To Örebro University

This thesis investigates the associations between IgA nephropathy (IgAN), a common form of primary glomerulonephritis, and several health outcomes including inflammatory bowel disease (IBD), cancer, infections, and the reliability of biopsy data from the Swedish Renal Registry (SRR).

In a population-based cohort study of 3,963 IgAN patients and 19,978 controls, IgAN was linked to a significantly higher risk of both future and preceding IBD diagnoses. IBD also increased the risk of developing end-stage renal disease (ESRD) in IgAN patients, underscoring the importance of monitoring gastrointestinal comorbidities in this population.

Another cohort study of 3,882 IgAN patients examined the association between IgAN and cancer. An elevated cancer risk was identified, but only in patients who progressed to ESRD, suggesting that the increased cancer incidence is related to advanced kidney disease rather than IgAN itself.

A third study explored the frequency of infections in IgAN patients, revealing a higher incidence of infections and increased antimicrobial use compared to both the general population and sibling controls. The study highlighted a marked risk of sepsis, emphasizing the need for proactive infection prevention in IgAN management.

Finally, validation of biopsy data from the SRR demonstrated a high positive predictive value (95%) for IgAN diagnosis. This reinforces the reliability of the SRR as a valuable tool for future research on IgAN.

Together, these findings contribute to a deeper understanding of IgAN’s broader clinical implications, and the potential risks associated with its progression.