Predictive Factors for Spontaneous Stone Passage in Diabetic Patients with Acute Ureteral Colic
Kidney stones are a common urological condition, with a prevalence of 8.8% in the United States population, according to data from the National Health and Nutrition Examination Survey (2007–2010). The prevalence of kidney stones is notably higher in individuals with obesity, diabetes, and metabolic syndrome. Specifically, the severity of type 2 diabetes has been associated with an increased risk of kidney stones. Despite this, the relationship between diabetes and spontaneous stone passage (SSP) in patients with acute ureteral colic remains poorly understood. This study aims to evaluate the association of diabetes with SSP and identify predictive factors for SSP in diabetic patients.
The study was conducted through a retrospective analysis of the Cleveland Clinic Foundation’s database of emergency renal colic visits. Patients who presented at the Emergency Department with urolithiasis between December 2010 and May 2013 were identified and included in the study. The Kidney Stone Registry, approved by the institutional review board of the Cleveland Clinic Foundation, was used to collect data. Patients with stones located only in the kidney, multiple ureteral stones, solitary kidney, pregnancy, fever, or signs of infection were excluded. A total of 660 patients with acute ureteral colic were enrolled, of whom 100 (15.2%) were diabetic.
Stone size was measured by an experienced endourologist using the axial diameter from computed tomography (CT) scans. Stone location and the degree of hydronephrosis were also assessed via CT scans. Patient characteristics, including age, gender, comorbidities, and laboratory test results, were obtained from electronic medical records. For diabetic patients, the level of hemoglobin A1c (HbA1c) was recorded. Additionally, ureteral wall thickness (UWT) at the stone site was measured from axial CT scans. UWT was defined as the point of greatest soft-tissue thickness around the circumference of the stone.
The study evaluated the association of diabetes with SSP within a 90-day follow-up period. Patients were followed at 2 to 4-week intervals for up to 90 days and monitored for worsening symptoms or renal function. SSP was defined as the passage of the stone from the ureter without any invasive interventions, confirmed by clinical manifestations, follow-up imaging, or telephone follow-up. Predictive factors for SSP in diabetic patients with acute ureteral colic were identified using univariate and multivariate analyses. Statistical analysis was performed using SPSS 25.0, with a P-value of less than 0.05 considered statistically significant.
Among the 660 patients enrolled, 418 (63.3%) were male, with an average age of 48.6 ± 15.0 years. Overall, 418 (63.3%) patients passed their stones spontaneously. The study found that neither diabetes diagnosis nor HbA1c levels were associated with changes in SSP rates. Stone location was a significant predictor of SSP, with stones located more distally in the ureter having the highest rates of spontaneous passage. Specifically, SSP rates were 75.6%, 58.3%, and 38.7% for distal, middle, and proximal ureteral stones, respectively. Stone size was also a major predictor of SSP, with larger stones associated with lower SSP rates. The SSP rates for stones 7 mm were 80.6%, 44.5%, and 16.3%, respectively.
When focusing specifically on diabetic patients with acute ureteral colic, the study found that smaller stone size, more distal stone location, and smaller UWT were statistically significantly associated with increased SSP rates. In univariate analysis, hydronephrosis and white blood cell count were not significant predictors of SSP in diabetic patients. Multivariate analysis confirmed that smaller UWT, smaller stone size, and more distal stone location were independent risk factors for SSP in diabetic patients.
The study’s findings are consistent with previous research on stone passage trends, including the influence of stone location and size on SSP rates. For example, a multicenter study demonstrated that the SSP rate for ureteral stones 7 mm. The current study observed similar trends, with SSP rates increasing as stone size decreased and stone location became more distal.
The study also highlighted the clinical significance of UWT in predicting SSP. Previous research by Yoshida et al. first reported that low UWT was associated with a significantly higher 4-week SSP rate compared to high UWT (76.4% vs. 14.7%, respectively). The current study confirmed that UWT is a superior predictor of SSP in diabetic patients. Ureteral obstruction by stones can lead to deteriorated renal function, febrile urinary tract infections, and even urosepsis. Diabetic patients are particularly at risk for these complications, making the identification of predictive factors for SSP crucial.
In conclusion, the study found that diabetes was not associated with changes in SSP rates. However, in diabetic patients with acute ureteral colic, smaller UWT, smaller stone size, and more distal stone location were independent risk factors for SSP. These findings have important implications for clinical decision-making, as they can help identify diabetic patients who may be suitable for conservative management. By reducing unnecessary surgeries and complications, this approach can offer both medical and financial benefits to the healthcare system. UWT and stone size are particularly important factors to consider when deciding on interventions such as extracorporeal shock wave lithotripsy or ureteroscopy in diabetic patients.
doi.org/10.1097/CM9.0000000000001456
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