#1968 IgA nephropathy and impact of proteinuria and kidney function decline on healthcare resource utilisation among adults in the United Kingdom

Abstract

Abstract Background and Aims Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis and can result in kidney failure, especially if left untreated. Proteinuria ≥1.0 g/day is a major risk factor for IgAN progression and rapid kidney function decline. This study describes the characteristics of patients with IgAN in the United Kingdom (UK) and the impact of proteinuria and chronic kidney disease (CKD) stage on healthcare resource utilisation (HRU) and costs. Method In this retrospective, descriptive analysis, eligible patients had at least one code among ICD-9 583.9, ICD-10 N02.8, and ICD-10 N02.9 between 1 October 2015 and 1 October 2022. They were stratified by CKD stage and proteinuria level. CKD stage was defined by ICD-10 N18 code and estimated glomerular filtration rate. Proteinuria level was grouped as low or high by protein excretion rate (<1 g/day vs ≥1 g/day), protein/creatinine ratio (<0.88 g/g vs ≥0.88 g/g), or albumin/creatinine ratio (<100 mg/mmol vs ≥100 mg/mmol). HRU data for 1 year from the index date were obtained from electronic medical records, and costs were obtained from the National Schedule of the National Health Service 2021/22. Weighted average costs were calculated for inpatient, outpatient, and emergency visits. Results We identified 6 940 patients with IgAN. The mean age was 62 years, and most patients (n = 3 980; 57%) were male. For all visit types, HRU (Fig.) and costs (Table) increased with advancing CKD. For all visit types combined, the mean total cost per patient was >23 times higher for CKD stage 5 than stage 1 (£60 259 vs £2 609). Of 2 080 patients with proteinuria data, 560 (27%) had high proteinuria. Annual costs per patient (Table) and the numbers of all visit types (Figure) were higher for patients with a protein excretion rate ≥1 g/day than those with a rate <1 g/day (£12 622 vs £2 822). Conclusion In patients with IgAN in the UK, elevated proteinuria and advanced CKD stage were associated with higher HRU and costs across visit types. Treatments that reduce proteinuria can slow disease progression and prevent rapid decline in kidney function while potentially reducing IgAN-related resource utilisation and costs.