Table 1

The main characteristics of the studies and the relevant data included in the meta-analyses

First author	Year	Country	N	Min age	% Male	Follow-up (avg. months)	ICU LoS (days)	Mortality	Severity (scaled avg.)	Raw measure	Comparison	Quality
Abelha	2007	Portugal	112	65+	61.00%	6		28.00%		SF-36 *	ICU survivors younger than 65 years old	M
Ali	2018	Australia	32	65+	80.00%†	12	5		0.24	EQ-5D	Age-matched South Australian controls	H
Andersen	2015	Norway	53	80+	69.00%	40.8	1.9	81.52%	0.27	EQ-5D	Age-matched and sex-matched Norwegian population	M
De Rooij	2008	Netherlands	187	80+	51.00%	44.4	1.29	61.52%	0.21	EQ-5D	Age-matched British population	M
Eddleston	2000	UK	39	65+	52.45%†	3				SF-36*	ICU survivors younger than 65 years old	M
Ferrao	2015	Portugal	290	66+‡	26.00%	27.6				EQ-5D	ICU survivors younger than 65 years old	M
Grace	2007	Australia/NZ	99	60+	NR	28		60.00%	0.28	EQ-5D	Retrospective patient ratings for 1 week before ICU	L
Hofhuis	2011	Netherlands	49	80+‡	46.90%	6	5.35	40.83%	0.25	SF-36*	Age-matched Dutch population and retrospective proxy ratings for 4 weeks before ICU	M
Honselmann§	2015	Germany	352	65+	53.40%	12	2.58	43.36%		EQ-5D	ICU survivors younger than 65 years old
Honselmann^c-d	2015	Germany	291	65+	53.61%	12	2.34	43.36%		EQ-5D	Age-matched German controls
Jeitziner	2015	Switzerland	124	65+	73.00%	12	4.57		0.29	SF-36*	Age matched Swiss controls and retrospective patient ratings for 1 week before ICU	M
Kaarola	2006	Finland	299	65+	75.00%	47		57.00%		EQ-5D	ICU survivors younger than 65 years old	M
Levinson	2016	Australia	322	80+	58.00%†	24	1.28	21.45%		SF-36*	Age-matched and sex-matched Australian population	H
Merlani	2007	Switzerland	36	70+	52.00%	24	3.00	63.00%	0.26	EQ-5D	Age-matched Swiss population	M
Oeyen	2007	Netherlands	63	80+	60.00%†	12		49.60%	0.26	EQ-5D	Retrospective patient or proxy ratings for 1 week before ICU	M
Sacanella	2011	Spain	112	65+	57.00%	12	3.35	48.70%	0.27	EQ-5D	Retrospective patient or proxy ratings before feeling ill and requiring ICU	M
Schroder	2011	Denmark	36	75+	56.00%	12	9.4	53.85%		SF-36*	Age-matched Danish population	L
Sznajer	2001	France	65	65+‡	55.90%†	6				EQ-5D	ICU survivors younger than 65 years old	M
Villa	2016	Spain	54	75+	50.00%	12		43.18%	0.23	SF-36*	Spanish population aged 75+	M
Weighted avg.			128.53	69.50	55.74%	22.98	3.02	44.92%	0.26
Range			23–352	60–80	26%–80%	3–100.8	1.28–9.4	21.45%–81.52%	0.12–0.34

See above for measures. Unless specified, we do not report data where it is not representative of at least 66.67% of the included sample.
Where the manuscript did not report the relevant information, we marked this as NR.
*Converted to EQ-5D composite score.
†Reported for study level only so not included in meta-analysis.
‡Combined elderly groups.
§We analysed some unpublished data from Honselmann et al; therefore, we have presented descriptions for the full dataset only, without quality assessment.
¶In the Honselmann study, the sample for the community study was slightly smaller than for the young/old comparison.
H, high quality; ICU, intensive care unit; L, low quality; LoS, length of stay; M, moderate quality.