Renal stone disease in a Swedish district during one year

The Urological Association of Asia clinical guideline for urinary stone disease

The Urological Association of Asia, consisting of 25 member associations and one affiliated member since its foundation in 1990, has planned to develop Asian guidelines for all urological fields. The field of stone diseases is the third of its guideline projects. Because of the different climates, and social, economic and ethnic environments, the clinical practice for urinary stone diseases widely varies among the Asian countries. The committee members of the Urological Association of Asia on the clinical guidelines for urinary stone disease carried out a surveillance study to better understand the diversity of the treatment strategy among different regions and subsequent systematic literature review through PubMed and MEDLINE database between 1966 and 2017. Levels of evidence and grades of recommendation for each management were decided according to the relevant strategy. Each clinical question and answer were thoroughly reviewed and discussed by all committee members and their colleagues, with suggestions from expert representatives of the American Urological Association and European Association of Urology. However, we focused on the pragmatic care of patients and our own evidence throughout Asia, which included recent surgical trends, such as miniaturized percutaneous nephrolithotomy and endoscopic combined intrarenal surgery. This guideline covers all fields of stone diseases, from etiology to recurrence prevention. Here, we present a short summary of the first version of the guideline - consisting 43 clinical questions - and overview its key practical issues.

The economics of stone disease

The rising prevalence of kidney stone disease is associated with significant costs to healthcare systems worldwide. This is in part due to direct procedural and medical management costs, as well as indirect costs to health systems, patients, and families. A number of manuscripts evaulating the economics of stone disease have been published since the 2008s International Consultation on Stone Disease. These highlight costs associated with stone disease, including acute management, surgical management, and medical management. This work hopes to highlight optimization in care by reducing inefficient treatments and maximizing cost-efficient preventative strategies.

The influence of environmental conditions on the incidence of renal colic in Rome

INTRODUCTION

The aim of this study was to investigate the effect of three major environmental variables (temperature, humidity, air pressure) on the probability of onset of renal colic (RC) in a large cohort of patients in Rome.

METHODS

The records of 2682 patients discharged by the Emergency Department (ED) of the University Hospital of Tor Vergata, Rome, from January 2007 to November 2009 with the main diagnosis of reno-ureteric colic associated with a proven calculus, were retrospectively evaluated. The climatic parameters (average humidity, average air pressure and daily minimum, medium and maximum temperature) were recorded in a second, independent database. RC events were grouped by weeks and months and analysed for a total period of 35 months and 153 weeks.

RESULTS

Two thousand five hundred and fourteen patients out of 2682 had a proven urolithiasis. RC events were observed more likely in the warmer months, from the second half of June to the first half of September, compared with the colder months. Although the weekly model showed a positive correlation (R2 = 0.134) between the average increase of environmental temperature and RC incidence, the monthly model was much more convincing (R2 = 0.373). We found no statistically significant correlation between humidity and air pressure and the incidence of RC.

CONCLUSIONS

This study demonstrates that an increase in average environmental temperature is associated with a significant increase in the number of episodes of RC seen in the ED at both weekly and monthly time intervals. The average humidity and air pressure were not found to be associated with an increased incidence of RC.

Changes in urinary stone composition in the Tunisian population: a retrospective study of 1,301 cases

BACKGROUND

Studies that evaluate the effect of age on stone composition are scarce. The aim of this study was to highlight the changes in epidemiological characteristics (stone composition and location) of urolithiasis according to patients' age.

METHODS

We studied 1,301 urolithiasis patients with age ranging from 6 months to 92 yr (781 males and 520 females). Stone analysis was performed using a stereomicroscope and infrared spectroscopy to determine the morphological type and molecular composition of each stone.

RESULTS

The annual average incidence of new stone formation was 31.7 per 100,000 persons. In 71.8% of cases, calculi were located in the upper urinary tract. Compared to other age groups, children and old men were more affected by bladder stones. Calcium oxalate monohydrate was the most frequent stone component, even though its frequency decreased with age (59.5% in young adults and 43.7% in the elderly, P<0.05) in favor of an increase in uric acid stones (11.5% in young adults and 36.4% in the elderly, P<0.05). Struvite stones were rare (3.8%) and more frequent in children than in adults.

CONCLUSIONS

The analysis of these data showed that urinary stones in Tunisian patients are tending to evolve in the same direction as the stones in patients from industrialized countries.

Economics of stone disease/treatment

OBJECTIVES

Urolithiasis is a considerable economic burden for health systems, especially in industrialised countries where the incidence of stone disease has increased during the last few decades, and probably will further increase for several reasons.

METHODS

The survey was based on investigations in collaboration with a German health insurance company and on a literature search (PubMed, and the author's collection of proceedings of urolithiasis conferences: The keywords included economics, cost, urolithiasis, nephrolithiasis, renal stone disease, metaphylaxis, recurrence) during 1999-2011. In all, 1221 articles were found but only those cited here were sufficient for the purpose of the study. Due to the nature of the subject it is not possible to give levels of evidence, as economic data on stone treatment cannot be obtained with randomised studies.

RESULTS

The costs for the treatment and diagnosis of stones vary tremendously among different healthcare systems. Several calculation models showed that metaphylaxis is medically and economically effective when used rationally. Rational metaphylaxis is restricted to patients with a high risk of recurrence (brushite, uric acid, cystine and infected stones, patients with residual fragments after stone treatment and recurrent calcium oxalate stone formers).

CONCLUSIONS

For the groups identified, metaphylaxis is cost-effective in almost all healthcare systems, but the cost saved differs. The savings increase even more when adding the economic loss avoided from days off work due to treatment of recurrent stones. In most countries, stone frequency must exceed one stone per patient per year before medical therapy is more cost-effective than dietary measures.

[Changes in kidney stones type according to sex and age in Tunisian patients]

BACKGROUND

Studies that evaluate the effect of age and gender on the stone composition are scarce. The aim of this study is to highlight the modification of epidemiological characteristics of this pathology according to patients' sex and age.

PATIENTS AND METHODS

We studied 1269 urolithiasic patients ranging from 6 months to 92 years old and known as having urinary stones (752 males and 517 females). Stone analysis was performed respectively using a stereomicroscope and infrared spectroscopy to determine, respectively, the morphological type and molecular composition of each.

RESULTS

The annual average incidence of new stone formation was 30.25 per 100,000 inhabitants. In 1041 patients (81%), calculi were located in the upper urinary tract. Children and old man were more affected by bladder stone. Calcium oxalate monohydrate remains the most frequent stone component even if its frequency fell according to age (63.2% in teenagers and 40.6% in elderly [p<0.05]) in favour of the increase of uric acid stones (3,5% in teenagers and 41.5% in elderly [p<0.05]). Struvite stones were rare (3.5%) and more frequent in children.

CONCLUSION

The analysis of these data shows that urinary stones in Tunisia are tending to evolve in the same direction as in industrialized countries.

[Climate and epidemiological characteristics of renal colic attendances in an urban setting in Spain]

OBJECTIVES

To address the real incidence of RC episodes in our setting and its relationship with several epidemiological, seasonal and climatic factors.

MATERIAL AND METHODS

We analyzed 156,687 attendances in the emergency unit of Hospital Infanta Cristina (Parla, Madrid, Spain), from the opening of the unit in 07/04/2008 to the date of analysis (28/03/2010). Date of birth, sex, history of previous urinary lithiasis episodes, main cause and date of attendance were collected. Daily climate parameters (maximum daily temperature and percent relative humidity) were recorded.

RESULTS

A total number of 1,866 RC episodes (1.19% of all attendances) were recorded during the study period. Age ranged from 15 to 94 years, median 39. RC episodes were more prevalent in male population (58.4% vs 41.6% in females respectively, p<0.001). No differences were observed with regard to previous history of RC. A modest but significant rise in RC incidence was observed during summer and autumn. No significant correlation was observed between monthly or seasonal number of RC attendances and the climatic parameters studied.

CONCLUSIONS

RC incidence in our setting is similar to the previously reported in the literature. A modest but significant higher incidence of renal colic episodes were observed during summer and autumn seasons, although no significant relationship was attributed to temperature and humidity values. Absence of dramatic seasonal changes in incidence can be explained by the "non-extreme" weather conditions in the studied setting.

Ambient temperature as a contributor to kidney stone formation: implications of global warming

Nephrolithiasis is a common disease across the world that is becoming more prevalent. Although the underlying cause for most stones is not known, a body of literature suggests a role of heat and climate as significant risk factors for lithogenesis. Recently, estimates from computer models predicted up to a 10% increase in the prevalence rate in the next half century secondary to the effects of global warming, with a coinciding 25% increase in health-care expenditures. Our aim here is to critically review the medical literature relating stones to ambient temperature. We have categorized the body of evidence by methodology, consisting of comparisons between geographic regions, comparisons over time, and comparisons between people in specialized environments. Although most studies are confounded by other factors like sunlight exposure and regional variation in diet that share some contribution, it appears that heat does play a role in pathogenesis in certain populations. Notably, the role of heat is much greater in men than in women. We also hypothesize that the role of a significant human migration (from rural areas to warmer, urban locales beginning in the last century and projected to continue) may have a greater impact than global warming on the observed worldwide increasing prevalence rate of nephrolithiasis. At this time the limited data available cannot substantiate this proposed mechanism but further studies to investigate this effect are warranted.

Cost-Effectiveness of Medical Expulsive Therapy Using Alpha-Blockers for the Treatment of Distal Ureteral Stones

OBJECTIVE

Medical expulsive therapy (MET) has recently emerged as an efficacious and safe option for the initial management of ureteral stones. The objective of this study was to assess the cost-effectiveness of MET compared with conservative therapy for the treatment of ureteral stones using international cost data from the United States and four European countries.

MATERIAL AND METHODS

A decision analysis model was built with the use of TreeAge Pro 2004 software with linear success rate assumptions. The likelihood of spontaneous passage of ureteral stones according to their size and location was estimated with the use of data derived from a published meta-analysis. The estimated cost of ureteroscopy (URS) in the United States ($4973) was based on the mean cost of 121 consecutive cases performed at a large metropolitan hospital. URS costs for other countries were obtained from a published international survey. The cost of tamsulosin ($2.08 per day), currently the most commonly used medical expulsive agent, was estimated as a mean of the costs obtained from two national pharmacy chains. MET and conservative therapies were compared with the use of one-way and two-way sensitivity analyses.

RESULTS

In the United States, MET using tamsulosin resulted in a $1132 cost advantage over observation. MET maintained its cost advantage even in countries where the cost of URS is much lower than in the United States. Two-way sensitivity analysis showed that MET remained cost-effective even with very low rates of spontaneous passage, minimal benefit of MET, or low cost of URS.

CONCLUSION

MET is a cost-effective strategy for the management of distal ureteral stones--even those with a low rate of spontaneous passage--providing another incentive for initial "facilitated observation" before embarking on surgical intervention.

Do weather conditions influence the onset of renal colic? A novel approach to analysis

BACKGROUND/AIM

To investigate the seasonal variations of the incidence of renal colic by a computerized analysis of cyclic climatic features.

METHODS

1,163 consecutive patients with acute renal colic were studied. Eigendecomposition and signal reconstruction of district temperature and humidity were performed to establish any cyclic variation. Average temperatures and humidity values were calculated at time periods of 15, 30, 45 and 60 days preceding each renal colic.

RESULTS

Patients were allocated to groups every 30 days, since eigendeanalysis suggested that intervals of this duration have homogeneous climatic features. With an average time period of 15 days preceding each renal colic, a positive correlation coefficient of temperature (r = +0.75 with CI 0.31-0.93, p < 0.005) and a cubic relationship at the regression analysis (R = 82.4%, p = 0.015) were found with the onset of colics. We observed a negative correlation between humidity and renal colic (rho = -0.70 with CI -0.92 to -0.21, p < 0.01), with an inverse relation as regression model (R = 57.9%, p < 0.05).

CONCLUSIONS

We demonstrated an association between the onset of renal colics and exposure to hot and dry weather, particularly when temperatures rose above 27 degrees C and relative humidity fell below 45%.

Seasonal variations in urinary calculi attacks and their association with climate: a population based study

PURPOSE

In this nationwide population based study we used 5-year data on urinary calculi patient visits to emergency departments in Taiwan to investigate the seasonal variation in urinary calculi attacks and the association with 5 climatic parameters.

MATERIALS AND METHODS

Comprehensive details on total admissions to emergency departments were obtained from the Taiwan National Health Insurance Research Database (1999 to 2003), providing monthly urinary calculi attack rates per 100,000 of the population. Subgroups of urinary calculi incidences were created based on gender and 3 age groups (18 to 44, 45 to 64 and 65 years old or older). Following adjustment for time trend effects, evaluation of the monthly urinary calculi attack rates and the effects of climatic factors was performed using auto-regressive integrated moving average regression methodology.

RESULTS

The seasonal trends in the monthly urinary calculi attack rates revealed a peak in July to September, followed by a sharp decline in October, with the auto-regressive integrated moving average tests for seasonality demonstrating significance for each gender group, for each age group and for the whole sample (all p <0.001). Although significant associations were found between ambient temperature, atmospheric pressure and hours of sunshine vis-à-vis monthly urinary calculi attack rates for the total population, after adjustment for trends and seasonality, ambient temperature was found to be the sole major factor having any positive association with the monthly attack rates.

CONCLUSIONS

We conclude that seasonal variations do exist in the monthly urinary calculi attack rates for all age and gender populations, and that following time series statistical adjustment, only ambient temperature had any consistent association with monthly attack rates.

Economics of stone management

Cost, in addition to efficacy and morbidity, has become an important factor in determining the best therapeutic modality for a variety of disease states. A comprehensive literature search finds that, in general, for staghorn calculi, percutaneous nephrostolithotomy is more cost-effective than shock wave lithotripsy (SWL) for stones greater than 2 cm in any dimension, while SWL may be cost-effective for smaller stones. For ureteral stones, observation is the least costly treatment strategy. Among surgical options, ureteroscopy is less costly than SWL. For single and recurrent stone formers, medical prophylactic strategies involving drug therapy are more costly than conservative therapy involving dietary measures alone. However, drug strategies yield fewer stone recurrences.

[Economic aspects of evidence-based metaphylaxis]

The calculation model which we developed for the cost of stone therapy and metaphylaxis in Germany some years ago with a social health insurance company is based on estimates of stone incidence, types and recurrence rates, actual costs for stone removal, and metaphylaxis (based on data from a district of the social health care system). There are 200,000 stone recurrences per year in Germany. Costs for treatment of these stones amount to $687,000,000. Stone metaphylaxis reduces the recurrence rate by some 40%. The annual cost for stone removal could be lowered by $275,300,000. Metabolic evaluation/metaphylaxis amount to $70,100,000 per year, resulting in a net saving of $205,200,000. In 1997, there were 96 days off work per stone patient resulting in 5,800,000 days off work in Germany per year. Metaphylaxis is not only medically effective in stone formers but also can lower health care cost significantly. Although health care conditions may vary from country to country, in principle this calculation model is applicable also to other countries.

Immediate versus deferred radiological investigation after acute renal colic: a prospective randomized study

OBJECTIVE

The timing of radiological assessment after acute renal colic is controversial. The aim of this study was to investigate the value of immediate versus deferred radiological imaging and to compare morbidity rates after an attack of acute renal colic.

MATERIAL AND METHODS

Between September 2001 and December 2002 all 686 patients with acute renal colic attending our university hospital were registered. Of these, 172 patients rendered pain-free after analgesic injection were randomized to either immediate or deferred radiological investigation. All patients received a questionnaire encompassing questions on consumption of analgesics, impact of symptoms on normal daily activity (including working ability), need for additional emergency department visits and hospitalization. Stone treatments were registered.

RESULTS

The incidence of renal colic was 0.9/1,000 inhabitants per year. In total, 74% of all patients became pain-free after analgesic injection. Morbidity was low among the randomized patients, and did not differ between the immediate or deferred radiological investigation groups. In both groups, the duration of impairment of normal daily activities and analgesic consumption was a median of 2 days. In the immediate group, 14% needed another emergency visit and 4% were hospitalized. Corresponding figures for the deferred group were 15% and 7%. In the immediate group, 17% had stone treatment, compared with 8% in the deferred group.

CONCLUSION

For most patients with acute renal colic, parenteral analgesia resulted in complete symptom resolution. When initial medical treatment was successful, patient morbidity was low. In these patients, immediate radiological imaging did not lead to reduced morbidity compared with radiological imaging after 2-3 weeks.

Effect of season, age, and gender on renal colic incidence

Our objective was to examine the effect of ambient temperature, age, and gender on the incidence of emergency department (ED) renal colic visits. We retrospectively analyzed a database of 15 New Jersey EDs from January 1, 1996 to December 31, 2002. We analyzed the number of renal colic visits as a fraction of total visits in monthly intervals. We used the Chi-squared test and Pearson's correlation coefficient, with P<.05 taken as statistically significant. Of the 3.5 million patient visits in the database, 30,358 (0.9%) had renal colic. Renal colic visits were 16% more likely in warmer than colder months (P<.001) and this effect was greatest in older patients and males. We conclude that higher ambient temperature, older age and male gender are associated with increased incidence of ED renal colic visits. Advice to patients, especially older males, to avoid dehydration particularly during hot weather may help prevent bouts of renal colic.

Epidemiological profile, mineral metabolic pattern and crystallographic analysis of urolithiasis in Kuwait

This study was conducted to determine the epidemiological profile of urolithiasis in Kuwaiti patients and the associated metabolic abnormalities favouring stone formation in this patient population. Between 1986 and 1994, a total of 421 Kuwaiti patients were studied in Al-Amiri renal stone laboratory. The mineral composition of stones was determined using a combination of stereoscopic microscopy and infrared spectrophotometry. Mineral metabolic screen (MMS) was available in 306 (72.7%) of those patients. The average annual incidence of new stone formation in Kuwaiti patients was 23.9 per 100,000 population. The incidence was only 6.9 per 100,000 population in those from pediatric age group, 33.4 in adults and 73.6 in the elderly. The frequency of new stone formation was higher among males as compared to females at different age groups. Calcium oxalate (CaO) constituted 72.1% of renal stones encountered in adults as compared to only 52.1% and 40.7% in elderly and pediatric age groups. Eighty four patients had recurrent and/or high stone load. Detailed family history was available in 57 of those 84 patients and was suggestive of strong family aggregation of stone disease in 30 (53%) patients. The proportion of urate stones was 15.4% of all stones formed and constituted a major cause of renal stones in children (24.1%), adults (14.4%) and elderly (12.5%). Cystine stones were found in 10 patients (2.4%). Hyperuricemia was detected in 1/3 of patients from pediatric age group. In adults, 89 (38.4%) of 232 patients had abnormal MMS, of which hyperuricosuria with or without hyperuricemia accounted for 79.8% of those abnormalities. In elderly patients, metabolic disorders were detected in 7 (17.5%) of the 40 patients. In the latter group, all except one, had hyperuricosuria with or without hyperuricemia. Cystinuria, distal renal tubular acidosis (d-RTA) and hyperparathyroidism constituted 6.6% of metabolic abnormalities in the patients studied. Primary abnormalities of upper and lower urinary tract was detected in 6% of adult patients as compared to 47% in children and 30% in the elderly. In conclusion; the incidence rate of new stone former in Kuwait is significantly lower from that reported in Europe and USA. This latter finding and the high familial aggregation of urolithiasis in our area constitute a cogent argument against the role of hot climate in the pathogensis of urolithiasis and are in favour of genetic predisposition. Isolated hyperuricosuria was detected in 17% of idiopathic CaO stone formers. The latter finding is of practical importance since red-meat is a common food item in our area and restriction of purine-intake may help to decrease the frequency of urate and CaO stone formation in predisposed patients.

Recurrences during a 10-year follow-up after first renal stone episode

Each of 92 patients in a Swedish district served by only one hospital had been treated for their first renal stone in 1977 and was evaluated 10 years later. Recurrent stone formation during the observation period was observed in 26% of the patients, with no difference between men and women. Of all the patients who had sought medical advice in 1977 because of urinary stone colic, 51% were experiencing their first stone episode. Ten years later 37% of the original patients were still classified as single stone formers. The recorded recurrence rate was lower than that previously reported in the literature.

Prevalence of urolithiasis in a Finnish district. An epidemiologic study of adults in Tampere

Information on the prevalence of urolithiasis in a general population was obtained in an investigation of 5252 persons in the Finnish city of Tampere from September 1980 to February 1982. The study was based on a questionnaire delivered to every 37th citizen in the age groups 20-69 years and to 45-year-old and 65-year-old persons taking part in a health screening program. Persons with a history of urolithiasis were compared with healthy controls. The prevalence figures were 3.0% for men and 1.8% for women aged 20-69 years. The corresponding figures for the 45-year-old group were 4.2% and 1.2% and for the 65-year-old group they were 5.2% and 2.2%.

Randomized trial of allopurinol in the prevention of calcium oxalate calculi

In a double-blind study, we examined the efficacy of allopurinol in the prevention of recurrent calcium oxalate calculi of the kidney. Sixty patients with hyperuricosuria and normocalciuria who had a history of calculi were randomly assigned to receive either allopurinol (100 mg three times daily) or a placebo. After the study, the placebo group had 63.4 percent fewer calculi (P less than 0.001), whereas the allopurinol group had 81.2 percent fewer calculi (P less than 0.001). During the study period, the mean rate of calculous events was 0.26 per patient per year in the placebo group and 0.12 in the allopurinol group. When the treatment groups were compared by actuarial analysis, the allopurinol group was found to have a significantly longer time before recurrence of calculi (P less than 0.02). We conclude that allopurinol is effective in the prevention of calcium oxalate stones in patients with hyperuricosuria. The large reduction in the frequency of calculi in the placebo group underscores the positive treatment bias that regularly occurs in trials of prophylaxis against renal calculi when historical controls are used.

Urinary calculi: microbiological and crystallographic studies

Although referred to as "urinary calculus disease", the formation of stone in the urinary tract is not caused by a single etiological agent. As such, diverse clinical investigations to diagnose the cause of stone formation must be carried out and the course of management after diagnosis must inevitably be different in each case. This review will cover all aspects of calculus formation, but will give particular attention to calculi caused by infection of the urinary tract with urease-producing bacteria. This is a recurrent, potentially life-threatening disease which has led clinicians to refer to the condition as "stone cancer". Because the etiology of infection stones is so different from stones caused by metabolic disorders, the two disease patterns should be considered separately, a fact often overlooked in epidemiological studies of stone formation. The importance of analysis of calculi as an aid to management is thus emphasized; identification of stone type will help to indicate appropriate therapy. A review of methods of analysis will be covered, particularly crystallographic analysis. Inhibition of bacterial urease as a means of management of infection stones will be discussed together with problems encountered and brighter hopes for the future.

The severity of infection stones compared to other stones in the upper urinary tract

A retrospective study of the case records of 391 adult patients with spontaneously passed or surgically removed concrements from the upper urinary tract during the period 1982-1983 was performed. According to chemical analysis, 66% of the stones were calcium stones, 30% were infection stones, 4% were uric acid/urate stones and 1% were cystine stones. Of the infection stones 12 (10%) were staghorn calculi. The infection stones placed a greater strain on the patients than the calcium stones. Thus, infection stones were significantly more often recurrent stones and required surgery significantly more often than the calcium stones. Only 6% of the patients with infection stones had proved abnormalities predisposing to upper urinary tract infection. Urinary tract infection with a urease-producing microorganism was detected in only 52% of the patients with infection stones. As infection with a urease-producing microorganism is a prerequisite for the formation of infection stones in the urinary tract a careful microbiological investigation to find and treat the infection responsible for the stone formation is mandatory.

Acute ureteral colic and fluid intake

In the treatment of acute ureteral colic opinions differ regarding the consequences of fluid intake. This study was undertaken to evaluate a possible relationship between fluid load and the pain. One group of patients received 3 liters of fluid intravenously, while in another group all fluids were withheld. No intergroup differences as regards pain was found after 6 hours of observation.

Urolithiasis in general practice. An epidemiological study from a Norwegian district

The incidence of urolithiasis associated with a stone colic has been investigated in general practice in a rural, partly industrialized area of Eastern Norway. Two cases per year per 1000 inhabitants were observed. The incidence showed seasonal variation, with a maximum during the winter and autumn months in four consecutive years. As reported by others, there was an excess of male patients (2.7:1) and of persons with sedentary occupations. A peak stone incidence was found in the middle-aged groups (30-60 years). The probably unselected patient group from the incidence registration was compared with a selected material of patients referred for recurrent stone disease. The unselected patients from general practice showed about 1/5 the median number of stone episodes and 1/4 the median duration of the disease.