Introduction:
IgA nephropathy (IgAN) is the leading cause of glomerulonephritis and renal failure. Globally, variation in the epidemiology and clinical presentation have been noted. In China, evidence quantifying the incidence and prevalence of IgAN is limited. Proteinuria (>1g/day) is a risk factor for disease progression in patients with IgAN. However, evidence related to occurrence of proteinuria among Chinese IgAN patients is insufficient. This study aimed to summarize findings from literature on incidence and prevalence of IgAN in patients with renal biopsies, as well as the proportion of patients with elevated proteinuria levels in real-world clinical settings in China.
Methods:
We systematically reviewed observational studies published between 2008/01/01 and 2024/02/19 in MEDLINE, Embase and China National Knowledge Infrastructure for incidence and prevalence of IgAN in Chinese population. Studies published since 2020/01/01 were also reviewed to identify patients with elevated proteinuria levels (total protein >1g/day). Meta-analysis was performed using a random-effects model to estimate the incidence and prevalence proportions of IgAN among patients who underwent renal biopsy, and the proportion of patients with elevated proteinuria levels.
Results:
The meta-analysis included 83 studies for incidence and prevalence estimates. Incidence estimates were described as proportions of patients diagnosed with IgAN. Meta-analysis found that among pediatric and adult patients with renal biopsies, IgAN incidence proportion was 33% (95% CI: 28–39%) in 2000–2009 and 28% (95% CI: 24–32%) in 2010–2022, with no statistically significant difference over time; the corresponding prevalence proportion was 33% (95% CI: 27–40%) and 25% (95% CI: 22–29%), with a significantly decreasing time trend (p=0.03). To estimate elevated proteinuria levels among all biopsy confirmed IgAN patients, a meta-analysis of six studies published since 2020 was conducted. The pooled proportion of adult and pediatric IgAN patients with elevated proteinuria levels was 41% (95% CI: 23–59%).
Conclusions:
The incidence proportion of IgAN was nearly 30% among all patients with renal biopsies. This relatively high incidence reflected the improvement in pathological testing in Chinese hospitals, enabling timely diagnosis of IgAN. Person-time based incidence rate could not be estimated due to data availability limitations. Evidence on the person-time-based incidence rate of IgAN is needed to better understand how quickly IgAN occurs in the Chinese population, which may inform optimization of prevention, diagnosis, and treatment strategies for IgAN. To our knowledge, this is also the first meta-analysis to report proportion of elevated proteinuria levels (total protein >1g/day) among Chinese patients with IgAN, which was reported to be 41%.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.