Table 1.

Baseline characteristics of the included studies

Author	Design	Sample	Age (mean/median)	Male (%)	Hypertension (%)	HF (%)	CAD (%)	CLD (%)	Outcome	NOS
Baycan et al. [16]	Retrospective cohort	100	55.6	50	29	-	-	-	Mortality	8
Bursi et al. [17]	Retrospective cohort	49	65.7	63.3	49	6.1	22.4	12.2	Mortality	8
Croft et al. [6]	Retrospective cohort	58	54.1	58.6	68.9	17.2	22.4	13.8	Mortality	6
Janus et al. [7] (letter)	Retrospective cohort	31	64	-	-	-	-	-	Mortality	-
Kim et al. [15]	Prospective–retrospective cohort	40	60	50	37.5	0	0	0.03	Severity	8
Lassen et al. [4]	Prospective cohort	214	68.9	54.7	57	10.3	15.9	15	Mortality	8
Li et al. [8]	Cohort	120	61	48	40	-	9.2	5	Mortality	9

CAD coronary artery disease, CLD chronic lung disease, HF heart failure, NOS Newcastle Ottawa Scale