Relations between daytime pulmonary function tests and nocturnal oxygen saturation (S_a,O₂) in neuromuscular disease.

First author [ref. no.]	Disorder	Subjects n	Daytime function correlation with nocturnal S_a,O₂ (r)
			P_a,CO₂	VC	ΔVC	P_{I max}	P_{E max}	Lung volumes
David 2	ALS	17		ns		ns^¶
Gay 4	ALS	21	−0.66	ns^¶		ns^¶	ns^¶
Smith 9	DMD	14	ns	ns	ns	ns	p<0.05⁺	ns
Hukins 10	DMD	19	0.71	−0.46		ns	ns	ns
Manni 39	DMD	11	ns	ns	ns	ns	ns	FRC 0.68 RV 0.67
Finnimore 11	MD	12	ns	ns	ns	ns	ns	ns
White 33	Various	8		ns	−0.78	ns	ns	ns
Labanoswki 34	Various	60	ns^#	0.35	ns	ns	ns
Bye 37	Various	20	0.59	0.79	0.59	ns	ns	ns

ALS: amyotrophic lateral sclerosis
DMD: Duchenne muscular dystrophy
MD: myotonic dystrophy
ΔVC: % fall in vital capacity on lying supine
P_a,CO₂: carbon dioxide tension in arterial blood
P_{I max}: maximal inspiratory pressure
P_{E max}: maximal expiratory pressure
ns: nonsignificant
Studies used different indices of nocturnal desaturation, which influenced the direction of the correlation (e.g. mean S_a,O₂ versus time, S_a,O₂<90%). No study applied a correction for multiple comparisons. Values with p<0.05 are shown
^#: Correlation with awake S_a,O₂=0.78
^¶: Poor or nonsignificant
⁺: Desaturators versus nondesaturators, t‐test