Table 4.

Linear regression model of determinates of the total number of emergency department attendances between July 2018 and July 2023 amongst individuals with antibody deficiency in the Birmingham cohort

Variable	Estimate	Standard error	95% CI (asymptotic)	P value
Age	0.00692	0.00567	-0.00424 to 0.0181	0.2233
Sex	0.347	0.177	-0.000911 to 0.695	0.0506
Secondary antibody deficiency	0.710	0.198	0.319 to 1.10	0.0004
Treatment with IVIG	0.787	0.232	0.330 to 1.25	0.0008
Treatment with SCIG	0.366	0.214	-0.0563 to 0.788	0.0891

Linear regression model uses sex and primary vs. secondary antibody deficiency as binary categorical variables (male sex and secondary antibody deficiency as reference levels), and immunological treatment as a three-level categorical variable with treatment with prophylactic antibiotics as a reference level