Subgroup estimates of the effectiveness of antibiotics for the duration of symptoms rated moderately bad or worse, using the combined observational and trial datasets
| Subgroup | Number | No antibiotics, median (IQR) | Antibiotics, median (IQR) | Interaction term HR (99% CI)a | Unadjusted HR (99% CI) | Adjusted HRb (99% CI)a |
|---|---|---|---|---|---|---|
| Abnormal chest signs | 1.02 (0.68 to 1.52) | |||||
| Yes | 314 | 5 (4–14) | 5 (3–8) | 1.10 (0.80 to 1.51) | 1.06 (0.77 to 1.46) | |
| No | 430 | 7 (5–12) | 5 (3–10) | 1.23 (0.95 to 1.58) | 1.19 (0.94 to 1.52) | |
| Sputum | 1.46 (0.91 to 2.34) | |||||
| Yes | 568 | 7 (4–14) | 5 (3–9) | 1.34 (1.07 to 1.67) | 1.29 (1.03 to 1.61) | |
| No | 171 | 5 (3–10) | 5 (3–9) | 0.85 (0.54 to 1.34) | 0.86 (0.54 to 1.38) | |
| Fever | 1.49 (0.90 to 2.44) | |||||
| Yes | 579 | 6 (4–13) | 5 (3–8) | 1.32 (1.00 to 1.77) | 1.28 (1.03 to 1.60) | |
| No | 165 | 6 (4–12) | 6 (3–23) | 0.87 (0.55 to 1.39) | 0.72 (0.44 to 1.18) | |
| Physician rating of unwell | 1.24 (0.82 to 1.86) | |||||
| Yes | 488 | 6 (4–11) | 5 (3–8) | 1.32 (1.03 to 1.71) | 1.26 (0.98 to 1.63) | |
| No | 254 | 7 (4–14) | 5 (3–14) | 1.04 (0.74 to 1.45) | 1.03 (0.74 to 1.47) | |
| Shortness of breath | 0.97 (0.66 to 1.42) | |||||
| Yes | 365 | 6 (4–11) | 5 (3–9) | 1.29 (0.97 to 1.71) | 1.26 (0.94 to 1.68) | |
| No | 379 | 6 (4–14) | 5 (4–10) | 1.21 (0.91 to 1.59) | 1.20 (0.90 to 1.59) | |
| Oxygen saturation <95% | 1.03 (0.51 to 2.10) | |||||
| Yes | 57 | 6 (4.5–14.5) | 6 (3–10) | 0.96 (0.33 to 2.75) | 1.20 (0.24 to 5.93) | |
| No | 516 | 6 (4–13) | 5 (3–9) | 1.20 (0.89 to 1.62) | 1.16 (0.94 to 1.43) | |
| STARWAVec | ||||||
| Very low risk | 387 | 6 (4–13.5) | 5 (3–9) | Reference | 1.26 (0.96 to 1.65) | 1.21 (0.92 to 1.59) |
| Normal risk | 326 | 6 (4–11) | 5 (3–8) | 1.03 (0.70 to 1.52) | 1.26 (0.93 to 1.72) | 1.20 (0.88 to 1.64) |
| High risk | 31 | 5 (3–20) | 6.5 (4–11) | — | — | — |
↵a 95% CIs for abnormal chest sign subgroup; 99% CIs for all other subgroups (99% CIs were used as these are secondary analyses).
↵b Adjusted for propensity score.
↵c STARWAVe prediction rule for hospital admission (Short illness, Temperature, Age, Recession, Wheeze, Asthma, Vomiting). CI = confidence interval. HR = hazard ratio. IQR = interquartile range.