Table 3.

CYP2C19 genotype, lansoprazole treatment, and gastroesophageal reflux symptoms^*

	Placebo		Lansoprazole				P Values for Pairwise Comparisons†
	n	All	n	EM	n	PM	Plb vs. EM	Plb vs. PM	EM vs. PM
GSAS score‡
Baseline	141	20	94	20	43	18	0.64	0.95	0.68
∆3 mo		–6		–7		3	0.76	0.95	0.68
∆6 mo		–8		–6		–4	0.71	0.38	0.60
Number of daily symptoms
Baseline	141	3	94	3	43	3	0.64	0.43	0.90
∆3 mo		–1		–1		−1	0.97	0.89	0.90
∆6 mo		–1		–1		–1	0.09	0.52	0.60

Definition of abbreviations: EM = extensive metabolizer; GSAS = GERD (gastroesophageal reflux disease) Symptom Assessment Score; Plb = placebo; PM = poor metabolizer.

^*P values for treatment effects (lansoprazole vs. placebo) from general estimating equation models including treatment status, all measurement time points, interactions with treatment status at each time point, sex, and black race. Estimates not included in table.

^†P values and model estimates for pairwise comparisons of placebo (all), extensive metabolizers assigned to lansoprazole, and poor metabolizers assigned to lansoprazole from general estimating equation models including lansoprazole exposure status (placebo or EM or PM), all time points, and interactions with lansoprazole exposure at each time point, sex, and black race.

^‡Scores range from 0 to 441, with higher values suggesting worse symptoms.