Tania Schianchi

Urine Volume: Stone Risk Factor and Preventive Measure

Background: A high fluid intake is the oldest existing treatment for kidney stones, and, up until a few decades ago, it was the only preventive measure at the physician’s disposal for stone recurrences. Methods: Using the data available in literature and partly unpublished personal research, we examine the role of urine volume as a stone risk factor, its impact on calcium crystallization mechanisms and its real importance as a means of prevention. Results: To sum up, the most important findings are: (1) a low urine volume must be considered as a real risk factor, both as regards the onset of renal calculi and stone relapses; (2) an increase in urine volume induced by a high water intake produces favourable effects on the crystallization of calcium oxalate and does not reduce the activity of natural inhibitors; (3) a sufficiently high intake of water and probably other fluids such as coffee, tea, beer and wine has a preventive effect on nephrolithiasis and its recurrence, and (4) the role of fruit juice is still to be defined. Conclusions: A high intake of fluids, especially water, is still the most powerful and certainly the most economical means of prevention of nephrolithiasis, and it is often not used to advantage by stone formers.

Body Weight, Diet and Water Intake in Preventing Stone Disease

Nutrition plays a major role in the pathogenesis of the most widespread forms of nephrolithiasis, i.e. calcium (calcium oxalate and phosphate) and uric acid stone disease. For this reason, dietary measures are the first level of intervention in primary prevention, as well as in secondary prevention of recurrences. An unbalanced diet or particular sensitivity to various foods in stone formers can lead to urinary alterations such as hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia and an excessively acid urinary pH. Over the course of time, these conditions contribute to the formation or recurrence of kidney stones, due to the effect they exert on the lithogenous salt profile. The fundamental aspects of the nutritional approach to the treatment of idiopathic nephrolithiasis are body weight, diet and water intake. This paper will present data resulting from our own investigations and the most significant evidence in literature.

Reducing unnecessary hospital days to improve quality of care through physician accountability: a cluster randomised trial

BackgroundOver 20% of hospital bed use is inappropriate, implying a waste of resources and the increase of patient iatrogenic risk.MethodsThis is a cluster, pragmatic, randomised controlled trial, carried out in a large University Hospital of Northern Italy, aiming to evaluate the effect of a strategy to reduce unnecessary hospital days. The primary outcome was the percentage of patient-days compatible with discharge. Among secondary objectives, to describe the strategy’s effect in the long-term, as well as on hospital readmissions, considered to be a marker of the quality of hospital care. The 12 medical wards with the longest length of stay participated. Effectiveness was measured at the individual level on 3498 eligible patients during monthly index days. Patients admitted or discharged on index days, or with stay >90 days, were excluded. All ward staff was blinded to the index days, while staff in the control arm and data analysts were blinded to the trial’s objectives and interventions. The strategy comprised the distribution to physicians of the list of their patients whose hospital stay was compatible with discharge according to a validated Delay Tool, and of physician length of stay profiles, followed by audits managed autonomously by the physicians of the ward.ResultsDuring the 12 months of data collection, over 50% of patient-days were judged to be compatible with discharge. Delays were mainly due to problems with activities under medical staff control. Multivariate analysis considering clustering showed that the strategy reduced patient-days compatible with discharge by 16% in the intervention vs control group, (OR=0.841; 95% CI, 0.735 to 0.963; P=0.012). Follow-up at 1 year did not yield a statistically significant difference between the percentages of patient-days judged to be compatible with discharge between the two arms (OR=0.818; 95% CI, 0.476 to 1.405; P=0.47). There was no significant difference in 30-day readmission and mortality rates for all eligible patients (N=3498) between the two arms.ConclusionsResults indicate that a strategy, involving physician direct accountability, can reduce unnecessary hospital days. Relatively simple interventions, like the one assessed in this study, should be implemented in all hospitals with excessive lengths of stay, since unnecessary prolongation may be harmful to patients.Trial registrationClinicalTrials.gov, identifier NCT01422811.

Medical treatment of nephrolithiasis

The medical treatment of nephrolithiasis is aimed in particular at the prevention of relapses, even though in some cases, such as cystine or uric acid lithiasis, the calculi also can be dissolved on site. When the diagnosis and metabolic profile have been performed correctly, medical treatment is effective in a large number of patients. The greatest difficulty is the patients compliance with the most suitable prevention measures and the frequency of follow-up controls. This compliance can be influenced significantly by the amount of time that the doctor spends to explain the origin of the disease. This article reviews the main methods available for the medical treatment of various nephrolithiasis types, namely water intake, diet, and drugs, supplying the relevant information about the mechanism of action, metabolic consequences, indications, evidence provided from studies, dosage, efficacy, and side-effects. Finally, brief simplified guidelines are given for the medical treatment of stone disease caused by calcium oxalate or calcium phosphate, uric acid, cystine, and struvite.

Calcium oxalate crystallization in untreated urine, centrifuged and filtered urine and ultrafiltered urine.

Abstract Centrifuged and filtered urine is often used to evaluate in vitro the crystallization processes of calcium oxalate (CaOx), but even such simple manipulations can alter the composition of the urine, as regards its protein and lipid concentrations. In urine samples taken from 17 normal male adults, we evaluated CaOx crystallization by simultaneously using three different types of urine: untreated (U), centrifuged at 2000 rpm (800 g)and filtered at 0.22 μm (CF), and centrifuged-filtered and ultrafiltered at 10 000 Da (CFU). The addition of 1.2 mmol/l of oxalate to each type of urine produced notably different results. The total amount of CaOx crystals (expressed as calcium oxalate dihydrate crystals (COD)+oxalate monohydrate crystals (COM)area/total area × 100)was on average 13.2% in U urine, 70.7% in CF urine and 11.1% in CFU urine (CF>U and CFU, U=CFU); the relative prevalence of COD and COM (expressed as COD area/COM area) was on average 71.4 in U urine, 0.0026 in CF urine and 5.5 in CFU urine (U>CF and CFU, CFU>CF); the diameter of COD (expressed in microns)was on average 15.2 in U urine, 3.7 in CF urine and 24.3 in CFU urine (CFU>U and CF, U>CF); the diameter of COM (expressed in microns)was on average 5.2 in U urine, 2.6 in CF urine and 8.9 in CFU urine (CFU>U and CF, U>CF); the total amount of CaOx aggregates (expressed as CaOxAgg area/total area×100)was on average 8.5% in U urine, 22.1% in CF urine and 2.9% in CFU urine (CF>U and CFU, U>CF). We conclude that CaOx crystallization processes in manipulated urine are extremely different, probably due to changes in macromolecular compounds.