The respective proportions of persons who developed a confirmed 25 % or greater eGFR decline from baseline by 12 and 24 months was 1.3 % and 1.8 % for TDF and 1.2 % and 2.5 % for FTC-TDF , and these frequencies were not statistically different from the confirmed decline in the placebo group ( 0.9 % and 1.3 % by 12 and 24 months , respectively ) .