Findings refute previous smaller studies
• Many patients with a common kidney disease called IgA nephropathy who had normal kidney function and only minor urinary abnormalities at the time of diagnosis experienced remission without special treatments.
• None developed kidney failure over a 20-year follow-up.
• The findings indicate that patients have an excellent prognosis and can avoid taking potentially toxic immunosuppressive medications.
Prognosis has been difficult to accurately predict in individual patients with IgA nephropathy.
Newswise — Washington, DC (September 6, 2012) — For patients with a common kidney disease who have normal kidney function and only minor urinary abnormalities at the time of diagnosis, the long-term prognosis is excellent and no special treatments are needed, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). The findings contrast with earlier, smaller studies and suggest that patients can avoid taking potentially toxic immunosuppressive medications often used to treat the disease.
IgA nephropathy occurs when antibodies build up in the kidneys, which can cause the kidneys to leak blood and proteins into the urine and in some cases can lead to kidney failure. But some patients with IgA nephropathy have normal kidney function and only minor urinary abnormalities at the time of diagnosis. The long-term prognosis of these patients is unclear.
To investigate, Eduardo Gutiérrez, MD, Manuel Praga, MD, PhD (Hospital Universitario 12 de Octubre, in Madrid), and their colleagues studied 141 Caucasian patients with biopsy-proven IgA nephropathy who had normal kidney function, little or no urinary protein leakage, or proteinuria, and who were not taking immunosuppressive medications for their disease.
Among the major findings:
• After 10, 15, and 20 years, 96.7%, 91.9%, and 91.9% of patients maintained blood creatinine levels under a 50% increase from the start, respectively. (Rising creatinine levels indicate declining kidney function.) No patients developed kidney failure.
• Clinical remission occurred in 53 (37.5%) patients after an average of four years.
• 41 (29.1%) patients had no proteinuria.
• At the start of the study, 23 (16.3%) patients had high blood pressure compared with 30 (21.3%) patients at the end of follow-up.
• 59 (41.8%) patients were treated with medications that lower high blood pressure and proteinuria.
“We demonstrate that the long-term prognosis of this type of patient is excellent and that no special treatments other than those needed to lower blood pressure or treat increasing proteinuria are indicated,” said Dr. Gutiérrez. “Our reassuring data are important because some previous studies had suggested that IgA nephropathy is a progressive disease even in this type of patient with benign presentation,” he added.
Study co-authors include the following investigators in Spain: Isabel Zamora, MD, PhD, José Antonio Ballarín, MD, PhD, Yolanda Arce, MD, Sara Jiménez, MD, Carlos Quereda, MD, PhD, Teresa Olea, MD, Jorge Martínez-Ara, MD, PhD, Alfons Segarra, MD, PhD, Carmen Bernis, MD, PhD, Asunción García, MD, PhD, Marian Goicoechea, MD, PhD, Soledad García de Vinuesa, MD, PhD, and Jorge Rojas-Rivera, MD.
Disclosures: The authors reported no financial disclosures.
The article, entitled “Long-Term Outcomes of IgA Nephropathy Presenting with Minimal or No Proteinuria will appear online at http://jasn.asnjournals.org/ on September 6, 2012, doi: 10.1681/ASN.2012010063.
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