Changes in Urinary Lithogenic Features Over Time in Patients With Urolithiasis

Effects of metabolic syndrome on renal stone progression

PURPOSE

Studies on howmetabolic syndrome affects renal stone progression in untreated asymptomatic patients are lacking. Therefore, we investigated the effect of metabolic syndrome on changes in renal stone size.

MATERIALS AND METHODS

We retrospectively analyzed 820 patients with renal stones incidentally detected on CT during regular health examinations and who underwent follow-up CT evaluations for > 1 year. The patients were divided into two groups according to the presence of metabolic syndrome. Changes in stone size during the follow-up were assessed, and differences were compared according to various factors. Predictors of stone size change on CT were assessed using linear regression analysis.

RESULTS

Overall, 820 asymptomatic patients without a history of stone treatments and with a mean follow-up of 52.4 months were included. Of these, 104 (12.7%) had metabolic syndrome and 335 (40.9%) showed stone size increase during the follow-up. The stone size at diagnosis was not significantly different between patients with and without metabolic syndrome (225.3 ± 332.6 vs. 183.9 ± 310.2 mm³, p = 0.159); however, a significant difference was observed in the change in stone size at follow-up (148.5 ± 352.0 vs. 81.5 ± 222.4 mm³, p = 0.001). Multivariable analysis showed that age (β = - 0.11; - 5.92 to -0.69; p = 0.013), fasting glucose level ≥ 100 mg/dl (β = 0.11; 9.78-99.73; p = 0.017), and metabolic syndrome (β = 0.10; 9.78-99.73; p = 0.017) were factors predictive of stone size changes.

CONCLUSION

Metabolic syndrome, fasting glucose level ≥ 100 mg/dl and young age are positively related to renal stone size changes. Therefore, periodic follow-up and metabolic syndrome management are required in asymptomatic patients with renal stones, especially in young age.

Analysis of Patients with Urolithiasis Visiting the Emergency Department between 2014 and 2016 in Korea: Data from the National Emergency Department Information System

This study investigated the characteristics of patients with urolithiasis visiting an emergency department based on a national database system in Korea. This study spanned a period of three years from January 1, 2014 to December 31, 2016. A retrospective census was conducted using the National Emergency Department Information System for urolithiasis patients. Patient data, including age, sex, insurance type, emergency department visit date and time, discharge date and time, emergency department treatment result, visit flow, and hospitalization route, were extracted and analyzed. Overall, 103,981, 112,083, and 120,647 patients/year during the 2014-2016 study period visited an emergency department with a diagnosis related to urolithiasis. Total monthly emergency department visits ranged from 35,927 in August (highest) to 24,008 in February. Overall, 13.2% of patients were hospitalized and the hospitalization rate was stable (estimated annual percent change) over the study period. Patients aged <9 years or ≥70 years and those with medical aid had higher hospitalization rates. A higher number of visits occurred in the hot season, on weekends, and in the 6 a.m. and 8 p.m. time slots. This nationwide study revealed that the percentage of patients visiting an emergency department with urolithiasis was higher in August, in the early morning, and at weekends.

Chronological Trends in Clinical and Urinary Metabolic Features over 20 Years in Korean Urolithiasis Patients

Urolithiasis is common and is becoming more prevalent worldwide. This study assessed the chronological trends in clinical and urinary metabolic features over 20 years in Korean urolithiasis patients. We performed a retrospective analysis of 4,076 patients treated at our clinic from 1996 to 2015. Urinary metabolic data and stone analysis data were available for 1,421 and 723 patients (34.9% and 17.7%), respectively. Patients were categorized into 4 groups according to the date of initial diagnosis: group 1 (1996-2000, n = 897), group 2 (2001-2005, n = 1,018), group 3 (2006-2010, n = 1,043), and group 4 (2011-2015, n = 1,118). Incidental detection of uric acid renal stones has become more prevalent in the past 10 years, accompanied by an increase in body mass index and age at diagnosis. Similarly, the prevalence of diabetes mellitus and of hypertension increased from one group to the next throughout the study period. Levels of 24-hour urinary excretion of sodium, calcium, uric acid, and oxalate have decreased significantly over the study period. The incidence of urinary metabolic abnormalities also showed an identical tendency. The proportion of stones composed of uric acid increased over the study period. In conclusion, incidental detection of uric acid renal stones has become more prevalent in Korea in the past 20 years. Urinary excretion of lithogenic constituents and the incidence of urinary metabolic abnormalities have decreased significantly over this period.

Association between metabolic syndrome and the presence of kidney stones in a screened population

BACKGROUND

Components of metabolic syndrome have been associated with kidney stone disease, but little evidence is available to support a relationship between metabolic syndrome and kidney stone development in healthy large screened populations.

STUDY DESIGN

Cross-sectional analysis.

SETTING & PARTICIPANTS

Data were obtained from 34,895 individuals who underwent general health screening tests between January 2006 and December 2006 at the Asan Medical Center.

PREDICTOR

Metabolic syndrome was defined according to criteria established by the National Cholesterol Education Program Adult Treatment Panel III, American Heart Association, and National Heart, Lung, and Blood Institute.

OUTCOMES & MEASUREMENTS

The presence of kidney stones was evaluated using computed tomography or ultrasonography.

RESULTS

Of all those screened, 839 (2.4%) had radiologic evidence of kidney stones and metabolic syndrome was diagnosed in 4,779 (13.7%). The multivariable-adjusted OR for kidney stones increased with an increasing quintile of waist circumference and systolic/diastolic blood pressure (P < 0.001). Age, sex, hypertension, and metabolic syndrome status were independent risk factors for kidney stones. The presence of metabolic syndrome had an OR of 1.25 (95% CI, 1.03-1.50) for kidney stone prevalence. In participants with hypertension, the OR for the presence of kidney stones was 1.47 (95% CI, 1.25-1.71) compared with that for participants without hypertension after adjustment for other variables.

LIMITATIONS

Cross-sectional design, absence of stone composition.

CONCLUSION

Metabolic syndrome is associated with a significantly increased risk of kidney stone development. Our findings suggest the need for interventional studies to test the effects of preventing and treating metabolic syndrome on the risk of kidney stone development.

The Medical Management of Urolithiasis

Urolithiasis is increasing in prevalence and causes substantial morbidity and economic burden. Aside from “acute” stone episodes, urolithiasis should be regarded as a systemic disorder and investigated fully. Practical guidance is given for the medical investigation, diagnosis and treatment of urolithiasis. A single episode of urolithiasis should prompt a review of potential risk factors for recurrent disease and appropriate baseline investigations should be performed. Further biochemical tests may then be directed appropriately and allow individualised advice and treatment to be given to the patient with urolithiasis.