TABLE 3

Associations between estimated Cmax of the antibiotics and microbiological response according to treatment regimena

Therapy typeCmax (μg/ml) by drugbFavorable responsesUnfavorable responsesUnivariate analysisMultiple logistic regressionc
OR (95% CI)PaOR (95% CI)P
DailyAZM0.24 (0.14–0.51)0.18 (0.08–0.35)1.53 (1.01–2.31)0.0451.58 (1.01–2.48)0.044
AZM ≥0.229/52 (55.8)12/25 (48.0)1.37 (0.53–3.56)0.5231.45 (0.52–4.04)0.476
AZM ≥0.421/52 (40.4)4/25 (16.0)3.56 (1.07–11.86)0.0393.98 (1.06–14.85)0.040
RIFd11.2 (7.4–15.1)13.7 (8.3–20.4)0.92 (0.64–1.34)0.6781.00 (0.66–1.52)0.989
RIF ≥8.036/52 (69.2)20/25 (80.0)0.56 (0.18–1.76)0.3240.68 (0.19–2.38)0.545
EMBd3.4 (1.8–4.6)2.4 (1.7–3.5)1.34 (0.79–2.25)0.2791.30 (0.73–2.31)0.367
EMB ≥2.037/52 (71.2)17/25 (68.0)1.16 (0.41–3.26)0.7771.14 (0.38–3.46)0.810
IntermittentAZMd0.65 (0.18–1.31)1.00 (0.18–1.44)0.84 (0.59–1.19)0.3220.85 (0.58–1.23)0.379
AZM ≥0.254/73 (74.0)12/16 (75.0)0.95 (0.27–3.30)0.9321.01 (0.27–3.72)0.991
RIFd11.2 (3.0–21.6)12.0 (6.5–19.5)0.87 (0.64–1.18)0.3820.93 (0.67–1.27)0.636
RIF ≥8.047/73 (64.4)11/16 (68.8)0.82 (0.26–2.62)0.7401.12 (0.33–3.84)0.861
EMBd,e3.5 (2.0–5.6)4.8 (3.0–6.6)0.65 (0.35–1.21)0.1770.63 (0.33–1.23)0.176
EMB ≥2.055/72 (76.4)14/16 (87.5)0.46 (0.10–2.24)0.3380.41 (0.08–2.13)0.291
  • a Data are presented as median (interquartile range) or number/total number (%). CI, confidence interval; OR and aOR, odds ratio and adjusted odds ratio, respectively.

  • b AZM, azithromycin; Cmax, peak plasma concentration; EMB, ethambutol; RIF, rifampin.

  • c In univariate and multiple logistic regression analyses, the Cmax of each drug was analyzed after log2 transformation.

  • d Adjusted for etiologic pathogen, fibrocavitary disease, positive sputum smear, and use of injectable drugs in patients with daily therapy and adjusted for etiologic pathogen and positive sputum smear in patients with intermittent therapy.

  • e One patient with favorable response had a missing Cmax value for EMB.