Mean time of drug exposure in months for each HIV-1 subtype-infected group.

£The antiretroviral drugs tenofovir and abacavir were not available to patients in the Public Health System at the time of survey
#Values left to the bar correspond to the total treated patients analyzed in the study; those at right represent patients which were only subjected to HAART therapy
*Comparative T-test values in bold are those significant at the 0.05 level