WASHINGTON: One of the popular methods of treating kidney stones -- pulverizing the stones into sandlike substance using ultrasound shock waves -- has been found to increase diabetes and hypertension risks in patients later in life.
In one of the longest ever follow-up studies on this mode of treatment conducted by the Mayo Clinic at Rochester, researchers found that patients who underwent the procedure -- better known as lithotripsy -- developed diabetes at almost four times the rate of those whose kidney stones were treated by other methods. These patients also developed high blood pressure about 50 per cent more often than a group treated by other methods. The study details have been reported in The Journal of Urology.
The diabetes risk can be related to the number of shocks (which can be in hundreds or thousands) given to blast the stone, the researchers said, while hypertension can be attributed to treatment of stones in both kidneys but not to the total number of shocks.
The Mayo Clinic said in a news release that the researchers are sounding an alert on the side effects of lithotripsy and that the findings are "completely new."
Dr Amy Krambeck, a co-author of the study and a lead researcher, said earlier studies had not identified diabetes as a complication for lithotripsy, while hypertension has been associated with the procedure.
Krambeck and her team would want an animal model to find out how precisely the shock waves resulted in diabetes and hypertension. As for now, they assume that therapy damages the insulin-producing cells in the pancreas, as the shock waves may pass through this gland. The risk of hypertension is increased when the kidneys are scarred by the treatment affecting their ability to secrete hormones like renin, which influence blood pressure.
The researchers underscore the need for post-treatment follow-up as these complications can arise much later.
The researchers, however, do not advise getting rid of the procedure altogether. They say lithotripsy has an important role in treating kidney stones despite the risks.
Recent scientific studies have concluded that kidney stones can be found in about 10 per cent of men and 5 per cent of women aged 70 and younger. It can be an isolated medical event or part of some systemic biochemical disorder.
Some one million people in the U.S. have undergone lithotripsy procedure since its introduction in the country in 1984.
There are other techniques to treat stones in the kidneys and the urinary tract, including removing it with an instrument inserted through an opening made in the patient's back. Yet another method is to insert a catheter into the urethral opening, into the bladder and into the ureter and then breaking up the stone using ultrasound or laser energy. These procedures are invasive, unlike lithotripsy, and require longer stay in the hospital.
Krambeck says, newer machines used in lithotripsy give more focused shocks, but it has not been established whether these machines offer less risk. She says there is need for elaborate study, but there is no need to ban or stop the procedures altogether.
She also points out to the other modes of treatment available. "It all has to do with genetic makeup, diet, and lifestyle. Once a person forms a stone, he or she needs a complete metabolic evaluation to understand why. Then we can give medication to prevent a second stone."
