Table 2.
Frequency Distribution of Major NRTI Mutations
| No. (%) of NRTI regimen |
|||||||
|---|---|---|---|---|---|---|---|
| All (N=175) | TDF (N=23) | AZT (N=25) | d4T (N=36) | AZT/d4Tb (N=45) | AZT/d4T,TDFb (N=44) | p-valuea | |
|
NRTI mutations | |||||||
| M184V | 144 (83) | 14 (61) | 22 (88) | 29 (81) | 42 (93) | 36 (82) | 0.1 |
| K65R | 25 (14) | 13 (57) | 0 | 2 (6) | 0 | 10 (23) | <0.001 |
| V75I | 17 (10) | 1 (4) | 0 | 7 (19) | 6 (13) | 3 (7) | 0.03 |
| M184I | 12 (7) | 7 (30) | 0 | 1 (3) | 0 | 4 (9) | 0.001 |
| L74V | 5 (3) | 0 | 0 | 2 (6) | 1 (2) | 2 (5) | 0.5 |
| Y115F | 6 (3) | 3 (13) | 0 | 0 | 1 (2) | 2 (5) | 0.02 |
| Q151M | 6 (3) | 0 | 0 | 3 (8) | 1 (2) | 2 (5) | 0.2 |
| A62V | 5 (3) | 0 | 0 | 2 (6) | 2 (4) | 1 (2) | 0.5 |
| F116Y | 4 (2) | 0 | 0 | 2 (6) | 1 (2) | 1 (2) | 0.5 |
| F77L | 4 (2) | 0 | 0 | 1 (3) | 1 (2) | 2 (5) | 1.0 |
| K70E | 3 (2) | 2 (9) | 0 | 0 | 0 | 1 (2) | 0.1 |
| 69i | 1 (1) | 0 | 0 | 1 (3) | 0 | 0 | 1.0 |
|
TAMs | |||||||
| M41L | 53 (30) | 0 | 8 (32) | 11 (31) | 23 (51) | 11 (25) | 0.003 |
| T215Y | 48 (28) | 0 | 8 (32) | 8 (22) | 22 (49) | 10 (23) | 0.01 |
| D67N | 40 (23) | 0 | 9 (36) | 9 (25) | 15 (33) | 7 (16) | 0.002 |
| K70R | 40 (23) | 0 | 10 (40) | 10 (28) | 12 (27) | 8 (18) | 0.001 |
| T215F | 39 (22) | 0 | 7 (28) | 6 (17) | 14 (31) | 12 (27) | 0.01 |
| K219E | 19 (11) | 2 (9) | 3 (12) | 4 (11) | 8 (18) | 2 (5) | 1.0 |
| L210W | 15 (9) | 0 | 1 (4) | 2 (6) | 7 (16) | 5 (11) | 0.8 |
| K219Q | 12 (7) | 0 | 3 (12) | 4 (11) | 2 (4) | 3 (7) | 0.2 |
|
Multiple NRTI mutations | |||||||
| 0 | 10 (6) | 0 | 2 (8) | 4 (11) | 2 (4) | 2 (5) | 0.001 |
| 1 | 29 (17) | 9 (39) | 5 (20) | 5 (14) | 4 (9) | 5 (11) | |
| 2 | 42 (24) | 9 (39) | 3 (12) | 5 (14) | 9 (20) | 15 (34) | |
| 3 | 36 (21) | 5 (22) | 7 (28) | 7 (19) | 7 (16) | 10 (23) | |
| 4+ | 58 (33) | 0 | 8 (32) | 15 (42) | 23 (51) | 12 (27) | |
|
Multiple TAMs | |||||||
| 0 | 66 (38) | 21 (91) | 7 (28) | 13 (36) | 6 (13) | 18 (41) | <0.001 |
| 1 | 26 (15) | 2 (9) | 2 (8) | 3 (8) | 12 (27) | 7 (16) | |
| 2 | 38 (22) | 0 | 8 (32) | 12 (33) | 8 (18) | 10 (23) | |
| 3+ | 44 (25) | 0 | 8 (32) | 8 (22) | 19 (42) | 9 (20) | |
Note. NRTI, nucleoside reverse transcriptase inhibitor; TDF, tenofovir; AZT, zidovudine; d4T, stavudine; TAMs, thymidine analog mutations.
a
Comparison of AZT, d4T and TDF only groups using Pearson’s chi-square and Fisher’s exact test.
b
Multiple first-line regimens: AZT/d4T refers to switching from AZT to d4T or d4T to AZT; AZT/d4T TDF, refers to switching from AZT or d4T to TDF. One participant switched from TDF to AZT and was not included as a third category for multiple first-line regimens because of the small sample size (n=1).