Urinary Stone Risk Factors Research Articles

Awareness of Urinary Stone Risk Factors Among the Adult Population of Jazan, Saudi Arabia: A Cross-Sectional Study.

Urolithiasis, a common clinical condition, has seen a global increase in prevalence in recent years. Urinary stones are common in hot climate areas like Saudi Arabia. This study aimed to assess the prevalence and awareness of risk factors for urinary stones in Jazan, Saudi Arabia. A cross-sectional study was conducted among 1000 Jazan adults between January and June 2022. A questionnaire was used to collect data on sociodemographics, urinary stone diagnosis, and awareness of risk factors. The overall prevalence of diagnosed urinary stones was 140 (14.0%). The prevalence was higher among patients who were older, married, had higher education, and were employees (all P<0.001). Participants who believed that hot weather (p = 0.012), sleeve gastrectomy (p = 0.049), and Saxenda injections (p = 0.000) increased the risk of stones had a higher prevalence. No association was found between stones and othersociodemographic factorsordietary habits. The main sources of knowledge were the internet (426, 42.6%) and education (155, 15.5%). The prevalence of urinary stones in Jazan is considerable (14.0%). Certain sociodemographic factors and beliefs about risk factors were associated with higher prevalence. Improving public awareness about the prevention and risk factors for urinary stones is crucial to controlling this health problem in high-risk communities.

Effect of a low-calorie diet on 24-hour urinary parameters of obese adults with idiopathic calcium oxalate kidney stones.

ABSTRACTPurpose:to evaluate the effect of low-calorie diet on 24-hour urinary metabolic parameters of obese adults with idiopathic calcium oxalate kidney stones.Materials and Methods:Adult idiopathic calcium oxalate stone formers, with body mass index (BMI) ≥30kg/m2 and a known lithogenic metabolic abnormality, were submitted to low-calorie diet for twelve weeks. After enrolment, anthropometric measures, serum exams, 24-hour urinary metabolic parameters and body impedance were collected one month prior to dietary intervention and at the end of twelve weeks. Correlations between weight loss, waist circumference loss, fat loss and variation in 24-hour urinary lithogenic parameters and calcium oxalate urinary supersaturation (CaOx SS) as per Tiselius equation were analysed.Results:From January 2017 to January 2018, 39 patients were enrolled to participate in this study. Median (range) prescribed diet was 1300 (1100-2100) Kcal/day. Mean age was 51.7±11.0 (29-68) years old and 69.2% were female. 30.8% of the participants shifted from obesity to BMI <30kg/m2 and none to BMI <25kg/m2. A significant correlation was found between baseline 24-hour urinary oxalate and weight (p=0.018) and BMI (p=0.026). No correlation was found between variation of weight, waist circumference, fat mass and 24-h urinary stone risk factors or CaOx SS.Conclusions:Short-term modest weight loss induced by twelve weeks of low-calorie diet is not associated with a decrease of 24-hour urinary lithogenic parameters in idiopathic calcium oxalate stone formers. Calcium oxalate urinary stone formation is probably multifactorial and driven by other factors than weight.

Urinary Tract Stones Risk Factors in Patients with Benign Prostatic Hyperplasia in West Java, Indonesia

Background: Urinary tract stones are common in patients with benign prostatic hyperplasia (BPH); therefore, an imaging test is needed for patients who have risk factors for the formation of urinary tract stones. The purpose of this study was to explore the factors associated with the presence of urinary tract stones in patients with BPH as information to conduct imaging tests.Methods: A cross-sectional quantitative analytic study was conducted on medical records of patients with BPH, both with and without urinary tract stones, or patients with urinary tract stones registered at the Department of Urology, Dr. Hasan Sadikin General Hospital, Indonesia, from 2015 to 2018. Data on age, body mass index, hypertension, use of antihypertensive drugs, diabetes mellitus, and hyperuricemia were collected and analyzed using the Mann-Whitney, Chi-square, Fisher exact test, and multivariate logistic regression statistical test to compare variables between BPH with and without urinary tract stones.Results: In total, 235 BPH patients were registered, of whom 74 (31.5%) had urinary tract stones. The median age was 64 years old. There was a relationship between age (p=0.030), diabetes mellitus (p=0.043), and the occurrence of urinary tract stones in patients with BPH. The most dominant risk factor was diabetes mellitus (OR=3.000, 95%CI 1.03-8.69).Conclusions: Age and diabetes mellitus are the risk factors for urinary tract stones in patients with BPH. BPH patients with diabetes mellitus are at a 3-fold risk for urinary tract stones. Diabetes mellitus in BPH patients is an indication to conduct imaging tests.

Risk factors in urinary stones: A case–control study

AbstractWhat are the urinary stones risk factors? Is there a relationship between nutritional, clinical and sociodemographic characteristics and urinary stones. The aims of this study are to determine risk factors in urinary stones, to examine the relationship between nutritional, clinical and sociodemographic characteristics and urinary stones and to compare these variables with those of healthy individuals. Urinary stones are multifactorial diseases. Determining the risk factors that cause urinary stones is vital to take preventive measures for urinary stones and avoiding recurrence. A 1:1 matched case–control study was performed and it included 123 cases and control group. The study data were collected with a questionnaire designed by the researchers. The study results suggested that 73.2% (n = 90) of the participants in the case group and 74.8% (n = 92) of the control group were male, the use of vitamin D was higher and the daily fluid consumption was lower in the case groups. The results of logistic regression analysis indicated that the incidence of urinary stones was 3.9 times higher (OR: 3.9, CI: 2.175–7.180) in patients who had a relative with urinary stones and 2.3 times higher in patients with previous urinary infection (OR: 2.309, CI: 1.200–4.443). It was concluded that a relative with urinary stones, prior urinary infection and usage of vitamin D were risk factors for urinary stones. Nurses should determine risk factors for urinary stones among all population groups and inform the public about the prevention of stone development.

Diet and Kidney Stones: The Ideal Questionnaire

Diet frequently contributes to patients’ urinary stone disease. It is important to determine when this is the case and when it is not, as failure to do so may delay the implementation of other, more appropriate therapies. When diet is thought to be involved, one of two approaches may be taken: (1) provide a general list of all possible dietary factors that influence the risk for all types of stones and let the patient decide which dietary change(s) are needed; or (2) prescribe specific modifications that address each patient’s need for change and their personal characteristics (i.e., urinary risk factors, type(s) of stones they have formed, dietary preferences, nutrient needs, etc.). The latter of these approaches is “minimally invasive” and is thus consistent with the goal of other therapies. However, this approach requires a rigorous appraisement of each patient’s diet and linkage, when possible, to urinary and other stone risk factors. When the collaboration of a registered dietitian nutritionist or other nutrition professional experienced in dietary assessment is not available, screeners or questionnaires may be useful. Unfortunately, there is no such tool that is validated for identifying dietary stone risk factors. The development of a brief, 40-item, stone-specific food screener is described. While further validation is needed, it may provide the basis for a standardized instrument that could be used more broadly; desired features of such an instrument are described.Patient Summary: Personalized nutrition therapy is useful in mitigating the effects or recurrence risk of many chronic diseases. It is also useful in stone disease, a condition with highly variable risk expression, even among patients who form the same types of stones. A standardized and validated stone-specific dietary assessment tool would be valuable in clinical management and in research studies involving the description of patients’ diets and dietary intervention.

The relationship between urine specific gravity, urine pH, and blood uric acid levels to the type of urinary stones of patients with urolithiasis at Sanglah Hospital, Bali, Indonesia

Background: Urine specific gravity, urine pH, and blood uric acid levels are risk factors for urinary tract stones. The urinary tract stones are formed due to the concentration of a solute exceeds its ability to remain in solution, resulting in supersaturation and crystallization. This study aims to determine the relationship between urine specific gravity, urine pH, and blood uric acid levels to the urinary stone's types in patients with urolithiasis at Sanglah HospitalMethods: A retrospective cross-sectional study was conducted among 95 subjects by using secondary data from the medical records in the period June 2017-2018 at Sanglah Hospital. The urolithiasis patient who met the inclusion and exclusion criteria were enrolled in this study. Data were analyzed by the Mann-Whitney Test and Kruskal-Wallis Test using SPSS version 17 for Windows.Results: The average age was 55±11 years old. Most of respondents were male (70.5%), normal Body Mass Index (BMI) (89.5%), urine pH &lt;7 (75.7%), and mixed type of urinary stones (48.4%). There was a statistically significant relationship between the type of uric acid stone (p=0.029), blood uric acid levels (p=0.003), phosphate stone type (p=0.026), and magnesium stone (p=0.010) with urine pH. Besides, there was a statistically significant relationship between ammonium stone and blood uric acid levels types (p=0.022). A statistically significant difference was also found between stone types based on urine pH (p=0.013) in multivariate analysis.Conclusion: There is a significant relationship between urine pH and stone type on the incidence of urolithiasis in Sanglah Hospital in June 2017-2018, thereby increasing the incidence of urolithiasis.

Hypomagnesuria is Associated With Nephrolithiasis in Patients With Asymptomatic Primary Hyperparathyroidism.

The pathogenesis of nephrolithiasis in primary hyperparathyroidism (PHPT) remains to be elucidated. The latest guidelines suggest parathyroidectomy in patients with asymptomatic PHPT with hypercalciuria (> 400 mg/d) and increased stone risk profile. The objective of this work is to evaluate the association of urinary stone risk factors and nephrolithiasis in patients with asymptomatic sporadic PHPT and its clinical relevance. A total of 157 consecutive patients with sporadic asymptomatic PHPT were evaluated by measurement of serum and 24-hour urinary parameters and kidney ultrasound. Urinary parameters were tested in the univariate analysis as continuous and categorical variables. Only hypercalciuria and hypomagnesuria were significantly associated with nephrolithiasis in the univariate and multivariate analysis adjusted for age, sex, body mass index, estimated glomerular filtration rate, parathyroid hormone, 25-hydroxyvitamin D, serum calcium, and urine volume (odds ratio, OR 2.14 [1.10-4.56]; P = .04; OR 3.06 [1.26-7.43]; P = .013, respectively). Hypomagnesuria remained associated with nephrolithiasis in the multivariate analysis (OR 6.09 [1.57-23.5], P = .009) even when the analysis was limited to patients without concomitant hypercalciuria. The urinary calcium/magnesium (Ca/Mg) ratio was also associated with nephrolithiasis (univariate OR 1.62 [1.27-2.08]; P = .001 and multivariate analysis OR 1.74 [1.25-2.42], P = .001). Hypomagnesuria and urinary Ca/Mg ratio had a better, but rather low, positive predictive value compared with hypercalciuria. Hypomagnesuria and urinary Ca/Mg ratio are each associated with silent nephrolithiasis and have potential clinical utility as risk factors, besides hypercalciuria, for kidney stones in asymptomatic PHPT patients. The other urinary indices that have been commonly thought to be associated with kidney stones in PHPT are not supported by our results.

Dietary risk factors for urinary stones in children.

As the incidence of urinary stone disease in children is increasing, identifying dietary risk factors becomes vitally important, especially in the context of targeting interventions to reduce risk for stone formation. Indiscriminant dietary restrictions are not appropriate for paediatric patients. Although large, prospective studies are still needed to better quantify dietary risk factors for paediatric stone formers, a number of smaller studies provide data to identify common risk factors to help prevent stone formation, while minimizing inappropriate dietary restrictions. Interpretation of 24-h urine samples to identify individualized dietary risk factors is crucial for implementing a strategy for prevention of further urinary stone formation in children. Clinicians should avoid generalized dietary restrictions in stone-forming children uninformed by laboratory data.

Calcium Kidney Stones are Associated with Increased Risk of Carotid Atherosclerosis: The Link between Urinary Stone Risks, Carotid Intima-Media Thickness, and Oxidative Stress Markers.

Previous studies have suggested that kidney stone formers are associated with a higher risk of cardiovascular events. To our knowledge, there have been no previous examinations of the relationship between carotid intima-media thickness (IMT) and urinary stone risk factors. This study was aimed toward an investigation of the association between dyslipidemia, IMT, and 24-hour urinalysis in patients with calcium oxalate (CaOx) or calcium phosphate (CaP) stones. We prospectively enrolled 114 patients with kidney stones and 33 controls between January 2016 and August 2016. All patients were divided into four groups, according to the stone compositions—CaOx ≥ 50% group, CaP group, struvite group, and uric acid stones group. Carotid IMT and the carotid score (CS) were evaluated using extracranial carotid artery doppler ultrasonography. The results of a multivariate analysis indicated that a higher serum total cholesterol (TC) and low-density lipoprotein (LDL) were all associated with lower urinary citrate and higher CS in both the CaOx ≥ 50% and CaP groups. Higher serum TC and LDL were also associated with increased serum 8-OHdG levels in both groups. The levels of carotid IMT and CS in the CaOx ≥ 50% and CaP groups were all significantly higher than in the controls. These findings suggest a strong link between dyslipidemia, carotid atherosclerosis, and calcium kidney stone disease.

Correlation analysis between urinary system stone formation and dietary factors in Hainan province

Objective To investigate the relationship between urinary calculi formation and dietary factors in Hainan province. Methods From March 2017 to June 2018, 100 patients with urinary calculi in the hospital were selected as the observation group, and 100 non-calculus patients admitted to the hospital were selected as a control group. Questionnaire survey was used to investigate the dietary structure of the subjects and to analyze the correlation with the occurrence of stones. Results Univariate analysis showed that patients with stones and non-calculus patients had sweets. The frequency, sea fish diet, old fire soup, beverage and other dietary habits were significantly different (P<0.05). Logistic regression analysis showed that sea fish diet, sweets, old soup, and beverage were the main risk factors for urinary stones (P< 0.05). Conclusions There is a certain correlation between urinary calculi and dietary factors in Hainan province. It is necessary to pay attention to dietary balance and increase the amount of exercise in time to reduce the risk of urinary calculi. Key words: Urinary Calculi; Diet; HAINAN

Identification of new urinary risk markers for urinary stones using a logistic model and multinomial logit model.

Risk assessment for urinary stones has been mainly based on urinary biochemistry. We attempted to identify the risk factors for urinary stones by statistically analyzing urinary biochemical and inflammation-related factors. Male participants (age, 20-79years) who visited Nagoya City University Hospital were divided into three groups: a control group (n = 48) with no history of stones and two stone groups with calcium oxalate stone experience (first-time group, n = 22; recurring group, n = 40). Using 25-µL spot urine samples, we determined the concentrations of 18 candidate urinary proteins, using multiplex analysis on a MagPix® system. In univariate logistic regression models classifying the control and first-time groups, interleukin (IL)-1a and IL-4 were independent factors, with significantly high areas under the receiver operating characteristic curve (1.00 and 0.87, respectively, P < 0.01 for both). The multivariate models with IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) showed higher areas under the receiver operating characteristic curve (0.93) compared to that for the univariate model with IL-4. In the classification of control, first-time, and recurrence groups, accuracy was the highest for the multinomial logit model with IL-4, GM-CSF, IL-1b, IL-10, and urinary magnesium (concordance rate 82.6%). IL-4, IL-1a, GM-CSF, IL-1b, and IL-10 were identified as urinary inflammation-related factors that could accurately distinguish control individuals from patients with urinary stones. Thus, the combined analysis of urinary biochemical data could provide an index that more clearly evaluates the risk of urinary stone formation.

Urinary stone risk factors in the descendants of patients with kidney stone disease.

Evidence has indicated that immediate family members of nephrolithiasis patients had high opportunity to develop stones. However, they are usually not regarded to be at risk, since it is unclear if there are any lithogenic abnormalities found in non-stone-forming nephrolithiasis relatives. Our aim was to investigate urinary metabolic abnormalities in the children of nephrolithiasis patients, compared with the general population. The 24-h urinary metabolic profile was studied for 28 calcium oxalate nephrolithiasis patients (NL) and 46 of their descendants (ND), as well as 40 non-stone-forming volunteers (V) and 34 of their descendants (VD). There was no difference between age, gender, and serum creatinine between NL vs. V (parental groups) and ND vs. VD (descendant groups). High urinary oxalate in nephrolithiasis and urinary calcium in their descendants was detected. In addition, an elevated urinary excretion rate of calcium, phosphate, protein, and albumin, along with low citrate excretion and high urinary supersaturation was observed in both the nephrolithiasis patients and their descendants. Approximate 17.8-24.4% of the nephrolithiasis descendants had a urinary supersaturation higher than the nephrolithiasis level, but none was found in VD group. The level of urinary supersaturation index was correlated with urinary protein and albumin excretion in nephrolithiasis family. It was demonstrated that nephrolithiasis offspring carried several urinary metabolic risks predisposing to stone formation which are similar to their parents, and about one in every five nephrolithiasis children had nephrolithiasis level urinary supersaturation.

Reference intervals for stone risk factors in 24-h urine among healthy adults of the Han population in China.

The aim of the study was to establish reference intervals for 24-h urinary stone risk factors in the healthy Chinese Han population. From May 2013 to July 2014, we collected and analyzed 24-h urine samples from healthy adult Han population during a cross-sectional study across China. The protocol for analysis of 24-h urine included volume, pH, oxalate, citrate, sodium, potassium, chloride, calcium, phosphorous, creatinine, urate, magnesium, the ion activity products of calcium oxalate (AP(CaOx) indexs) and calcium phosphate (AP(CaP) indexs). We calculated the reference intervals according to the Clinical and Laboratory Standards Institute (CLSI) 2008 guidelines and compared them with those recorded in other studies. A total of 132 male and 123 female healthy subjects with a mean (SD, range) age of 52.4 (15.2, 19-89) years were eligible in the final analysis. Men had higher 24-h excretion of creatinine, calcium, urate and phosphorus and lower levels of citrate, magnesium, chloride, sodium and potassium than women. AP(CaOx) indexs and AP(CaP) indexs were significantly higher among men than women. When urinary findings were compared with the reference intervals, most of our data showed a high abnormality rate, especially for creatinine, calcium, citrate, magnesium, chloride, sodium and potassium. The present study revealed the normal metabolic status for stone risk factors of the Chinese Han population. It is therefore necessary for each country or region to define their own reference intervals for comparison of stone risk factors between patients and healthy subjects.

Different effects of γ-linolenic acid (GLA) supplementation on plasma and red blood cell phospholipid fatty acid composition and calcium oxalate kidney stone risk factors in healthy subjects from two race groups with different risk profiles pose questions about the GLA-arachidonic acid-oxaluria metabolic pathway: pilot study.

Fatty acid (FA) composition of phospholipids in plasma and red blood cells (RBC) can influence calciuria, oxaluria and renal stone formation. In this regard, the ratio of arachidonic acid (AA) and its precursor linoleic acid (LA) appears to be important. Administration of γ-linolenic acid (GLA) has been shown to increase the concentration of dihomo-gamma linoleic acid (DGLA) relative to AA indicating that it may attenuate biosynthesis of the latter. Such effects have not been investigated in race groups having difference stone occurrence rates. Black (B) and white (W) healthy males ingested capsules containing linoleic acid (LA) and GLA, for 30days. Plasma and RBC total phospholipid (TPL) FA profiles, serum and 24h urine biomarkers of hypercalciuria and urinary stone risk factors were determined on days 0 and 30. Data were tested for statistical significance using GraphPadInstat version 3.02. Concentration and percentage content of DGLA in plasma TPL increased in W but not in B. Arachidonic acid (AA) did not change in either group. There was no change in calcium excretion in either group but oxalate and citrate excretion increased in W. We suggest that elongation of GLA to DGLA may occur more rapidly than desaturation of DGLA to AA in W and that depressed activity of the enzyme elongase may occur in B. Calciuric and citraturic effects may be dependent on the quantity of LA or on the mass ratio of LA/GLA in the FA supplement. Questions about the mooted DGLA-AA-oxaluria pathway arise. We speculate that there exists a potential for using GLA as a conservative treatment for hypocitraturia. The observation of different responses in B and W indicates that such differences may play a role in stone formation and prevention.

Water and other fluids in nephrolithiasis: State of the art and future challenges

ABSTRACT Adequate hydration, as to maintain urinary volume over 2 L/day, has long been considered as the cornerstone medical prescription for preventing nephrolithiasis. However, scientific evidence about what kind of water stone formers should drink and about the effects of other beverages on urinary stone risk factors is sometimes unclear. Moreover, the recommendation that water therapy prevents kidney stone recurrence relies on only one randomized controlled trial, even if more epidemiologic and basic science studies seem to support this assumption. Therefore, in this review we analyze current evidence that support water therapy in nephrolithiasis and we highlight the possible effects of different types of water and other beverages on lithogenic risk, giving some practical recommendations for what stone formers should be advised to prevent recurrence.

Systemic endothelial function measured by flow-mediated dilation is impaired in patients with urolithiasis.

Some in vitro and animal studies have shown endothelial dysfunction in hyperoxaluria models indicating its role in pathogenesis of urolithiasis and relation to CVD. The aim of this study was to investigate endothelial function in patients with urolithiasis in relation to urinary stone risk factors and metabolic parameters. A total of 120 subjects without any known CVD (60 with urolithiasis and 60 healthy subjects) were included into study. Fasting blood and 24-h urine samples were collected to study metabolic parameters (glucose and lipids) and urine stone risk factors (oxalate, citrate, uric acid, and calcium, pH). Endothelial function was assessed as flow-mediated dilation (FMD) at the brachial artery. Age, sex, and body mass index were similar in patients and controls. Of urine stone risk factors, oxalate and citrate were higher in patients than controls. Fasting blood glucose, total LDL cholesterol, and triglyceride were higher, and HDL cholesterol was lower in patients than controls. Although within normal limits systolic blood pressure was higher in patient group, patients with urolithiasis had a lower %FMD than controls. Percent FMD was negatively correlated with urinary oxalate/creatinine ratio (p=0.019, r=-0.315), calcium/creatinine ratio (p=0.0001, r=-0.505) age (p<0.001, r=-0.694), BMI (p<0.001, r=-0.838), total cholesterol (p<0.001, r=-0.559), and triglyceride (p<0.001, r=-0.529). Urine oxalate/creatinine ratio was positively correlated with age (p=0.01, r=0.327) and calcium/creatinine ratio with BMI (p=0.001, r=0.410). This is the first study demonstrating endothelial dysfunction in human subjects with urolithiasis. This indicates a possible predictive role of urolithiasis in future development of cardiovascular diseases.

Patients Attending Shared Medical Appointments for Metabolic Stone Prevention Have Decreased Stone Risk Factors.

Shared medical appointments (SMAs) have decreased patients' wait time to initial stone clinic appointment, standardized education, and increased exposure to nutrition therapy. We assessed the effectiveness of SMAs in reducing patients' urinary stone risk factors. Patients who established care in our stone clinic in an SMA between March 2012 and August 2015 were sequentially identified. After eliminating those without follow-up urine collections or whose urinary creatinine excretion between the two collections varied by >40%, 113 patients were included (M:F 63:50; 54 ± 15 years; body mass index [BMI] 30.6 ± 6.7). Results from before and after the SMA were compared with those from a similar cohort of patients who attended individual patient appointments (IPAs) for their first stone clinic visit (n = 63; M:F 37:26; 54 ± 14 years; BMI 30.1 ± 8.2). All patients received individualized medical therapy for stone prevention. After medical and nutritional therapy, SMA patients with elevated risk(s) at baseline achieved significant reductions in uric acid, calcium, and sodium; p ≤ 0.001 for all. Those with low urine magnesium, low urine volume, low urine pH, and/or low urine citrate at baseline achieved increases; p ≤ 0.0008 for all. IPA patients with elevated baseline risk factors achieved reductions in oxalate and uric acid (p ≤ 0.004 for both) but neither calcium nor sodium and an increase in citrate (p = 0.003) but not magnesium. Patients from SMAs reduced their stone recurrence risk and compared favorably with patients from IPAs. Contributing factors may include shorter time from stone event to appointment and more standardized education for patients attending SMAs.

Kinetics of calcium oxalate crystal formation in urine.

It is routinely observed that persons with increased urinary stone risk factors do not necessarily form uroliths. Furthermore, stone formers can present with urinalyses that do not reflect the clinical picture. We explain this discrepancy by differences in crystallization kinetics. In 1162 urines, crystallization of Ca-oxalate was induced according to the BONN-Risk-Index (BRI) method. The urine's relative light transmissivity (RLT) was recorded from 100% at start of titration to 95% due to nuclei formation and crystal growth. From the RLT changes, a measure of the thermodynamic inhibition threshold of crystal formation (BRI) and of crystal growth kinetics is derived ("turbidity slope" after crystallization onset). On average, subjects presenting with a low inhibition threshold, i.e., high BRI, also present significantly higher crystal growth rates compared with subjects in lower BRI classes. Only subjects in the highest BRI class show a lower growth rate than expected, probably due to a depletion of supersaturation by massive initial nucleation. With increasing thermodynamic risk of crystal formation (i.e., increasing BRI) due to an imbalance between inhibitors and promoters of crystal formation, an increase in the imbalance between inhibitors and promoters of crystal growth (i.e., increasing growth rate) is observed. Both lead to an increased urolith formation risk. Healthy subjects with increased BRI are an exception to this trend: their urine is thermodynamically prone to form stones, but they show a kinetic inhibition preventing nuclei from significant growth.

Clinical and demographic factors associated with compliance and subsequent urinary metabolic changes in first-time ureteral stone formers

Dietary and lifestyle modifications are widely prescribed to prevent recurrence of urolithiasis, although little is known about the clinical and demographic factors associated with patient compliance and urinary metabolic changes. The present study assessed the clinical and demographic factors influencing compliance with a modified diet and lifestyle in first-time ureteric stone formers as well as determined the effects of compliance on urinary stone risk factors. We retrospectively reviewed the medical records of 53 patients presenting with ureteric calcium stones. Using a self-completed questionnaire, patients were classified according to compliance with seven recommendations for modifying diet and lifestyle into good compliance group (complied with ≥ three recommendations) and poor compliance group. Before (on a random diet) and after prescribing the modifications, 24 hour urine samples were collected from those in the good and poor compliance group. The stone size at presentation and initial treatment modality were closely associated with patient compliance (P=0.019, P=0.027, respectively). Citrate excretion significantly increased in the good compliance group after adopting modifications (P=0.012), whereas the poor compliance group did not show a statistically significant difference. Moreover, patients in the poor compliance group showed significantly increased urinary calcium excretion by the end of the study (P=0.040). After adjustments for age, sex, body mass index, and metabolic abnormality status, poor compliance was found to be an independent risk factor for persistence or development of hypocitraturia (OR: 3.885; 95% CI: 1.102~13.694; P=0.035). In conclusion, our results imply that patient education programs regarding diet and lifestyle should be tailored to the individual’s clinical and demographic characteristics.

MP34-04 INHIBITION OF GLYCOLATE OXIDASE REDUCES URINARY OXALATE EXCRETION IN A MOUSE MODEL OF PRIMARY HYPEROXALURIA TYPE 1

INTRODUCTION AND OBJECTIVES: Cumulative evidences indicate a tight association between urinary stone and dyslipidemia. Statins are widely used in clinical treatment of dyslipidemia. It is interesting and also important to know whether statin use can reduce the risk of upper urinary tract stone in patients with dyslipidemia. METHODS: We used data sourced from Longitudinal Health Insurance Database, which consists of one million randomly selected subjects from the National Health Insurance Research Database of Taiwan. Health Insurance System of Taiwan covers approximately 23 million people (98% of population). From 1997 to 2001, a total of 11785 subjects, 5926 males and 5859 females, with age 18-year-old or older were identified as dyslipidemia. All subjects did not have previous diagnosis of urinary stone. A cohort of 23570 (2 for each subject with dyslipidemia) age and gender matched subjects without the diagnosis of dyslipidemia and urinary stone were enrolled as the control group. All subjects were followed up to the end of 2009 with a minimal follow-up of 8 years. Multi-variables, including statin use, hypertension, and diabetes mellitus (DM), were taken into account. A Cox proportional hazard regression model was used to calculate the risk of upper urinary tract stone in study and control groups. RESULTS: At the end of follow-up, 1817 (15.4%) of the 11785 dyslipidemia subjects and 2445 (10.4%) of the 23570 control subjects developed upper urinary tract stones. After adjusting for age, gender, hypertension and DM, dyslipidemia was associated with a significantly increased risk of urinary stone (hazard ratio 2.086, 95% confidence interval, 1.929 2.256, p< 0.0001). The dyslipidemia subjects were further stratified into statin user group and non-statin user group. Nine hundred and sixty eight (15.1%) of the 6401 statin users and 849 (15.8%) of the 5384non-statin users developedupper urinary tract stones.Dyslipidemia patients who received statin treatment were not less likely to develop upper urinary tract stone than the patients who never used statin (hazard ratio 1.074, 95% confidence interval, 0.976 1.181, p 1⁄4 0.1430). CONCLUSIONS: Dyslipidemia is an independent risk factor for upper urinary tract stone. The findings of this study suggest that the use of statin cannot reduce the risk of upper urinary tract stone in patients with dyslipidemia.