Table 4.

Secondary outcomes: self-reported versus PSG-recorded sleep behaviours

	Self-report	PSG	Agreement
Sleep-onset position (n=40)*
Left	31 (78%)	29 (73%)	Cohen’s κ† 0.62
Supine	2 (5%)	3 (7%)
Right	7 (17%)	8 (20%)
Waking position (n=40)*
Left	28 (70%)	22 (55%)	Cohen’s κ† 0.42
Supine	0 (0%)	5 (13%)
Right	12 (30%)	13 (32%)
No of position changes (n=30)‡	3 (2–4)	6 (3.3–10)	Cohen’s κ§ 0.17
% of total sleep time in position (n=35)¶:
Left	59.9 (28.1)	54.4 (26.4)	Spearman’s ρ 0.76
Supine	7.8 (20.0)	14.8 (18.7)	Spearman’s ρ 0.27
Right	31.3 (27.3)	30.8 (28.5)	Spearman’s ρ 0.93

*Count data are presented as: frequency (%).

†Linear/equal weighted Cohen’s κ.

‡Ordinal data presented as: median (IQR).

§Unweighted Cohen’s κ.

¶Continuous data presented as: mean (SD).

PSG, polysomnogram.