SAN DIEGO—Athletes who use anabolic steroids may seriously damage their kidneys, according to new findings presented at the American Society of Nephrology’s Renal Week conference.
“Athletes who use anabolic steroids and the doctors caring for them need to be aware of the potentially serious risks to the kidney,” said lead investigator Leal Herlitz, MD, Assistant Professor of Pathology at Columbia University Medical Center in New York.
Reports of professional athletes who abuse anabolic steroids are increasingly common. Most people know that using steroids is not good for their health, but until now their effects on the kidneys have not been known.
Dr. Herlitz and her colleagues recently conducted the first study describing injury to the kidneys following long-term abuse of anabolic steroids. They studied a group of 10 bodybuilders (six Caucasians and four Hispanics) who used steroids for many years and experienced proteinuria and severe reductions in kidney function.
The men were seen between 1999 and 2009 and had highly muscular physiques. All were long-term anabolic androgenic steroid abusers, had proteinuria of 1g/day or greater, and a renal biopsy diagnosis of focal segmental glomerulosclerosis (FSGS). The average BMI was 34.7 kg/m2 (range: 27-43). The men presented with proteinuria (mean 10.1 g/day, range 1.3- 26.3 g/day) and renal insufficiency (mean serum creatinine 3.0 mg/dL, range: 1.3- 7.8 mg/dL). Five men presented with full nephritic syndrome.
It is well known that FSGS typically occurs when the kidneys are overworked. The kidney damage observed in this group of bodybuilders had similarities to that seen in morbidly obese patients, but appeared to be even more severe. Renal biopsy revealed FSGS in nine of the patients; four of the nine patients also had glomerulomegaly. One patient had glomerulomegaly alone. Three biopsies showed collapsing lesions of FSGS and four had perihilar lesions. Seven of the 10 men had tubular atrophy of 40% or greater and interstitial fibrosis.
“It is important to recognize that all the people in this series were long-term abusers, ranging from eight to 20 years of use,” explained Dr. Herlitz, who presented study findings at the 2009 Renal Week conference here. “So, it is unlikely that someone who uses for a few months is going to be significantly harmed. I really have no basis for estimating the prevalence of this problem and I’m hoping that this study will bring attention to the issue so that people will be aware of the entity and we can start to better understand who is affected and why.”
Follow-up data were available for eight of the 10 patients. The mean follow-up was 2.2 years. One patient progressed rapidly to end-stage renal disease (ESRD) and seven patients received renin-angiotensin system (RAS) blockade. One of these seven also received corticosteroid therapy. All seven patients who received RAS blockade discontinued anabolic androgenic steroids and reduced their exercise regimens. They also lost weight and had a stabilization or improvement in serum creatinine and a decrease in proteinuria.
Although the bodybuilders who discontinued steroid use experienced improvement in their kidney abnormalities, one individual with advanced kidney disease progressed to ESRD and required dialysis. One subject started taking steroids again and suffered a relapse, developing progressive proteinuria and renal insufficiency.
Compared with historical controls who had obesity-related glomerulopathy, FSGS in these bodybuilders was a more severe form of the disease with higher creatinine and proteinuria levels at presentation. These patients also tended to have more glomerular and tubulointerstitial scarring.
The researchers proposed that extreme increases in muscle mass require the kidneys to increase their filtration rate, placing harmful levels of stress on the kidneys. “As in obese patients, the increased strain on the kidney from the elevated body mass leads to hyperfiltration injury,” Dr. Herlitz explained.
It is also likely that steroids have direct toxic effects on the kidneys. “Numerous animal models have shown adverse effects of androgens on the kidneys and we believe that the anabolic steroids themselves may be directly nephrotoxic,” she said.