Adjunct prednisone in community-acquired pneumonia: 180-day outcome of a multicentre, double-blind, randomized, placebo-controlled trial

Table 3 Subgroup analyses for the primary endpoint mortality

Subgroup variables	Placebo (n = 366)	Prednisone (n = 361)	Cox regression, HR (95%CI)	p for heterogeneity (interaction)^b
Median age				0.326
Age ≤ 73 years	8/192 (4.2%)	6/177 (3.4%)	0.97 (0.33–2.90)
Age > 73 years	17/174 (9.8%)	29/184 (15.8%)	1.36 (0.74–2.51)
Initial median CRP				0.801
CRP ≤ 158 mg/L	14/181 (7.7%)	19/180 (10.6%)	1.37 (0.67–2.78)
CRP > 158 mg/L	11/182 (6.0%)	15/179 (8.4%)	1.10 (0.49–2.46)
History of Chronic Obstructive Pulmonary Disease				0.989
no	21/312 (6.7%)	25/291 (8.6%)	1.26 (0.70–2.27)
yes	4/54 (7%)	10/70 (14%)	1.51 (0.45–5.12)
Pneumonia severity index^a				0.632
PSI class I-III	4/193 (2.1%)	6/174 (3.4%)	1.77 (0.50–6.29)
PSI class IV-V	21/173 (12.1%)	29/187 (15.5%)	1.14 (0.65–2.03)
Blood culture positivity				0.505
Blood culture negative	22/321 (6.9%)	30/324 (9.3%)	1.12 (0.64–1.97)
Blood culture positive	3/45 (7%)	5/37 (14%)	1.17 (0.24–5.64)
Sex				0.445
Male	7/135 (5.2%)	16/142 (11.3%)	1.85 (0.75–4.60)
Female	18/231 (7.8%)	19/219 (8.7%)	0.96 (0.49–1.88)
Microbiological etiology
Bacterial proof				0.429
Yes	5/87 (6%)	10/81 (12%)	1.83 (0.58–5.74)
No	17/245 (6.9%)	22/254 (8.7%)	1.05 (0.55–2.02)
Viral proof				0.364
Yes	1/38 (3%)	3/38 (8%)	0.44 (0.22–9.01)	0.364
No	16/181 (8.8%)	18/176 (10.2%)	1.05 (0.52–2.11)

Data are number (%) unless otherwise stated. HR hazard ratio. CI confidence interval.
^aThe PSI is a clinical prediction rule to calculate the probability of morbidity and mortality in patients with community-acquired pneumonia; PSI risk class I corresponds to age ≤ 50 years, and no risk factors (≤50 points), risk class II to < 70 points, risk class III to 71–90 points, risk class IV to 91–130 points, and risk class V to > 130 points [20].
^bCox proportional hazards model including an interaction term of the respective subgroup variable with treatment group

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