Table 6– Association of treatment success with the number of effective drugs used in the intensive and continuation phases of treatment by the multidrug-resistant tuberculosis (MDR-TB) patient group
Number of drugsMDR-TB onlyMDR-TB+INJrMDR-TB+FQrXDR-TB
Cases nAdjusted OR# (95% CI)Cases nAdjusted OR# (95% CI)Cases nAdjusted OR# (95% CI)Cases nAdjusted OR# (95% CI)
Intensive phase
 ≤2451.0 (reference)291.0 (reference)101.0 (reference)241.0 (reference)
 3621.1 (0.5–2.3)271.7 (0.5–5.2)321.0 (reference)471.0 (reference)
 41651.9 (1.0–3.7)831.3 (0.5–3.1)491.6 (0.7–3.8)461.9 (0.8–4.3)
 52961.7 (0.8–3.8)1371.2 (0.4–3.4)351.4 (0.3–6.4)361.8 (0.5–6.6)
 ≥63801.0 (0.5–1.8)1201.3 (0.5–3.3)271.1 (0.4–2.9)204.9 (1.4–16.6)
Continuation phase+
 ≤2771.0 (reference)461.0 (reference)351.0 (reference)271.0 (reference)
 31335.9 (3.1–11.0)3312.2 (3.4–44)272.5 (0.8–7.4)323.3 (1.3–8.5)
 42396.0 (2.8–13.1)1013.7 (1.7–8.2)273.1 (0.5–21.1)286.1 (1.4–26.3)
 ≥52334.7 (2.7–8.1)1003.1 (1.7–6.0)202.3 (0.7–7.2)172.3 (0.7–7.6)
  • MDR-TB: multidrug-resistant TB (resistance to at least isoniazid and rifampicin); MDR-TB only: MDR-TB, but susceptible to fluoroquinolones, amikacin/kanamycin and capreomycin (at least one second-line injectable drug tested); MDR-TB+INJr: MDR-TB plus resistance to amikacin/kanamycin and/or capreomycin, but susceptible to fluoroquinolones; MDR-TB+FQr: MDR-TB plus resistance to any fluoroquinolone, but susceptible to amikacin/kanamycin and/or capreomycin (at least one second-line injectable drug tested); XDR-TB: extensively drug-resistant tuberculosis (MDR-TB plus resistance to any fluoroquinolone and any second-line injectable drug (amikacin/kanamycin and/or capreomycin)). #: odds ratios of treatment success (cure and completion) versus treatment failure/relapse/death adjusted for age, sex, HIV infection, previous TB treatment, previous MDR treatment (treatment for >1 month with two or more second-line drugs) and extent of disease. See Methods and [17] for treatment outcome definitions. : the initial part of a course of treatment during which an injectable drug is given. +: the period immediately following the initial phase when no injectable drug is given. Only 18 studies provided information regarding drug susceptibility testing and the number of drugs in the intensive phase, while only 15 of these described the number of drugs in the continuation phase. Statistical significance is represented by bold type.