Approaches to Self‐Management in Chronic Illness

Management of a chronic medical condition is a complex process and requires coordinated action between healthcare providers and patients. This process is further complicated by the fact that an increasing number of patients suffer from multiple chronic conditions. Self‐management involves active participation of the patients in the everyday care of the symptoms of their illness(es) and medical treatments, as well as maintaining general health and prevention of progression of medical conditions. Managing the psychosocial consequences of illness is also an important component of self‐management. Data have demonstrated that enhancing self‐management improves quality of life, coping, symptom management, disability, and reduces healthcare expenditures and service utilization. To foster self‐management, potential barriers to implementation as well as facilitators and supports for this approach must be acknowledged. In this article, we review various aspects of self‐management in chronic illness, focusing on chronic kidney disease. Better understanding of these concepts will facilitate patient–provider collaboration, improve patient care with increased patient and staff satisfaction, and may ultimately result in better clinical outcomes and enhanced quality of life for both the patients and their families.     

Economic impact of urinary stones

Kidney stones have been rising in prevalence in the United States and worldwide, and represent a significant cost burden. Cost effectiveness research in this area may enable improvements in treatment efficiency that can benefit patients, providers and the healthcare system. There has been limited research in the cost effectiveness of surgical interventions for stone disease, despite the diverse treatment approaches that are available. Medical expulsive therapy (MET) has been shown to improve rates of stone passage for ureteral stones, and there is evidence that this practice should be liberalized from the standpoint of both clinical and cost effectiveness. While conservative treatment following a primary stone event appears to be cost effective, the economic impact of medical therapy for recurrent stone formers requires clarification despite its clinical efficacy. Future study regarding the cost effectiveness of prevention and interventions for stone disease are likely to improve both the quality and efficiency of care.     

The incidence and clinical features of acute kidney injury secondary to ureteral calculi

The aim of this study is to evaluate the incidence and clinical features of acute kidney injury (AKI) secondary to ureteral calculi. Between February 2002 and December 2009, the prevalence of AKI was 0.72% in our series of 2,073 cases of ureteral stones. The AKI patients received ureteroscopy or percutaneous nephrostomy as the primary treatment. The most popular symptom was significant decrease in urine output (75%, 12/16). Five cases (33.3%) were caused by bilateral ureteral stones, and 76.19% of the stones were located in the upper ureter, the mean size of single stone was 1.35 ± 0.38 cm. The serum creatinine before treatment was 514.34 ± 267.04 μmol/L and the blood urea nitrogen before treatment was 21.31 ± 10.24 mmol/L. 46.67% of the patients had a functional or anatomical solitary kidney unit. Our study suggests that risk factors for developing AKI in ureteral stone patients are bigger sized stones, ureteral stones in patients with only one functioning kidney or pre-existing kidney disease, and bilateral ureteral stones. Early effective drainage in these cases could decrease the risk developing AKI secondary to ureteral calculi.     

Diagnosis and management of non-calcium-containing stones in the pediatric population

Compared to adults, urolithiasis is less common in children, with a definite rise in incidence, especially among young adults (Tasian et al. in Clin J Am Soc Nephrol 11:488, 2016). In the last 25 years, the incidence in children has increased by approximately 6–10% annually, for reasons still unknown, with an associated significant increase in related health care-related expenditures (Hyams and Matlaga in Transl Androl Urol 3(3):278–83, 2014). It has been shown that there is twice as high a risk of chronic kidney disease (CKD) or end stage renal disease (ESRD) in stone formers compared to non-stone formers (Tasian et al. 2016). While calcium-containing stones are by far the most common category of stone encountered in both children and adults, non-calcium stones are more common in children than adults and have been shown in several studies to be associated with greater morbidity and lower renal function than calcium stones (Issler et al. in BMC Nephrol 18(1):136, 2017; Gambaro et al. in J Urol 198:268–273, 2017). This could be related to the challenges in the management of non-calcium-containing stones due to associated infection or metabolic derangements, further leading to recurrence and loss of renal function. There is currently a gap in our understanding of how to appropriately and effectively encounter and manage patients with non-calcium-containing stones, as such cases are encountered less frequently. Identification of stone composition and appropriate management is very important to reduce serious complications and recurrence, especially in non-calcium stones. We present a review of diagnosis and management of non-calcium-containing stones in the pediatric population, in hopes of providing more clarity to providers and promoting a consideration of non-calcium stone composition with all children presenting with urolithiasis.     

Improving the Uptake of Independent Dialysis using the Humanbecoming Theoretical Approach

Soaring healthcare costs, increasing rates of chronic illness, and an aging population have left Canada struggling to meet the growing demands for quality health care. Hospitals battle to cope with altering patient demand, higher costs, provincially imposed global budgets, fast developing technology, rigid rules, new drugs, and social inequalities that lead to poor health. Canadian population health trends have played an important role in examining innovation opportunities that can dictate terms for the effective re‐design of Canada's health system. Independent (home) dialysis is associated with cost savings and improved quality of life in comparison with hospital‐based hemodialysis treatment. Despite this, independent dialysis has failed to increase at the same rate as hospital‐based treatment for chronic kidney disease. One probable reason is the lack of healthcare providers to truly understand the patient experience of living with chronic kidney disease. Qualitative data have shown that patients living with chronic kidney disease desire independence and minimal impact to their quality of life. Parse's Humanbecoming theory has been widely accepted in nursing practice as a theoretical base in which to gain an understanding of the lived experience. The values and assumptions of the Humanbecoming theory are also congruent with patient‐centered care practice and transferable to all areas of healthcare practice and disciplines.     

The risk of kidney stones following bariatric surgery: a systematic review and meta-analysis

Background With rising prevalence of morbid obesity, the number of bariatric surgeries performed each year has been increasing worldwide. The objective of this meta-analysis was to assess the risk of kidney stones following bariatric surgery. Methods A literature search was performed using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from inception through July 2015. Only studies reporting relative risks, odd ratios or hazard ratios (HRs) to compare risk of kidney stones in patients who underwent bariatric surgery versus no surgery were included. Pooled risk ratios (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method. Results Four studies (One randomized controlled trial and three cohort studies) with 11,348 patients were included in analysis to assess the risk of kidney stones following bariatric surgery. The pooled RR of kidney stones in patients undergoing bariatric surgery was 1.22 (95% CI, 0.63–2.35). The type of bariatric surgery subgroup analysis demonstrated an increased risk of kidney stones in patients following Roux-en-Y gastric bypass (RYGB) with the pooled RR of 1.73 (95% CI, 1.30–2.30) and a decreased risk of kidney stones in patients following restrictive procedures including laparoscopic banding or sleeve gastrectomy with the pooled RR of 0.37 (95% CI, 0.16–0.85). Conclusions Our meta-analysis demonstrates an association between RYGB and increased risk of kidney stones. Restrictive bariatric surgery, on the other hand, may decrease kidney stone risk. Future study with long-term follow-up data is needed to confirm this potential benefit of restrictive bariatric surgery.     

Management of urolithiasis with chronic renal failure

PURPOSE OF REVIEW: Epidemiological trends of urolithiasis and the prevalence of renal failure in patients with stones have changed. This is the era of minimally invasive therapy for stone disease. We review the impact of minimally invasive therapy on the management of urolithiasis in patients with renal failure and its outcome. RECENT FINDINGS: The prevalence of urolithiasis has reached its peak and plateaued in Europe and North America while it is still rising in the underdeveloped countries. The prevalence of renal failure in patients with chronic renal failure has reduced by half over the last decade. Minimally invasive therapy like percutaneous nephrolithotripsy has fared better than open stone surgery in all respects. Patients with kidney stones do not have normal renal function. Recently, cystine stones, and stones in patients with renal tubular acidosis and bowel disease were shown to affect renal function significantly. SUMMARY: Management of stones in chronic renal failure is challenging. Efforts should be made to minimize renal injury. Once a 'stone-free' kidney is achieved, steps should be taken to conserve renal function and address the issue of recurrence.     

Long term follow up of kidney donors with asymptomatic renal stones

Patients with asymptomatic kidney stones have a high rate of progression to becoming symptomatic kidney stones when followed for several years. Small kidney stones are often found incidentally on imaging when evaluating patients for kidney donation, and there is a concern that after nephrectomy, the donor may become symptomatic and incur damage to the remaining kidney. We reviewed kidney donors at our institution with asymptomatic stones and surveyed them several years after donation to see if the stones became clinically active.     

A close examination of healthcare expenditures related to fractures

This study evaluated reasons for healthcare expenditures both before and after the occurrence of fractures among Medicare beneficiaries. In a previous study we examined healthcare expenditures in the 6 months before and after fractures. The difference—“incremental” expenditures—provides one estimate of the potentially avoidable costs associated with fractures. We constructed a second estimate of the cost burden—“attributable” expenditures—using only those costs recorded in claims with fracture diagnosis codes. Attributable expenditures accounted for only 24% to 60% of incremental expenditures, depending on the fracture site. We examined health care expenditures between 1999 and 2005 among Medicare beneficiaries who experienced fractures (cases) and among beneficiaries who did not experience fractures (controls), matched to cases on age, race, and sex. We also examined healthcare expenditures for cases and controls for 24 months prior to the fracture index date. When expenditures associated with diagnoses for aftercare, joint pain, and osteoporosis, other musculoskeletal diagnoses, pneumonia, and pressure ulcers were included, the proportion of incremental costs directly attributable to fracture care rose to 72% to 88%. Expenditures prior to fracture were higher for cases than controls, and the rate of increase accelerated over the 12 months prior to the hip fracture. Our findings confirm that the original incremental cost analysis constituted a satisfactory method for estimating avoidable costs associated with fractures. We also conclude that those with fractures had much higher and growing healthcare expenditures in the 12 months prior to the event, compared with age‐, race‐, and sex‐matched controls. This suggests that patterns of healthcare services utilization may provide a means to improve fracture prediction rules. © 2013 American Society for Bone and Mineral Research.     

Evaluation of the kidney stone patient

Kidney stones are one of the most common chronic disorders in industrialized countries. In patients with kidney stones, the goal of medical therapy is to prevent the formation of new kidney stones and to reduce growth of existing stones. The evaluation of the patient with kidney stones should identify dietary, environmental, and genetic factors that contribute to stone risk. Radiologic studies are required to identify the stone burden at the time of the initial evaluation and to follow up the patient over time to monitor success of the treatment program. For patients with a single stone an abbreviated laboratory evaluation to identify systemic disorders usually is sufficient. For patients with multiple kidney stones 24-hour urine chemistries need to be measured to identify abnormalities that predispose to kidney stones, which guides dietary and pharmacologic therapy to prevent future stone events.     

Effects of extracorporeal shock-wave lithotripsy on intrarenal resistive index

OBJECTIVE: This prospective study was performed to determine whether extracorporeal shock-wave lithotripsy (ESWL), widely used for treating renal and ureteral stones, affects the kidney interlobar artery resistive index (RI). MATERIAL AND METHODS: A total of 43 patients (30 with renal and 13 with ureteral stones) underwent color Doppler examination before and 30 min and 3 h after ESWL. Seventeen patients with renal and nine with ureteral stones underwent Doppler examination 2 weeks later. Measurements were made near the stones (nearby region), at least 2 cm from the stones (remote region) and in the contralateral kidney for renal stones, and in the ipsilateral and contralateral kidneys for ureteral stones. RESULTS: In patients with renal stones, the RI was increased 30 min and 3 h after ESWL in the nearby and remote regions, and more markedly in the former. In the contralateral kidney, there was an increase in RI only at 3 h, which was less than that in the ipsilateral kidney. The RI at 2 weeks post-ESWL in the nearby region and contralateral kidney did not differ from the pre-ESWL values. ESWL performed for ureteral stones caused no increase in RI in the ipsilateral kidney. CONCLUSION: Patients with renal stones had a temporary increase in RI in the hours following ESWL in both the ipsilateral and contralateral kidneys, which was highest in the region near the stones and lowest in the contralateral kidney. Two weeks later, the RI in both areas had returned to pre-ESWL levels.     

Nanobacteria: an infectious cause for kidney stone formation

BACKGROUND: Nanobacteria are cytotoxic, sterile-filterable, gram-negative, atypical bacteria detected in bovine and human blood. Nanobacteria produce carbonate apatite on their cell walls. Data on Randall's plaques suggest that apatite may initiate kidney stone formation. We assessed nanobacteria in 72 consecutively collected kidney stones from Finnish patients. METHODS: Nanobacteria and kidney stone units were compared using scanning electron microscopy (SEM). Demineralized kidney stones were screened for nanobacteria using a double-staining method and a specific culture method. Isolated nanobacteria were analyzed for mineral formation in vitro with Ca and 85Sr incorporation tests. RESULTS: SEM highlighted the resemblance in size and morphology of nanobacteria and the smallest apatite units in the kidney stones. Nanobacterial antigens could be detected after the demineralization of the stones in 1 N HCl. Nanobacteria were surprisingly resistant to this treatment, and cultures could be established from 93.1% of the stones. Only struvite stones had common bacteria, in addition to the nanobacteria. When the results of all of the assays were combined, 70 of the 72 stones (that is, 97.2%) were nanobacteria positive. Although apatite stones indicated highest nanobacteria antigen signals, the overall nanobacteria positivity did not depend on the stone type. The isolated nanobacteria produced apatite stones in vitro, measured by Ca and 85Sr incorporation. CONCLUSIONS: We propose that kidney stone formation is a nanobacterial disease analogous to Helicobacter pylori infection and peptic ulcer disease. Both diseases are initiated by bacterial infection and subsequently endogenous and dietary factors influence their progression.     

Renal calculi in spinal cord-injured patient: association with reflux, bladder stones, and foley catheter drainage

Renal units associated with reflux in the spinal cord-injured (SCI) patient have a greater incidence of kidney stones developing than in the nonrefluxing units. It is logical to assume that SCI patients with persistent reflux and bladder stones treated with cystolitholapaxy would be at even higher risk for kidney stones developing. Of the 898 SCI patients studied (1,793 renal units), in 14.8 percent kidney stones developed. Kidney stones occurred in 161 of 1,517 (10.6%) of nonrefluxing units. Of the 276 renal units with reflux, in 104 (37.7%) an ipsilateral stone developed. Of the 198 patients in whom a kidney stone formed, 56.6 percent managed their bladder with a Foley catheter whereas only 28 percent of 700 patients in whom a stone did not form used a Foley catheter. On evaluating 261 patients (520 renal units) with bladder stones treated with cystolitholapaxy, 62.5 percent of these patients were managed with a Foley catheter. The association between cystolitholapaxy treatment, reflux, and the formation of kidney stones was (1) in 22 of 111 (19.8%) refluxing units, an ipsilateral stone formed; (2) in 70 of 409 (17.1%) units that were nonrefluxing, stones developed; and (3) overall, in 92 (17.7%) renal units, kidney stone developed. We concluded that kidney stone development is significantly increased in the SCI patient with reflux and/or Foley catheter drainage. From these data cystolitholapaxy treatment in the presence of reflux does not appear to increase the development of kidney stones.     

An analysis of stone management over the decade before the COVID-19 pandemic in Germany,France and England

Objectives

To understand the implications that the rising upper urinary tract (UUT) stone prevalence in Europe and the increasing burden places on patients and healthcare providers (HCPs), we investigated the evolution of diagnoses and procedures in Germany, France and England over the decade before the coronavirus disease 2019 (COVID-19) pandemic.

Methods

We identified International Classification of Diseases (ICD)-10 codes related to UUT stones diagnosis and extracted procedure volumes for extracorporeal shockwave lithotripsy (ESWL), ureteroscopy (URS), percutaneous nephrolithotomy and open surgery using national procedure codes from the German Institute for the Hospital Remuneration System, the French Technical Agency of Hospitalisation Information and NHS England Hospital Episode Statistics. We analysed procedures vs hospital diagnoses from 2010 to 2019 and reported results per 100 000 inhabitants.

Results

Between 2010 and 2019, ICD-10 N20 codes for calculus of kidney and ureter increased by 8%, 26% and 15% in Germany, France, and England respectively; whereas procedures increased by 3%, 38% and 18%. Of the patients diagnosed with stones, the percentage that received treatment (of any type) differed between countries. In 2019, in Germany 83% of patients diagnosed with stones received treatment, in France 88%, and in England 56%. These figures were relatively stable over the 10-year study period. Over the past decade, the dominant procedure shifted from ESWL to URS, and the average length of stay for URS decreased. Day case procedures increased in France and England (by 68% and 23%), no data were available in Germany.

Conclusion

This analysis highlights an increase in stone diagnoses and procedures, and a shift of surgical management. This development may be due to clinical advantages and advanced technology. The continued stone prevalence rise affects patients, hospitals, and HCPs.     

Spondyloarthropathy: an independent risk factor for kidney stones

PURPOSE: To better stratify risk and to verify previous prevalence reports, we conducted a retrospective cohort study comparing the lifetime incidence of nephrolithiasis in patients with spondyloarthropathies (SpA) and rheumatoid arthritis (RA). PATIENTS AND METHODS: Patients with SpA or rheumatoid factor-positive RA were identified from the rheumatology clinics of two Veterans Affairs hospitals and the University of Minnesota. Among them, 168 were confirmed to meet the American College of Rheumatology criteria and gave informed consent to participation. They were sent a survey regarding their rheumatologic diagnosis, coexistent conditions, medications, and history of kidney stones. Of the total, 143 patients responded and met the criteria for analysis. Rheumatoid arthritis patients were age and sex matched with SpA patients as controls. RESULTS: Populations were similar in all categories except that RA patients were more likely to have used prednisone (P < 0.001), bisphosphonates (P < 0.001), and calcium supplementation (P = 0.03). Kidney stones were reported by 23 (29.11%) of the 79 SpA patients compared with 8 (12.5%) of the 64 RA patients (chi (2) = 5.75; P = 0.025). Subgroup analysis of self-reporting stone history in 85 patients was found to be reliable on imaging review (sensitivity 82%; specificity 100%). CONCLUSIONS: Self-reporting of kidney stones by patients is a reliable measure. Despite adjusting for medication use and matching two similar arthritic populations, patients with SpA had a higher incidence of kidney stones than those with RA. This finding suggests that SpA is an independent risk factor for nephrolithiasis. Future studies will evaluate urinary risk factors and polymorphisms in the ANKH gene that may predispose to stone formation in this high-risk group.     

Evaluation of the results of extracorporeal shock-wave lithotripsy (ESWL) for solitary upper urinary tract stone

At Osaka City University Hospital, we performed extracorporeal shock-wave lithotripsy (ESWL) for 1277 patients in a total of 1788 sessions using Dornier kidney lithotripter Model HM III from July, 1985 to the end of December, 1988. Among the patients with a solitary stone, 911 cases were available for the follow-up study and we have compared the results among these cases in respect to the stone location and size. The results obtained were as follows: the ratio of kidney stone to ureter stone was found to be 2.2:1 in male, and 3.8:1 in female patients. This indicates that ureter stones are more frequently found in male than in female patients. In addition, we compared the size of kidney stones found in the patients including 415 male and 243 female patients. Stones larger than 20 mm were more frequently found in female than in male patients. Moreover, a stone composition study of these patients showed that the contents of both phosphate calcium and magnesium ammonium phosphate were higher in female than in male patients. ESWL performed against stones at pelvis and calyces exhibited the best results. The results obtained with the stones less than 20 mm in diameter were especially favorable with a success rate of 100% for the stones less than 10 mm and 83% for the stones 10-20 mm, in diameter, while the results with the stones larger than 20 mm in diameter were rather poor with a success rate of 31%. ESWL performed against ureter stones showed poor results with a success rate of 63% for the stones smaller than 20 mm in diameter.     

Fragmentation of care as a barrier to optimal ESKD management

Caring for patients with end-stage kidney disease (ESKD) in the United States is challenging, due in part to the complex epidemiology of the disease's progression as well as the ways in which care is delivered. As CKD progresses toward ESKD, the number of comorbidities increases and care involves multiple healthcare providers from multiple subspecialties. This occurs in the context of a fragmented US healthcare delivery system that is traditionally siloed by provider specialty, organization, as well as systems of payment and administration. This article describes the role of care fragmentation in the delivery of optimal ESKD care and identifies research gaps in the evidence across the continuum of care. We then consider the impact of care fragmentation on ESKD care from the patient and health system perspectives and explore opportunities for system-level interventions aimed at improving care for patients with ESKD.     

A retrospective claims analysis of the direct costs of stress urinary incontinence

The aim of this study was to evaluate direct expenditures associated with urinary incontinence and overall medical expenditures incurred by women diagnosed with stress urinary incontinence (SUI). The study design was a retrospective analysis of administrative claims data. We identified women with a diagnosis of SUI and no stress, urge or mixed urinary incontinence in the preceding 12 months using the MarketScan 1996–1999 databases. Total expenditures, as well as urinary incontinence-related expenditures, were summarized during the 12 months before and after the initial SUI diagnosis. We also compared expenditures for SUI patients receiving surgical treatment to expenditures for those who did not. There were 8126 patients who met the eligibility criteria. Total healthcare expenditures in the year prior to the initial SUI diagnosis were approximately half of those in the year following the initial diagnosis ($4478 vs $9147). For the subset of patients treated with surgery there was a threefold increase ($4575 vs $14129) in costs. A sensitivity analysis in patients with no comorbid urinary diagnoses found somewhat lower costs but a similar rate of increase in costs between the pre-period and the study period ($3884 vs $7075). Among women with no comorbid urinary diagnoses, approximately 11% ($769; SD $1180) of total mean regression-adjusted annual expenditures ($6892; SD $5067) was attributable to UI. Predicted total expenditures for surgery patients without comorbid urinary diagnoses were $13 212 (SD $7967), 28% of which ($3640;SD $681) were for UI-related costs. We concluded that after diagnosis, annual expenditures for patients were roughly twice those in the year prior to diagnosis. Multivariate analysis suggests that in the year after SUI diagnosis, UI treatment costs represented approximately 10% of total expenditures for all SUI patients, and 26%–28% of total expenditures for the subset of surgically treated patients.Abbreviations SUI Stress urinary incontinence - UI Urinary incontinence Editorial Comment: This paper addresses the costs related specifically to a new diagnosis of stress incontinence. The authors take a different approach from that of other cost studies, in that they exclude women with pre-existing diagnoses of incontinence, focus just on stress incontinence, and provide specific data about each compartment of direct cost. One strength of the design is its longitudinal follow-up by clearly identifying a population of women newly diagnosed with SUI and looking at the costs incurred for at least the following 12 months. A potential limitation is the instability of the population. More studies analyzing direct and indirect costs associated with incontinence are needed.     

Acoustic and mechanical properties of artificial stones in comparison to natural kidney stones

PURPOSE: Standardized and reproducible artificial kidney stone models are important for performing comparative studies of different lithotripsy modalities. The acoustic and mechanical properties of renal calculi dictate the manner by which stones interact with the mechanical stresses produced by shock wave lithotripsy (SWL) or intracorporeal lithotripsy modalities. We have developed a novel artificial kidney stone model that is made of natural substances found in real kidney stones. These stone models appear to be much closer in physical properties to natural kidney stones than previously used stone models. MATERIALS AND METHODS: The acoustic and mechanical properties of six groups of artificial stone models were compared to corresponding natural stones of similar compositions. Moreover, three groups of artificial stone models made of plaster-of-Paris were compared to their natural counterparts. In terms of acoustic properties, stone density was measured using a pycnometer based on Archimedes' principle, whereas longitudinal and transverse (or shear) wave propagation speeds were measured using an ultrasound pulse transmission technique. These values were used to calculate wave impedance and dynamic mechanical properties (bulk modulus, Young's modulus, and shear modulus) of the stones. The microhardness of the stones was measured and the effect of composition on stone fragility was evaluated. RESULTS: Artificial stones, when compared to natural stones of similar composition, showed similar trends in longitudinal and transverse wave speeds, wave impedance, and dynamic elastic moduli. However, values for the artificial stones were uniformly low compared to those of natural stones, suggesting that these artificial stones may be more amenable to shock wave fragmentation. The results of SWL on stone fragmentation of artificial and natural stones also revealed similar trends with the exception of artificial cystine stones which were found to be the most resistant to shock wave fragmentation. CONCLUSIONS: The results indicate that the physical properties of artificial stones made of natural stone materials are comparable to renal calculi of the same chemical composition. The data suggests that these stone phantoms are suitable for performing standardized and reproducible in vitro investigations, especially with regards to fragility of kidney stones of different chemical compositions during SWL.     

Protein components of amyloid-like kidney stones of chronic hemodialysis patients

We have examined amyloid-like kidney stones, commonly found in patients on maintenance hemodialysis. Extraction of protein from the stones and Western blot analysis were performed. beta 2-Microglobulin (beta 2MG), serum amyloid P component (SAP), lysozyme and PAS-positive substance were identified in the stones. It is suggested that calcium-mediated association of beta 2MG, lysozyme, SAP and PAS-positive substance may have an important role in the process of the formation of kidney stones in chronic hemodialysis patients.