Prevalence and risk factors of urinary stones in Koreans

Urinary Calculi: A Microbiological and Biochemical Analysis at a Tertiary Care Hospital in Eastern Nepal

Background

The occurrence of urinary tract infection in presence of urolithiasis is frequently noted; however, microbial agents of urolithiasis and their antimicrobial susceptibility patterns remain underinvestigated. This study aimed to identify the microorganisms isolated from urine and stone matrices to determine their antimicrobial susceptibility, to find the association between the pathogens of urine and stone matrices, and to perform the biochemical analysis of stones.

Methods

A total of 88 cases of urolithiasis admitted for elective stone removal at Department of surgery, B.P. Koirala Institute of Health Sciences (BPKIHS), were enrolled. Preoperative urine culture and postoperative stone culture were performed. Isolation, identification, and AST were done by the standard microbiological technique. Further qualitative biochemical analysis of stones was also attempted.

Result

Among 88 stone formers recruited, culture of urine, whole stone, and nidus yielded the growth of bacteria 44, 32, and 30, respectively. Bacteria isolated from urine culture correlated with those from stone matrices with a sensitivity of 90%, specificity of 79.69%, PPV of 63.64%, and NPV of 95.45%. Escherichia coli (46.7%) was the most common bacteria followed by Klebsiella pneumoniae (16.7%) and Proteus mirabilis (13.3%) from urine and stone cultures. Almost all the uropathogens isolated were susceptible to commonly used antibiotics. Calcium oxalate (84.1%) was common biochemical constituent found in stone formers followed by calcium oxalate + phosphate (8%).

Conclusions

The association of microorganism isolated from urine and nidus culture was significant that can predict the source of infective stone; however, in some cases, microorganisms and the antimicrobial susceptibility pattern from urine and nidus were different. This study emphasizes the use of appropriate antimicrobial agents to prevent the regrowth of residual stones and minimize the risk of infectious complications after surgical removal of stones.

Low-Dose Unenhanced Computed Tomography with Iterative Reconstruction for Diagnosis of Ureter Stones

PURPOSE

To study the clinical application of low-dose unenhanced computed tomography with iterative reconstruction technique (LDCT-IR) on renal colic in the emergency department.

MATERIALS AND METHODS

We conducted a prospective, single-blinded, randomized, and non-inferiority study. From March 2014 to August 2015, 112 patients with renal colic were included, and were randomized to either LDCT-IR (n=46) or standard-dose unenhanced CT (SDCT) (n=66) groups. The accuracy of urolithiasis diagnosis was the primary endpoint of this study. Radiation dose, size and location of the stone, hydronephrosis, other diseases except urolithiasis, and results of treatment were analyzed between the two groups.

RESULTS

The average effective dose radiation of SDCT was approximately four times higher than that of LDCT-IR (6.52 mSv vs. 1.63 mSv, p<0.001). There was no significant difference in the accuracy of ureteral stone diagnosis between the two groups (LDCT-IR group: 96.97% vs. SDCT group: 98.96%, p=0.392). No significant difference was observed regarding the size and location of a stone, hydronephrosis, and diagnosis of other diseases, except urolithiasis. False negative results were found in two LDCT-IR patients and in one SDCT patient. In these patients, stones were misread as vascular calcification, and were difficult to diagnose because evidence of hydronephrosis and ureteral dilatation was not found.

CONCLUSION

LDCT-IR, as a first-line imaging test, was non-inferior to SDCT with respect to diagnosis of ureter stones, and was clinically available for the evaluation of renal colic.

Dietary risk factors for urolithiasis in Korea: A case-control pilot study

Purpose

Dietary factors are one of the main causes of urolithiasis. However, little research has evaluated dietary factors related to urolithiasis in Korea. We investigated the various dietary risk factors for urinary stone formation in Korean people.

Materials and Methods

We conducted a prospective case-control pilot study. A total of 27 patients newly diagnosed with urolithiasis and 20 applicants without urolithiasis were designated as the patients and the control group, respectively. A face-to-face survey was carried out using a food-frequency questionnaire. After adjustment for physical activity level and total energy intake, multivariate logistic regression models were applied to search for risk factors for urolithiasis.

Results

There were no significant differences between the two groups in gender, age, body mass index, family history, or total energy intake. The physical activity level of the control group was significantly higher than that of the patients (p=0.012). The results of the multivariate logistic regression model demonstrated that intake of carbohydrate (odds ratio [OR], 1.055; 95% confidence interval [CI], 1.012–1.099), protein (OR, 1.101; 95% CI, 1.001–1.211), and cereals (OR, 1.012; 95% CI, 1.002–1.023) could increase the risk for urolithiasis.

Conclusions

A higher intake of carbohydrate, protein, and cereal may increase the risk of urinary stone formation among Korean people.

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.

Urolithiasis in patients suffering from malignant hematologic diseases

PURPOSE

We performed this study in order to evaluate the incidence and characteristics of urolithiasis in patients with malignant hematologic diseases.

MATERIALS AND METHODS

Nine hundred one patients who underwent medical treatment for malignant hematologic disease and 40,543 patients who visited the emergency room and without malignant hematologic diseases were included in our study. The patients with malignant hematologic diseases were divided into two groups depending on their primary treatment. Group I included patients with acute and chronic leukemia (AML, ALL, CML, CLL) for which chemotherapy and steroid therapy was necessary, and group II included patients with anaplastic anemia and myelodysplastic syndrome and who had undergone repeated transfusion for treatment. Comparisons were made between the two groups in respect to the incidence of urolithiasis and the stones' radiopacity.

RESULTS

Twenty nine patients (3.2%) of the 901 malignant hematologic patients were diagnosed with urolithiasis, compared to 575 patients (1.4%) of 40,543 emergency room patients. There was a significant increase of the incidence of urolithiasis in the malignant hematologic group. Compared to the general patients, the patients with malignant hematologic diseases had a higher rate of radiolucent stones (46.6% versus 16.3%, respectively), and the difference was significant.

CONCLUSION

The incidence of urolithiasis for malignant hematologic patients was significantly higher than that for the control group.

Risk factors for urinary tract calculi in Trinidad

OBJECTIVE

To identify risk factors for urinary tract stones in Trinidad and Tobago.

METHODS

A consecutive series of patients presenting to institutions in Trinidad for the management of proven urinary tract calculi was interviewed by questionnaires designed to obtain data on age, gender, ethnicity, occupation, stone location, a family history of stone disease, a past history of certain medical diseases and a semiquantitative estimate of the magnesium intake in food, 'over the counter' drugs and drinking water. An equivalent number of patients attending the same institutions for follow-up and verified from hospital records as having a previous radiological diagnosis of urinary tract stones, as well as a group of asymptomatic members of the community working in the same area, underwent the same interview. Chi-square, anova and Kruskal-Wallis tests were used to examine differences between the groups. Multiple logistic regression analysis was used to determine persistence of the significance of these differences after controlling for confounding variables.

RESULTS

Data sufficient for analysis were obtained for 122 previous and 102 prospective patients and 102 controls. The mean age of the patients was 32 years. The ratio of males to females was 0.9-1.8:1 for the affected groups, but significantly more males than females had calculi in the lower urinary tract (19%vs. 6%; P = 0.004). More patients (30%) than controls (7%) gave a positive family history of urinary tract stone disease (P < 0.001). Affected persons had a lower dietary magnesium intake (P = 0.003), which accounted for a significantly lower total magnesium intake (P = 0.02). Logistic regression analysis of the variables studied indicated that independent predictors of the disease were a positive family history (P = 0.001), total magnesium intake (P = 0.001) and age (P < 0.001).

CONCLUSION

A low magnesium intake and a positive family history are highly predictive of urinary tract calculi in this population.