Table 2.

Tobit regression model exponentiated estimates—dependent variable natural log 6-month NOAEL

	Estimate (95% CI)	p value
Oral immunotherapy	105·5 (67·73–164·40)	<0·001
Log (baseline NOAEL + 1)	1·40 (1·15–1·69)	<0·001
Age	0·76 (0·65–0·89)	<0·001
Female	1·42 (0·87–2·31)	0·16
Weight	1·04 (1·01–1·06)	0·004
Quality of life	1·12 (0·89–1·42)	0·32
Asthma	1·09 (0·65–1·74)	0·79
Eczema	0·82 (0·53–1·26)	0·36
Rhinitis	0·69 (0·46–1·05)	0·09
Other food allergy	0·84 (0·52–1·36)	0·48
Family history of peanut allergy	0·41 (0·24–0·71)	0·001
WAO grade 2	2·88 (1·65–5·01)	<0·001
WAO grade 3	0·86 (0·44–1·68)	0·66
WAO grade 4	0·62 (0·21–1·82)	0·40
Peanut SPT wheal diameter	1·02 (0·94–1·11)	0·60
Other nut SPT wheal diameter >3 mm	1·37 (0·81–2·31)	0·23
Tryptase	1·06 (0·95–1·19)	0·32
Log (peanut specific IgE + 1)	0·60 (0·51–0·71)	<0·001
Log (total IgE + 1)	1·74 (1·35–2·23)	<0·001
Log (basophil activation CD63 MFI AUC)	0·98 (0·73–1·32)	0·91

NOAEL is the highest amount of peanut protein (mg) tolerated after OIT. The continuous variables can be interpreted as the percentage change in NOAEL expected from a unit increase of that variable when all other covariates are fixed. The categorical variable estimates can be interpreted as the percentage change compared with the reference group when all other covariates are fixed. For logged covariates the expected percentage change in 6 month NOAEL with a 10% increase in the logged covariate can be calculated as 1·10⁁log (exponentiated estimate). For example, for a 10% increase in baseline NOAEL (mg) we would expect a [1·1⁁log(1·40)=1·032] 3·2% increase in 6 month NOAEL (mg). Similarly, for a 10% increase in baseline peanut specific IgE (kU/L) we would expect a 4·8% decrease in 6 month NOAEL (mg). NOAEL=no observed adverse effect level. OIT=oral immunotherapy. WAO=World Allergy Organization. SPT=skin prick test. MFI=mean fluorescent intensity. AUC=area under the curve.