Table 2.

Outputs of the interrupted time series. “Annual visits” indicates slope; “period” indicates the pre- or postindex period.

Variable	Medical doctor visits			Nurse practitioner or physician assistant visits			Triage calls
	Estimate	P value	Estimate		P value	Estimate		P value
Intercepta	1.572	<.001	0.618		<.001	0.335		<.001
Annual visits (slope)b	0.009	.19	0.049		<.001	0.045		<.001
Period (before or after index)c	0.002	.97	-0.011		.77	0.062		.02
Annual visits × periodd	0.036	.002	-0.042		<.001	0.010		.05
Portale	0.008	.86	-0.018		.59	–0.033		.10
Portal × annual visitsf	0.014	.15	-0.010		.12	–0.005		.26
Portal × periodg	0.417	<.001	0.069		.21	0.102		.006
Portal × annual visits × periodh	–0.054	.001	0.028		.01	–0.005		.46

^aControl arm intercept.

^bPre–index date slope of annual visits for the control arm.

^cChange in number of visits in year 2 post–index date relative to that anticipated from preindex slope for the control arm.

^dChange in the slope of annual visits in the postindex period relative to the preindex period for the control arm.

^eDifference between the portal arm and control arm in the intercept.

^fDifference between the portal arm and control arm in the pre–index date slope of annual visits.

^gDifference between the portal arm and control arm in the change in number of visits in year 2 post–index date relative to that anticipated from preindex slope.

^hDifference between the portal arm and control arm in the change of the slope of annual visits in the postindex period relative to the preindex period.