Ten-Year Epidemiology, Economic Burden and All-Cause Mortality Among Generalized Pustular Psoriasis Patients: A Canadian Prevalence Study of Inpatient Care, Emergency Departments, and Hospital- or Community-Based Outpatient Clinics

OBJECTIVES: To document the epidemiology, economic burden and all-cause mortality among generalized pustular psoriasis (GPP) patients seen in Canadian hospitals, emergency departments (ED) and hospital-/community-based outpatient clinics, and to compare with plaque psoriasis (PP).

METHODS:

Data from the Canadian Institute for Health Information were used to identify adult Canadians (excluding Quebec) hospitalized or visiting an ED or hospital-/community-based outpatient clinic between April 1, 2010 and March 31, 2020 with a diagnostic code indicating GPP (i.e., ICD-10-CA L40.1) or PP (ICD10-CA L40.9 or L40.0). Patient characteristics and 10-year costs associated with hospitalizations and visits to an ED or hospital-/community-based outpatient clinic for which the most responsible diagnosis (MRD) was GPP or PP (i.e., “MRD costs”) were documented as was inpatient all-cause mortality. Multivariable generalized linear models (gamma distribution; log link) and logistic regressions were respectively used for comparing costs and all-cause inpatient mortality between GPP and PP when adjusting for patient characteristics. Sensitivity analyses were conducted considering costs associated with any healthcare resource use independent of the presence of a GPP/PP code (i.e., “all-cause costs”).

RESULTS:

Over the 10-year period, 607 (10-year prevalence rate: 2.8/1,000,000) and 24,828 (10-year prevalence rate: 113.1/1,000,000) unique individuals were identified with a GPP or PP code, respectively. The mean age (standard deviation) of our population was 53.1 (17.0) years for GPP and 53.3 (18.3) years for PP (p=0.75), with more GPP patients being female (54.5% versus 44.1%; p<0.01). When compared with PP patients, GPP patients incurred higher 10-year MRD mean (SD) costs ($2,393 [$11,410] versus $132 [$833]; p <0.01) and higher all-cause inpatient mortality (9.2% versus 7.3%; p=0.02). Ten-year all-cause mean (SD) costs were $49,695 ($111,582) for GPP and $42,574 ($83,960) for PP (p<0.01).

CONCLUSIONS:: Findings indicated that the economic burden of GPP is significant as GPP patients incurred higher resource costs and mortality than PP patients.