Healthcare of patients with immunoglobulin A nephropathy through a retrospective observational study of Italian administrative data.

Background: Immunoglobulin A nephropathy (IgAN) is a rare disease poorly described in real-world settings. This observational retrospective study aimed to assess the direct healthcare burden of new IgAN patients on the Italian National Healthcare Service (SSN). Methods: From the Fondazione Ricerca e Salute's database (administrative healthcare data of ~5.5 million inhabitants/year), inpatients with new potential in-hospital biopsy-verified IgAN from 2016 to 2019 were identified. Dispensations of IgAN-recommended and other drugs, kidney replacement therapies (KRT), hospital and emergency department (ED) admissions, local outpatient specialist care, and related direct costs were assessed throughout a 3-year follow-up. Results: New IgAN patients (n = 292) were identified (incidence/year: 1.25/100 000 inhabitants); 64% of patients were male; the median age was 41 (27; 57) years. Annual consumption of most healthcare resources decreased from Year 1 to 3: from 90% to 84% of patients received ≥1 IgAN-recommended drug; from 100% (due to selection criteria) to 15% of patients underwent overnight hospitalizations; from 8% to 3% patients underwent day hospitalizations; from 31% to 21% patients underwent ≥1 ED access; from 87% to 85% patients received local outpatient specialist services. Of all patients, 2-4% were treated with KRT, and ~91% received other drugs. The per capita mean total annual cost was €7441 in Year 1 (hospitalizations accounting for 73% due to selection criteria), €3497 in Year 2, and €3243 in Year 3 (drugs accounting for 51%, mostly attributable to other drugs). Conclusion: This real-world study shows a substantial direct healthcare burden for new IgAN patients arising from IgAN-specific care and comorbidities.