Economic impact of self-administered subcutaneous versus clinic-administered intravenous immunoglobulin G therapy in Alberta, Canada: a population-based cohort study

Background Self-administered subcutaneous immunoglobulin G (SCIg) reduces nursing time and eliminates the need for treatment at ambulatory care clinics, as compared with clinic-based intravenously administered IgG (IVIg), and are therapeutically equivalent. Estimating the economic impact of self-administered SCIg versus clinic-administered IVIg therapy may guide treatment recommendations. Methods A retrospective population-based cohort study using administrative data from Alberta was performed; those treated with IgG between April 1, 2012 and March 31, 2019 were included. Costs for medical laboratory staff and nursing time, as well as ambulatory care visits were considered. Univariate generalized linear model regression with gamma distribution and log link was used to compare cost ($CDN 2020) between SCIg and IVIg administration. Stratified analysis by age (≥ 18-years; < 18-years) was performed. Results Among 7,890 (6,148 adults; 1,742 children) individuals who received IgG, the average administration cost per patient-year of self-administered SCIg was $5,386 (95% confidence interval [CI] $5,039, $5,734) lower than clinic-administered IVIg; per patient-year cost of self-administered SCIg was $817 (95% CI $723, $912) versus $6,204 (95% CI $6,100, $6,308) for clinic-administered IVIg. The per patient-year cost of self-administered SCIg was $5,931 (95% CI $5,543, $6,319) lower among adults and $3,177 (95% CI $2,473, $3,882) lower among children compared with clinic-administered IVIg. An estimated $31.0 million (95% CI $29.0, $33.0) in cost savings to the health system would be realised if 80% of individuals switched from clinic-administered IVIg to self-administered SCIg. Conclusions Self-administered SCIg is substantially less costly from a health care payer perspective in Canada. Within this type of health system, switching to self-administered SCIg has the potential to reduce overall health care costs, lessen nursing burden, and may increase clinic-based capacity for others.