Table 2.

Symptom severity^a (standard deviation) in patients consulting in primary care with LRTI treated with amoxicillin versus placebo

	Amoxicillin	Placebo	Interaction termb (95% CI)	p-Value	Difference for subgroupb (95% CI)	p-Value
Whole cohort (n = 1793)	1.59 (0.95)	1.70 (1.01)			−0.07 (−0.15 to 0.01)	0.065
Confirmed infection (n = 1158)	1.71 (0.99)	1.82 (1.02)	0.03 (−0.13 to 0.19)	0.720	−0.06 (−0.16 to 0.04)	0.221
Bacterial infection (n = 390)	1.56 (0.95)	1.87 (1.05)	−0.09 (−0.28 to 0.10)	0.330	−0.14 (−0.31 to 0.03)	0.108
Purely bacterial infection (n = 207)	1.44 (0.95)	1.90 (1.09)	−0.25 (−0.49 to 0.00)	0.048	−0.26 (−0.48 to −0.03)	0.027
Viral infection (n = 880)	1.78 (1.00)	1.83 (1.01)	0.12 (−0.03 to 0.28)	0.119	−0.02 (−0.13 to 0.10)	0.801
Purely viral infection (n = 697)	1.80 (1.01)	1.83 (1.01)	0.09 (−0.07 to 0.25)	0.251	−0.02 (−0.15 to 0.11)	0.755
Combined infection (n = 183)	1.69 (0.94)	1.84 (1.00)	0.10 (−0.15 to 0.36)	0.423	−0.01 (−0.27 to 0.25)	0.943
High PCT (n = 434)	1.67 (0.98)	1.87 (1.14)	−0.09 (−0.27 to 0.09)	0.326	−0.13 (−0.30 to 0.04)	0.144
High BUN (n = 439)	1.45 (0.93)	1.52 (0.98)	−0.03 (−0.21 to 0.16)	0.782	−0.08 (−0.23 to 0.07)	0.294
High CRP (n = 420)	1.88 (1.00)	2.03 (1.03)	−0.07 (−0.25 to 0.12)	0.473	−0.12 (−0.29 to 0.06)	0.201

BUN, blood urea nitrogen; CRP, C-reactive protein; LRTI, lower respiratory tract infection; PCT, procalcitonin.

^aCalculated as the mean (standard deviation) diary score for all symptoms on days 2–4 (rated by the patient).

^bEstimates controlled for baseline symptom severity; negative values favour amoxicillin.