Table 2

Primary and secondary outcome measures for this study

DrugEstimated change from placebo
Baseline adjusted estimate (95% CI), p valueFully adjusted* estimate (95% CI), p value
Bacterial load by quantitative culture (log10 cfu/mL)
 Moxifloxacin−0.32 (−0.81 to 0.17) p=0.20−0.42 (−0.91 to 0.08) p=0.10
 Doxycycline−0.05 (−0.50 to 0.40), p=0.82−0.11 (−0.55 to 0.33), p=0.62
 Azithromycin−0.17 (−0.62 to 0.29), p=0.47−0.08 (−0.54 to 0.38), p=0.73
Bacterial load by 16S qPCR (log10 copies/g of sputum)
 Moxifloxacin0.14 (−0.42 to 0.69), p=0.630.30 (−0.30 to 0.89), p=0.33
 Doxycycline0.06 (−0.49 to 0.60), p=0.840.16 (−0.40 to 0.72), p=0.58
 Azithromycin0.28 (−0.27 to 0.83), p=0.330.32 (−0.24 to 0.88), p=0.27
FEV1, mL
 Moxifloxacin39 (−84 to 161), p=0.5458 (−74 to 190), p=0.39
 Doxycycline31 (−89 to 151), p=0.6139 (−85 to 162), p=0.54
 Azithromycin1 (−123 to 124), p=0.99−1 (−126 to 125), p=0.99
SGRQ total score
 Moxifloxacin−2.25 (−8.60 to 4.09), p=0.49−1.88 (−8.59 to 4.84), p=0.59
 Doxycycline0.88 (−5.30 to 7.06), p=0.781.02 (−5.28 to 7.31), p=0.75
 Azithromycin−2.35 (−8.44 to 3.73), p=0.45−2.29 (−8.43 to 3.86), p=0.47
Adherence to treatment. OR (95% CI)
 Moxifloxacin0.89 (0.05 to 15.09), p=0.940.74 (0.04 to 15.61), p=0.85
 Doxycycline0.64 (0.05 to 9.02), p=0.740.60 (0.04 to 9.68), p=0.72
 Azithromycin1.34 (0.07 to 26.06), p=0.842.42 (0.09 to 63.28), p=0.60
Exacerbation frequency. Relative risk (95% CI)
 Moxifloxacin1.36 (0.62 to 2.97), p=0.441.38 (0.62 to 3.10), p=0.43
 Doxycycline2.05 (0.98 to 4.29), p=0.062.07 (0.99 to 4.35), p=0.05
 Azithromycin0.83 (0.35 to 1.93), p=0.660.72 (0.30 to 1.71), p=0.45
Antibiotic resistance testing
Factor change in MIC
 Moxifloxacin4.82 (1.44 to 16.19), p=0.01
 Doxycycline3.74 (1.46 to 9.58), p=0.01
 Azithromycin6.23 (1.66 to 23.35), p=0.01
 OR for resistant isolates
 Moxifloxacin2.03 (0.36 to 11.54, p=0.42
 Doxycycline5.77 (1.40 to 23.74, p=0·02)
 Azithromycin2.42 (0.61 to 9·62, p=0.21)
Sputum inflammatory markers
IL-1β (log10 pg/mL)
 Moxifloxacin−0.25 (−0.63 to 0.14), p=0.21−0.15 (−0.56 to 0.26), p=0.47
 Doxycycline−0.10 (−0048 to 0.28), p=0.61−0.03 (−0.43 to 0.37), p=0.88
 Azithromycin0.04 (−0.35 to 0.43), p=0.860.09 (−0.31 to 0.49), p=0.66
IL-6 (log10 pg/mL)
 Moxifloxacin−0.16 (−0.50 to 0.18), p=0.37−0.22 (−0.59 to 0.16), p=0.27
 Doxycycline−0.21 (−0.56 to 0.13), p=0.22−0.23 (−0.58 to 0.13), p=0.25
 Azithromycin−0.19 (−0.43 to 0.27), p=0.65−0.06 (−0.42 to 0.30), p=0.77
IL-8 (log10 pg/mL)
 Moxifloxacin−0.26 (−0.72 to 0.19), p=0.26−0.29 (−0.78 to 0.19), p=0.24
 Doxycycline−0.11 (−0.55 to 0.34), p=0.64−0.08 (−0.54 to 0.38), p=0.74
 Azithromycin0.00 (−0.46 to 0.46), p=1.000.02 (−0.45 to 0.49), p=0.94
  • *The results in the right hand column were adjusted for age, sex, smoking status, FEV1% predicted and prior exacerbation history. p Values were calculated using the Wald test.

  • IL, interleukin; MIC, mean inhibitory concentration; qPCR, quantitative PCR; SGRQ, St George's Respiratory Questionnaire.