Corticosteroids rapidly improve kidney function in renal sarcoidosis: Study
Later relapses are frequent, requiring additional immunosuppressive therapies
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Corticosteroid treatment leads to rapid improvements in kidney function in people with renal sarcoidosis, but later relapses are frequent, requiring additional immunosuppressive therapies, according to a Dutch study.
“Our findings support a treatment protocol starting with prednisone [a corticosteroid] … followed by gradual tapering, and the addition of [corticosteroid-sparing] agents in case of relapse” in this patient population, researchers wrote.
They noted, however, that future studies, following patients over time, “are needed to optimize treatment strategies and identify predictive markers for relapse and response.”
The study, “A retrospective multicenter cohort study of patients with sarcoidosis and renal involvement,” was published in BMC Nephrology.
Optimal guidelines for renal sarcoisosis treatment lacking
Sarcoidosis is characterized by the formation of small clumps of inflammatory cells, called granulomas, that can affect various organs, including the kidneys, leading to inflammation and scarring.
Even though renal sarcoidosis, or sarcoidosis involving the kidneys, is uncommon, timely recognition and treatment of kidney inflammation are critical to prevent progression to kidney failure. However, “there are currently no established guidelines for optimal treatment and [appropriately controlled] trials are lacking,” the researchers wrote.
To learn more, researchers in the Netherlands conducted a retrospective analysis of data from 29 people with sarcoidosis and biopsy-proven kidney involvement who were followed at six hospitals in the country.
About two-thirds of the participants were men, and the median age at diagnosis of renal sarcoidosis was 56 years. Kidney problems were the first presentation of sarcoidosis in most patients (71%), while the remaining patients developed kidney involvement about two years after their initial sarcoidosis diagnosis.
Besides the kidneys, the lungs were the most commonly affected organ (48% of patients). Participants were followed up for a median of 50 months, or more than four years.
Most patients had chronic inflammation characterized by granuloma
At the time of renal sarcoidosis diagnosis, participants had elevated blood creatine levels and an estimated glomerular filtration rate of 23 mL/min/1.73 square meters, indicating severely decreased kidney function.
Other signs of kidney damage, including the presence of red blood cells, elevated white blood cell counts, and high levels of the albumin protein in the urine, were detected in 26.92% to 46.15% of the 26 patients with available data.
Participants also had elevated levels of SIL2R, a marker of immune system activation, and 45% had elevated blood calcium levels.
Results from kidney biopsies revealed that 76% of participants had chronic inflammation characterized by granulomas. All patients had interstitial fibrosis – scarring in the space around the kidneys’ functional structures – usually affecting up to 50% of the interstitial kidney tissue (83%).
About two-thirds of the patients had moderately active interstitial nephritis, or inflammation of interstitial tissue, and 14% had calcium deposits in the kidneys.
Although a large amount of fibrosis is seen, there is still a fair chance of improvement of kidney function in response to [prednisone].
All patients received corticosteroids (median initial prednisone dose of 60 mg/day) as the first-line treatment, with maximum improvement in kidney function seen after one month of treatment. After that, there was no further improvement.
“Although a large amount of fibrosis is seen, there is still a fair chance of improvement of kidney function in response to [prednisone],” the researchers wrote. “So a one to two month [prednisone] trial is justified in all patients.”
Prednisone dose was gradually decreased, reaching a dose of 10 mg after six months. Almost half of the patients (48%) experienced a relapse of renal sarcoidosis, after a median of seven months from the start of treatment. Nearly half of these patients were no longer on prednisone at the time of their first relapse.
Statistical analyses identified no significant predictors of early treatment response or of relapsing disease.
Overall, 45% of patients required treatment with additional immunosuppressive, corticosteroid-sparing drugs, most commonly azathioprine, mycophenolate mofetil, and methotrexate. These medications were given after the first or second relapse.
“As soon as the first relapse occurs, we suggest [starting] with a [steroid-sparing] agent, and [temporarily] doubling the dose of prednisone or [restarting prednisone] when already stopped,” the team concluded.
