Table 4. Comparison of key care cascade gaps for the diagnosis of drug-resistance before and after the implementation of improved molecular diagnostics for resistance beyond rifampicin.
Implementation of first-line MTBDRplus testing on Xpert rifampicin-resistant sputum to include smear-negatives and MTBDRsl testing on all sputum resulted in a greater proportion of patients receiving second-line DST, reduced reliance on culture, and reduced turnaround time. The Supplementary Methods contains more information on these periods. Data are median (IQR) or % (n/N).
| Retrospective period MTBDRplus only on smear-positives Second-line DST by pDST only |
Prospective period MTBDRplus and MTBDRsl irrespective of smear-status Second-line pDST still done |
|||||
|---|---|---|---|---|---|---|
| Overall (n=2938) | Smear-positive (n=1674) | Smear-negative (n=1264) | Overall (n=799) | Smear-positive (n=416) | Smear-negative (n=383) | |
| On treatment without receiving any second-line DST | 23 (668/2938) | 21 (357/1674) | 25 (311/1264) *p=0.358 |
5 (40/799) ^p<0.001 |
2 (7/416) ^p<0.001 |
9 (33/383) *p<0.001 ^p<0.001 |
| MTBDRplus direct testing | N/A | 100 (1674/1674) | N/A | 100 (799/799) | 100 (416/416) | 100 (383/383) |
| With an actionable result | N/A | 79 (1317/1674) | N/A | 99 (797/799) | 100 (416/416) | 99 (381/383) *p=0.140 |
| Without an actionable result | N/A | 21 (357/1674) | N/A | 0 (2/799) | 0 (0/416) | 1 (2/383) |
| MTBDRsl direct testing | N/A | N/A | N/A | 100 (799/799) | 100 (416/416) | 100 (383/383) |
| With an actionable result | N/A | N/A | N/A | 78 (622/799) | 91 (380/416) | 63 (242/383) *p<0.001 |
| Without an actionable result | N/A | N/A | N/A | 22 (177/799) | 9 (36/416) | 37 (141/383) *p<0.001 |
| Days-to-result (actionable or non-actionable) | N/A | N/A | N/A | 6 (5-7) | 6 (5-7) | 6 (5-7) *p<0.001 |
| MTBDRsl indirect testing | N/A | N/A | N/A | 22 (177/177) | 9 (36/36) | 37 (141/141) |
| With an actionable result | N/A | N/A | N/A | 22 (177/177) | 9 (36/36) | 37 (141/141) |
| Without an actionable result | N/A | N/A | N/A | 0 | 0 | 0 |
| Days-to-result (actionable or non-actionable) | N/A | N/A | N/A | 22 (16-26) | 16 (13-22) | 22 (18-27) *p=0.081 |
| pDST | 77 (2270/2938) | 79 (1317/1674) | 75 (953/1264) *p=0.358 | 94 (750/799) ^p<0.001 | 96 (400/416) ^p<0.001 | 91 (350/383) *p=0.500 ^p<0.001 |
| Days-to-result (IQR) | 37 (35-46) | 33 (29-38) | 42 (36-50) *p<0.001 | 30 (27-36) ^p<0.001 | 28 (25-35) ^p<0.001 | 34 (30-40) *p<0.001 ^p<0.001 |
| Overall, second-line DST | ||||||
| Patients who required second-line DST on isolates (indirect MTBDRsl or pDST) when direct MTBDRsl was non-actionable | 0 | 0 | 0 | 22 (177/799) | 9 (36/416) | 37 (141/383) *p<0.001 |
| Days-to-first actionable second line DST result (direct MTBDRsl, indirect MTBDRsl, or pDST) | 37 (35-46) | 33 (29-38) | 42 (36-50) *p<0.001 | 6 (5-7) | 6 (5-7) | 6 (5-7) *p<0.001 |
^
Comparisons within rows in “retrospective” vs “prospective” periods
*
Comparisons within rows and between columns by same smear status
Abbreviations and definitions: pDST-phenotypic drug susceptibility testing, IQR-interquartile range, n-number, N/A-non applicable, DST-drug susceptibility testing.