Assessing recovery of renal function after tenofovir disoproxil fumarate discontinuation

Impaired renal function caused by tenofovir disoproxil fumarate (TDF) is considered reversible by discontinuing TDF administration, but there are occasional cases of incomplete recovery. We investigated the recovery of renal function after the discontinuation of TDF. Subjects comprised patients who had been started on TDF but in whom it was later discontinued because of impaired renal function. We investigated renal function until 96 weeks after the discontinuation of TDF, and the duration of TDF administration, up to May 2010. TDF was discontinued because of impaired renal function in 21 of 766 patients (2.7%). Following discontinuation, a significant recovery was seen in eGFR (p = 0.003). The median duration of administration was 28 days (6-941 days) in 9 patients whose eGFR recovered to pre-administration levels, 405 days (250-1,379) in 7 patients in whom mild recovery was seen, and 1,110 days (421-1,470) in 5 patients in whom eGFR was much lower than at the time of discontinuation. A significant correlation was seen between the eGFR recovery rate and the duration of TDF administration. TDF administration was discontinued because of renal impairment in 2.7% of patients. The duration of TDF administration was short in patients whose renal function recovered to pre-administration levels, but patients in whom sufficient recovery was not seen after discontinuation had received TDF over long periods and included many whose renal function gradually declined, even after discontinuation. Recovery of renal function after discontinuation of TDF is likely affected by the duration of TDF administration.