Frequency of susceptibility, intermediate resistance and full resistance to NRTIs, NNRTIs and PIs: (a) global frequency; (b) frequency in patients on first-line therapy; and (c) frequency in patients on second-line therapy. The resistance results were classified into three categories: (i) high level of resistance (presence of mutations associated with drug resistance); (ii) intermediate resistance (presence of mutations associated with low level of resistance); and (iii) susceptible (absence of resistance mutations). NVP, nevirapine; EFV, efavirenz; RPV, rilpivirine; 3TC, lamivudine; FTC, emtricitabine; ZDV, zidovudine; d4T, stavudine; TDF, tenofovir; ABC, abacavir; ddI, didanosine; ATV, atazanavir; DRV, darunavir; IDV, indinavir; LPV, lopinavir; SQV, saquinavir.