borderline significanceP = 0.06
Nonetheless, this continuous development of DRMs in patients starting ART since 2007 sets NNRTI apart from the other historical drug classes, where there is a decreasing trend; PI resistance for group IV in 2011 was significantly lower than expected (P = 0.04, chi-square test), and the same trend was seen for NRTI, although with borderline significance (P = 0.06, chi-square test).