COVID-19’s Impact on Biopsy Rates, IgAN Diagnoses Within the European Union

Immunoglobulin A nephropathy (IgAN), although the most common type of primary glomerulonephritis, is a rare disease within the European Union (EU), according to study findings published in Clinical Kidney Journal.

Furthermore, the study showed that there was a temporary decrease in kidney biopsy rates in some countries during the COVID-19 pandemic, which could result in delayed IgAN diagnoses.

A team of researchers led by Jocelyn Buisker, an epidemiologist at Novartis in Basel, Switzerland, estimated the prevalence of primary IgAN within the EU by conducting four comprehensive literature searches. The researchers evaluated IgAN prevalence and incidence and native kidney biopsy rates, as well as COVID-19’s effect on the metrics.

“The year 2020 marked the beginning of the COVID-19 pandemic in Europe which had large impacts on healthcare across the continent,” the researchers said.

Country-specific IgAN prevalence estimates were collected from across 27 EU countries and calculated based on a combination of published and modeled data, which included biopsy frequency and the Healthcare Access and Quality Index (HAQI). In addition, IgAN prevalence was derived from country-specific prevalence estimates weighted by population size.

The researchers observed an estimated prevalence of IgAN in the EU as 4.31 per 10,000 population based on data from 18 EU countries and calculated data for nine countries. Country-specific estimates ranged from 0.16 in Romania to 14.4 per 10,000 in Finland.

Moreover, a strong correlation was seen between IgAN incidence and biopsy rates. The researchers found that countries with a higher HAQI had a higher biopsy rate compared with countries with a lower HAQI. Particularly, countries in the eastern parts of Europe demonstrated a lower HAQI versus countries in the western parts.

Investigation into COVID-19’s effect on kidney biopsy rates revealed a significant decrease for most European countries in 2020 compared with pre- and post-pandemic periods. Patients with less severe symptoms, those who were younger, and women were most affected by the decreased biopsy rate. The decrease was attributed to several potential factors, including the switch of nephrology departments to urgent care with fewer biopsies performed, patients avoiding hospital visits, limited access to primary care, and a reduction in referrals to secondary care during the pandemic.

“While most of the published evidence pointed towards a decreased biopsy rate across Europe during the COVID-19 pandemic, it is unclear whether it had long-lasting effects on the kidney biopsy rate or IgAN incidence that would affect today’s IgAN prevalence,” the researchers said.

Source: Buisker J, et al. Clin Kidney J. 2025;18(4):sfaf068. doi:10.1093/ckj/sfaf068