12 Renal & Urology News
FEBRUARY 2013
Lower glucose/ESRD risk continued from page 1
ering group was defined by local guidelines. The target level for the intensive group was 6.5% or less. Patients assigned to the intensive group started on gliclazide MR (20-120 mg daily) and were required to discontinue any other sulfonylurea. The timing, selection, and dose of all other treatments used to achieve the target were at the discretion of the treating physician. Mean systolic blood pressure was 1.6 mm Hg lower on average in the intensive group compared with the standard group, and adherence to BP-lowering drugs was slightly higher (75.2% vs. 72.5%), but the investigators said “it is unlikely that these small differences accounted for the observed effects.”
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“The new data presented here provide the strongest evidence yet that intensive glucose-lowering regimens may protect against the development of ESRD, one of the most devastating and expensive complications of diabetes,” the researchers noted. “The results were consistent across different levels of HbA1c, kidney function, and albuminuria.” Commenting on the new study, Barry I. Freedman, MD, Chief of the Section on Nephrology at Wake Forest School of Medicine in Winston-Salem, N.C., noted that the finding that intensive glucose lowering slows progression to ESRD is important and consistent with other studies demonstrating renoprotective effects of intensive glucose lowering. “Anything that can reduce the number of patients with diabetes who progress to dialysis is critically important
Emergency stone visits continued from page 1
to 384 per 100,000 individuals, a 101% increase; among non-whites, the rate increased from 112 to 165 per 100,000 individuals, a 47% increase. Among the various age groups examined in the study (younger than 25, 25-44, 45-64, and older than 64 years), patients aged 25-44 years had the largest increase in ED visit rates: from 258 to 599 per 100,000 individuals, a 132% increase. The proportion of urolithiasis patients imaged with CT increased from 21% in 1998-2000 to 71% in 2007-2009. “The increased use of CT for evaluation of a common clinical syndrome such as urolithiasis raises important clinical questions,” the researchers wrote. “CT clearly provides important and accurate diagnostic information for physicians caring for patients with suspected urolithiasis. However, repeated use of CT evaluations for patients with recurrent urolithiasis contributes to increased radiation exposure for patients, as well as an increase in costs.” The researchers identified these trends by analyzing data from the National Hospital Ambulatory Medical Care Survey and the National Health and Nutrition Examination Survey (NHANES). Their study also showed that medical expulsive therapy was used in 14% of emergency patients with a urolithiasis diagnosis in 2007-2009. Among NHANES participants who reported a history of kidney stones, 22.4% had passed three or more stones. The study revealed no seasonal or regional variation in ED visit rates for urolithiasis during the study period.
because diabetes is the number one cause of end-stage renal disease in the Western world,” said Dr. Freedman, who has been involved in numerous studies of chronic kidney disease in patients with diabetes but did not participate in the new study. In addition, he noted that the reduction in heavy proteinuria was quite striking, but this does not necessarily translate into preservation of renal function. “Frankly, development of end-stage renal disease is due to a reduction in kidney function. Reduction in heavy proteinuria may be a different phenomenon. Protein in the urine does not always equate with loss of kidney function.” One of the confounding issues in this study was whether the reduction in progression to dialysis or development of heavy proteinuria was strictly due to
Emergency Visits for Stones Emergency department (ED) visit rates for urinary stones increased for both men and women from 1992 to 2009, but the rise was greater for women. Shown here are the numbers of ED visits per 100,000 individuals. 1992 2009
400 350 300 250 200 150 100 50 0
231
393 Men
127
289 Women
Source: Fwu CW, Eggers PW, Kimmel PL, et al. Emergency department visits, use of imaging, and drugs for urolithiasis have increased in the United States. Kidney International; published online ahead of print.
The new findings are consistent with those of a study published last year in European Urology (2012;62:160-165). In an analysis of data from 12,110 participants in the 2007-2010 NHANES, researchers led by Charles D. Scales, Jr., MD, of the University of California-Los Angeles, found that 8.8% of respondents
Use of computed tomography imaging rose substantially from 1998 to 2009. reported a history of kidney stones, up from 5.2% reported by 1994 NHANES respondents. According to the investigators, “the increase is likely related to dietary and lifestyle factors.” The prevalence increased for both men and women. The 2007-2010 data revealed that 10.6% of men and 7.1% of women reported having kidney stones, up from 6.3% and 4.1%, respectively, in 1994.
Kidney stones were more common among obese individuals than among normal-weight subjects (11.3% vs. 6.1%). Compared with normal-weight individuals, obese respondents had a 55% increased risk of kidney stones. “Presuming obesity as a marker for the metabolic syndrome, which is linked epidemiologically and physiologically to risk of kidney stones, the epidemic of obesity in the United States is a likely explanation for the dramatic rise in the prevalence of stone disease,” Dr. Scales and his colleagues noted. In an interview with Renal & Urology News, Dr. Scales praised the study by Dr. Kirkali’s group as “another important contribution to our understanding of the increasing burden of kidney stone disease in the United States.” Although surgical technique has advanced rapidly over the past two decades, he added, “the tide of kidney stones has risen unabated.” Dr. Scales, who is a Robert Wood Johnson Foundation/VA Clinical Scholar at UCLA’s David Geffin School of Medicine, noted that the current
the lower blood sugars, Dr. Freedman told Renal & Urology News. In his view, the lower systolic BP achieved in the intensive group could have influenced findings, as it is well established that lowering BP slows development and progression of diabetic kidney disease. The intensive group showed greater adherence to BP-lowering drug therapy, and this could reflect greater therapeutic adherence in general, which could have had a positive effect on outcomes, he said. Furthermore, unlike previous studies that used many different medications to lower blood sugar, the new study assigned patients in the intensive group to receive one particular sulfonylurea, Dr. Freedman noted, adding that it is possible that this drug has a unique effect that benefited the intensive group. ■
treatment paradigm focuses on the acute, symptomatic kidney stone, and largely ignores the chronic underlying metabolic derangements that lead to periodic stone “attacks.” “Stone disease is now as prevalent as diabetes in the United States, and more prevalent than coronary artery disease or stroke,” he said. “A greater emphasis on the public health aspects of stone disease, and the role of primary and secondary prevention, appears indicated.” A number of intriguing findings emerge from the new study, Dr. Scales said. For example, ED visits appear to be increasing more rapidly among women than in men, although men still have more ED visits overall. “While the reasons for this difference remain unclear, the finding is consistent with several studies documenting changing differences in the gender distribution of stones,” he said. “Obesity, diabetes, and other dietary/lifestyle factors are strongly associated with the risk of stone disease, and the impact of these factors may be greater in women than men. As would be expected from the known racial/ethnic differences in risk of stone disease, white individuals had the highest rate of ED visits throughout the study period.” ■
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