BACKGROUND:
Early
identification of patients with drug-resistant tuberculosis (DR-TB) increases
the likelihood of treatment success and interrupts transmission.
Resource-constrained settings use risk profiling to ration the use of drug
susceptibility testing (DST). Nevertheless, no studies have yet quantified how
many patients with DR-TB this strategy will miss.
METHODS:
A total
of 1,545 subjects, who presented to Lima health centres with possible TB
symptoms, completed a clinic-epidemiological questionnaire and provided sputum
samples for TB culture and DST. The proportion of drug resistance in this
population was calculated and the data was analysed to demonstrate the effect
of rationing tests to patients with multidrug-resistant TB (MDR-TB) risk
factors on the number of tests needed and corresponding proportion of missed
patients with DR-TB.
RESULTS:
Overall,
147/1,545 (9.5 %) subjects had culture-positive TB, of which 32
(21.8 %) had DR-TB (MDR, 13.6 %; isoniazid mono-resistant,
7.5 %; rifampicin mono-resistant, 0.7 %). A total of 553 subjects
(35.8 %) reported one or more MDR-TB risk factors; of these, 506
(91.5 %; 95 % CI, 88.9-93.7 %) did not have TB, 32/553
(5.8 %; 95 % CI, 3.4-8.1 %) had drug-susceptible TB, and only
15/553 (2.7 %; 95 % CI, 1.5-4.4 %) had DR-TB. Rationing DST to
those with an MDR-TB risk factor would have missed more than half of the DR-TB
population (17/32, 53.2 %; 95 % CI, 34.7-70.9).
CONCLUSIONS:
Rationing
DST based on known MDR-TB risk factors misses an unacceptable proportion of
patients with drug-resistance in settings with ongoing DR-TB transmission.
Investment in diagnostic services to allow universal DST for people with
presumptive TB should be a high priority.
Below: Symptomatic patients with multidrug-resistant tuberculosis risk factors for each group
Below: Percentages of drug-resistant tuberculosis patients detected by testing strategies
By: Martin LJ1,2, Roper MH3, Grandjean L3,4,5, Gilman RH3,6, Coronel J3, Caviedes L3, Friedland JS4, Moore DA3,5,6.
- 1Laboratorio de Investigación de Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, San Martín de Porras, Lima, Peru. martin.lauraj@gmail.com.
- 2Section of Infectious Diseases & Immunity & Wellcome Trust Imperial College Centre for Clinical Tropical Medicine, Imperial College London, London, UK. martin.lauraj@gmail.com.
- 3Laboratorio de Investigación de Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, San Martín de Porras, Lima, Peru.
- 4Section of Infectious Diseases & Immunity & Wellcome Trust Imperial College Centre for Clinical Tropical Medicine, Imperial College London, London, UK.
- 5LSHTM TB Centre and Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK.
- 6Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
- BMC Med. 2016 Mar 23;14(1):30. doi: 10.1186/s12916-016-0576-8.
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