During a median follow-up of 18 months ( interquartile range 12-27 months ) , mean within-group eGFR change from baseline was +0.14 mL/min/1 .73 m for TDF , -0.22 mL/min/1 .73 m for FTC-TDF , and +1.37 mL/min/1 .73 m for placebo , translating into average declines in eGFR attributable to PrEP vs placebo of -1.23 mL/min/1 .73 m ( 95 % CI , -2.06 to -0.40 ; P = .004 ) for TDF and -1.59 mL/min/1 .73 m ( 95 % CI , -2.44 to -0.74 ; P < .001 ) for FTC-TDF .