Table 1.

Changes in Buprenorphine Fill Patterns, January to October 2019 and 2020

	Patients filling buprenorphine prescriptions (95% CI)	P value	Buprenorphine-naïve patients (95% CI)	P value	Mean days’ supply (95% CI)	P value	Patients with active buprenorphine prescriptions (95% CI)	P value
Change at transition
2019	267.7 (53.6, 481.7)	0.02	103.3 (64.5, 142.1)	<0.001	0.16 (−0.01, 0.34)	0.07	284.7 (109.3, 460.1)	0.002
2020	−838.1 (−1133.0, −543.2)	<0.001	−193.5 (−224.6, −162.5)	<0.001	0.81 (0.61, 1.01)	<0.001	118.1 (−214.6, 450.7)	0.48
Difference	−1105.8 (−1470.2, −741.4)	<0.001	−296.8 (−346.5, −247.1)	<0.001	0.65 (0.38, 0.92)	<0.001	−166.7 (−542.7, 209.4)	0.38
Post-intervention weekly growth rate
2019	29.5 (22.4, 36.6)	<0.001	−0.4 (−1.4, 0.6)	0.40	0.018 (0.012, 0.023)	<0.001	123.6 (113.6, 133.6)	<0.001
2020	23.2 (18.9, 27.4)	<0.001	6.2 (5.4, 7.0)	<0.001	−0.008 (−0.010, −0.006)	<0.001	71.6 (55.9, 87.3)	<0.001
Difference	−6.3 (−14.6, 1.9)	0.13	6.6 (5.4, 7.9)	<0.001	−0.026 (−0.032, −0.020)	<0.001	−52.0 (−70.6, −33.4)	<0.001

The change at transition in 2019 and 2020 represents the immediate change at week 12 in the regression model (e.g., change in the weekly number of patients filling prescriptions for buprenorphine). The difference in the change at transition is the difference between the 2019 and 2020 changes. The post-intervention weekly growth rates in 2019 and 2020 are determined from regression coefficients for the treatment (2020) and control (2019) groups in the post-intervention linear time trends from the comparative interrupted time series analysis. The difference in post-intervention weekly growth rates is the difference between the 2019 and 2020 coefficients