Pregnant IgAN Patients with Adverse Outcomes Less Likely to Reach Proteinuria Remission

Credit: Adobe Stock/ Gregory Miller

Pregnant patients with IgA nephropathy (IgAN) who are at risk for adverse pregnancy outcomes were less likely to reach proteinuria remission than IgAN patients without a risk for adverse pregnancy outcomes, a new study found.¹

“Our study suggests that APO could pose an adverse effect on proteinuria remission of pregnant IgAN patients but not affect the renal function progression in pregnant IgAN patients,” wrote investigators, led by Fengxia Zhang, from the department of nephrology at First Affiliated Hospital of Gannan Medical University in China.

According to the American Kidney Fund, 8 out of 10 people with IgA nephropathy are diagnosed between ages 16 – 35 years, and thus many people with this disease are childbearing age.² Not only that, but pregnant patients with IgAN are more susceptible to adverse pregnancy outcomes.¹ Even though patients with IgAN are at greater risk, it was not clear what impact the risk for adverse pregnancy outcomes would have on long-term renal outcomes among this population.

Investigators conducted a retrospective observational study to identify risk factors for adverse pregnancy outcomes and their impact on clinical IgAN outcomes. The team evaluated for renal function outcome and proteinuria remission in pregnant IgAN women with and without adverse pregnancy outcomes. Adverse pregnancy outcomes were defined as 1 of the following: gestational hypertension, abortion, preterm delivery (<37th gestational week), and gestational diabetes.

The study included 44 patients with IgAN from Guangdong Provincial People’s Hospital from January 2003 to December 2019. Participants had to be female with a history of pregnancy, ≥ 18 years and ≤ 40 years, followed up ≥ 6 months, and had normal renal function before pregnancy. Among the 44 patients, the number with and without adverse pregnancy outcomes was 24 and 20, respectively.

Investigators collected baseline clinical and pathological data from electronic records:

Clinical data: Age, systolic blood pressure, diastolic blood pressure, erythrocyte phase, serum creatinine, estimated glomerular filtration rate, 24-hour proteinuria, 24-hour albuminuria, serum albumin, hemoglobin, platelet, blood uric acid, cholinesterase, cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, alanine aminotransferase, aspartate aminotransferase, serum IgG, IgA, IgM, complement C3 and complement C4.

Pathological parameters: Mesangial hypercellularity, endocapillary cellularity, segmental sclerosis, interstitial fibrosis/tubular atrophy, crescents, and immunohistological staining including IgG, IgA, IgM, C3, and C1q deposition.

The study found patients with adverse pregnancy outcomes had greater levels of serum creatinine and IgM, as well as lower hemoglobin levels, compared with patients without adverse pregnancy outcomes. Clinical characteristics, pathological characteristics, and therapy protocol had no significant difference between groups.

The univariate model showed patients had an increased risk of adverse pregnancy outcomes with lower levels of eGFR, serum albumin, hemoglobin and a higher level of serum creatinine and IgM (P < .1). After adjusting for several confounders, the multivariate logistic analysis identified lower levels of hemoglobin (odds ratio [OR], 0.915; 95% confidence interval [CI], 0.838 to 0.999; P = .048) and greater levels of IgM (3.328; 95% CI, 1.055 to 10.496; P = .040) as independent risk factors for adverse pregnancy outcomes.

Ultimately, women with adverse pregnancy outcomes were more likely to reach proteinuria remission, defined as 24-hour proteinuria below 0.3 g once during the follow-up (P = .0026). Women with and without adverse pregnancy outcomes had no difference in renal function outcome (P = .8316). An adjusted analysis found adverse pregnancy outcomes among pregnant women with IgAN were an independent risk factor for not achieving proteinuria remission.

“Pregnant IgAN patients with higher risks, including lower hemoglobin levels and higher IgM levels deserve intensive monitoring, and aggressive therapy to reduce proteinuria should be carried out in pregnant IgAN patients with [adverse pregnancy outcomes],” investigators concluded.

References

1. ^{Zhang F, Xie Z, Peng S, et al. The risk factor for adverse pregnancy outcomes and its impact on clinical effect in IgA nephropathy: A retrospective observational study. Nephrology (Carlton). Published online September 10, 2024. doi:10.1111/nep.14387}
2. ^{American Kidney Fund. IgA Nephropathy. August 19, 2024. https://www.kidneyfund.org/all-about-kidneys/other-kidney-diseases/iga-nephropathy. Accessed September 20, 2024.}