Table 1.

Characteristics of studies included for mortality risk evaluation.

Study	Design	Patient	Age (mean)	Man/woman	LTOS/placebo	Steroid duration	Steroid dose	Follow-up duration	Relative risk
Ström8	Prospective cohort	COPD, LTOT	67.0 years	201/202	211/192	>6 months	Prednisolone 7.5 mg/day	6 years	1.38 (1.05–1.82)
Schols et al.9	Retrospective case– control	COPD	65.0 years	415/141	391/165	>6 months	Prednisolone ≥10 mg/day	2 years	3.33 (1.77–6.27)
Groenewegen et al.10	Prospective cohort	COPDa	70.6 years	104/67	17/154	≥1 year	Prednisolone ≥5 mg/day	1 year	3.36 (1.98–5.67)
Ringbaek et al.11	Prospective cohort	COPD, LTOT	69.7 years	104/117	76/145	≥1 year	Prednisolone 5–10 mg/day	4.9 years	1.08 (0.89–1.30)
Horita et al.12	Prospective cohort	COPD, FEV1 < 45%	66.5 years	286/158	102/342	≥6 months	Not available	5 years	1.25 (1.10–1.42)

COPD: chronic obstructive pulmonary disease; FEV₁: forced expiratory volume for one second; LTOT: long-term oxygen therapy; LTOS: long-term oral steroid.

^aAdmitted due to acute exacerbation.