Is there a ESWL link to diabetes, hypertension?
Emphasize the need for preventive steps
Two years after investigators from the Rochester, MN-based Mayo Clinic reported stunning data, suggesting that the use of extracorporeal shock wave lithotripsy (ESWL) to fragment kidney stones significantly increases the risk of diabetes and hypertension later on in life, clinicians remain unconvinced that there is a direct cause- and-effect relationship.
That investigation, lead by Amy Krambeck, MD, a urology resident at the Mayo Clinic, was a retrospective case control study that compared 19-year follow-up data of patients who underwent ESWL with patients whose kidney stones were treated by other methods. What investigators found was that the patients who underwent ESWL developed diabetes at nearly four times the rate of patients treated by other methods, and the ESWL group developed hypertension at about twice the rate of the other group.1
Clinicians tell Healthcare Imaging Update that while the findings are important, there were limitations in the study design that could have skewed results. "What [investigators] did was take patients treated with lithotripsy and compared them with patients who never received lithotripsy, but if you look at both groups, they weren't both the same in that the patients treated with lithotripsy had larger stones," explains Dean Assimos, MD, a professor in the Department of Urology at Wake Forest University Baptist Medical Center in Winston-Salem, NC.
Further complicating the picture, stresses Assimos, are the relationships between kidney stone disease and diabetes. "If you have stones, you are more at risk for developing diabetes, and if you have diabetes you are more at risk for developing kidney stones, so there are all these associations," says Assimos, noting that there are similar relationships between kidney stone disease and hypertension. "I think [researchers] uncovered something that warrants further study, but we can't point our finger and say that lithotripsy causes diabetes based on the limitations of the study."
Consider preventive steps
In the absence of more conclusive data, Rahmin Ari Rabenou, MD, a clinical assistant professor in the Department of Nephrology at New York University School of Medicine in New York City, believes that it is highly unlikely that ESWL actually causes diabetes. However, he is concerned about the possible impact of ESWL on hypertension — at least with respect to some patients.
"My concern with hypertension is probably less with respect to the person who gets one or two lithotripsy treatments. [However], I think the really bad stone formers who are getting lithotripsy after lithotripsy — I wouldn't be surprised if they are developing hypertension due to progressive renal scarring," says Rabenou.
Consequently, Rabenou believes the more important message from the Krambeck study is that more attention should be paid to prevention of future kidney stones in patients who are referred for lithotripsy. "If patients are having kidney stones, and they are needing lithotripsy, then they need to have an appropriate metabolic evaluation with that to develop strategies to prevent further stones from forming and passing," he says.
"You don't want to keep shocking peoples' kidneys, and I don't think that message has really gotten out into the urologic community or the public."
The typical patient who clearly should undergo a metabolic evaluation is someone who has experienced multiple kidney stones or has some underlying medical condition that makes them more at risk for developing stones, says Rabenou.
Reference
- Krambeck A, Gettman M, Rohlinger A, et al. Diabetes mellitus and hypertension associated with shock wave lithotripsy of renal and proximal ureteral stones at 19 years of followup. J Urology 2006; 175:1,742-1,747.
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