Table 5.

Correlation of IgG, IgM and IgA levels with clinical outcomes

Clinical Outcomes	IgG			IgM			IgA
	All (N = 51)	Low IgG (N = 14)	Normal IgG (N = 35)	All (N = 51)	Low IgM (N = 16)	Normal IgM (N = 34)	All (N = 51)
Length of hospital stay	R = 0.275 p = 0.051	R = − 0.439 p = 0.116	R = 0.262 p = 0.128	R = − 0.317 p = 0.024	R = 0.249 p = 0.353	R = 0.046 p = 0.798	R = 0.198 p = 0.163
Emergency department visits	R = − 0.052 p = 0.717	R = − 0.267 p = 0.357	R = 0.095 p = 0.586	R = − 0.110 p = 0.441	R = 0.012 p = 0.965	R = − 0.260 p = 0.138	R = − 0.232 p = 0.102
Readmissions	R = − 0.005 p = 0.973	R = − 0.469 p = 0.090	R = 0.174 p = 0.318	R = 0.014 p = 0.920	R = 0.086 p = 0.752	R = − 0.042 p = 0.812	R = − 0.070 p = 0.624
AECOPD related hospital readmissions	R = − 0.104 p = 0.467	R = − 0.527 p = 0.053	R = − 0.019 p = 0.914	R = − 0.033 p = 0.816	R = 0.250 p = 0.351	R = − 0.073 p = 0.680	R = − 0.116 p = 0.419

Bold value denotes statistical significance at the p < 0.05 level

AECOPD Acute chronic obstructive pulmonary disease exacerbation, R Correlation coefficient

N = 2, IgG > 16.18 g/L or higher than normal range

N = 1, IgM > 3.0, or higher than normal range