 log copies/mL) were comparable in the two groups. The year of diagnosis was significantly associated with the probability of acquiring a non-B clade, as 17.