Table 2.

Definition of terms

Term	Definition
Naïve	A patient who did not have a treatment of interest at a given time point but had a claim with a psoriasis diagnosis (ICD-9 code 696.1) at some point during the analysis window
Days of service	Length of period of treatment or procedure awarded by the prescription (31 days if not recorded or <31 days). Procedures were assigned 31 or 61 days of service
Grace period	Additional 61 days added to days of service to account for poor compliance/adherence/concordance and to prevent very short switches out of and back into treatment
Lapsed	A patient who received a treatment of interest during the analysis window but was not on a treatment of interest at a given time point beyond the grace period
Lapsed biologic/systemic-experienced	Patients who had previously received a traditional biologic or systemic treatment but were only receiving topical treatment at a given time point beyond the grace period
Compliance	Adherence to treatment plan during the analysis window
Switch	Change in treatment status (i.e., starting, re-starting, or changing treatment)
Untreated	Not treated in the 5-year window with any of the drugs of interest

ICD-9 International Classification of Diseases, Ninth Revision