Water for preventing urinary calculi

Water for preventing urinary stones

BACKGROUND

Urinary stone disease is a common condition characterised by increasing prevalence and high rates of recurrence. Observational studies have reported that increased water intake played a role in the prevention of urinary stone formation but with limited strength of evidence.

OBJECTIVES

To compare the effects of increased water intake with standard water intake for the prevention of urinary stone formation in participants with or without a history of urinary stones.

SEARCH METHODS

We performed a systematic search of PubMed (MEDLINE), EMBASE (Ovid) and the Cochrane Library to 15 October 2019. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles. We did not apply any restrictions to publication language or publication status.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs looking at the benefits and harms of increased water intake versus standard water intake for the prevention of urinary stone formation in participants with or without a history of urinary stones.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently extracted data and assessed the risk of bias of included studies. We pooled dichotomous outcomes (e.g. incidence/recurrence rate of urinary stones; adverse events) using risk ratios (RRs) with 95% confidence intervals (CIs). We calculated hazard ratio (HRs) and corresponding 95% CIs to assess the intervention effect for time-to-event outcomes. We assessed the certainty of the evidence by using the GRADE criteria.

MAIN RESULTS

Our search identified no RCTs investigating the role of increased water intake for the prevention of urinary stone formation in participants with no history of urinary stones (primary prevention). We found one RCT assessing the effects of increased water intake versus standard water intake for the prevention of urinary stone formation in people with a history of urinary stones (secondary prevention). This trial randomised 220 participants (110 participants in the intervention group with increased water intake and 110 in the control group with standard water intake). Increased water intake was defined as achieving a urine volume of at least 2.0 L per day by drinking water. Based on this study, increased water intake may decrease stone recurrences (RR 0.45, 95% CI 0.24 to 0.84; 199 participants; low-certainty evidence); this corresponds to 149 fewer (43 fewer to 205 fewer) stone recurrences per 1000 participants with 270 stone recurrence per 1000 participants over five years in the control group. Increased water intake may also prolong the time to urinary stone recurrence compared to standard water intake (HR 0.40, 95% CI 0.20 to 0.79; 199 participants; low-certainty evidence); based on a stone recurrence rate of 270 per 1000 participants over five years, this corresponds to 152 fewer (209 fewer to 50 fewer) recurrences per 1000 participants. For both outcomes we downgraded the certainty of evidence for study limitations and imprecision. We found no evidence for the outcome of adverse events AUTHORS' CONCLUSIONS: We found no RCT evidence on the role of increased water intake for primary prevention of urinary stones. For secondary prevention, increased water intake achieving a urine volume of at least 2.0 L/day may reduce urinary stone recurrence and prolong time to recurrence for people with a history of urinary stone disease. However, our confidence in these findings is limited. We did not find evidence for adverse events.

Dietary interventions for preventing complications in idiopathic hypercalciuria

BACKGROUND

Idiopathic hypercalciuria is an inherited metabolic abnormality that is characterised by excessive amounts of calcium excreted in the urine by people whose calcium serum levels are normal. Morbidity associated with idiopathic hypercalciuria is chiefly related to kidney stone disease and bone demineralisation leading to osteopenia and osteoporosis. Idiopathic hypercalciuria contributes to kidney stone disease at all life stages; people with the condition are prone to developing oxalate and calcium phosphate kidney stones. In some cases, crystallised calcium can be deposited in the renal interstitium, causing increased calcium levels in the kidneys. In children, idiopathic hypercalciuria can cause a range of comorbidities including recurrent macroscopic or microscopic haematuria, frequency dysuria syndrome, urinary tract infections and abdominal and lumbar pain. Various dietary interventions have been described that aim to decrease urinary calcium levels or urinary crystallisation.

OBJECTIVES

Our objectives were to assess the efficacy, effectiveness and safety of dietary interventions for preventing complications in idiopathic hypercalciuria (urolithiasis and osteopenia) in adults and children, and to assess the benefits of dietary interventions in decreasing urological symptomatology in children with idiopathic hypercalciuria.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register (23 April 2013) through contact with the Trials' Search Co-ordinator using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE and EMBASE.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs that investigated dietary interventions aimed at preventing complications of idiopathic hypercalciuria, compared with placebo, no intervention, or other dietary interventions regardless of route of administration, dose or amount.

DATA COLLECTION AND ANALYSIS

Studies were assessed for inclusion and data extracted using a standardised data extraction form. We calculated risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, both with 95% confidence intervals (CI).

MAIN RESULTS

We included five studies (379 adult participants) that investigated a range of interventions. Lack of similarity among interventions investigated meant that data could not be pooled. Overall, study methodology was not adequately reported in any of the included studies. There was a high risk of bias associated with blinding (although it seems unlikely that outcomes measures were unduly influenced by lack of intervention blinding), random sequence generation and allocation methodologies were unclear in most studies, but selective reporting bias was assessed as low.One study (120 participants) compared a low calcium diet with a normal calcium, low protein, low salt diet for five years. There was a significant decrease in numbers of new stone recurrences in those treated with the normal calcium, low protein, low salt diet (RR 0.77, 95% CI 0.61 to 0.98). This diet also led to a significant decrease in oxaluria (MD 78.00 µmol/d, 95% CI 26.48 to 129.52) and the calcium oxalate relative supersaturation index (MD 1.20 95% CI 0.21 to 2.19).One study (210 participants) compared a low salt, normal calcium diet with a broad diet for three months. The low salt, normal calcium diet decreased urinary calcium (MD -45.00 mg/d, 95% CI -74.83 to -15.17) and oxalate excretion (MD -4.00 mg/d, 95% CI -6.44 to -1.56).A small study (17 participants) compared the effect of dietary fibre as part of a low calcium, low oxalate diet over three weeks, and found that although calciuria levels decreased, oxaluria increased. Phyllanthus niruri plant substrate intake was investigated in a small subgroup with hypercalciuria (20 participants); there was no significant effect on calciuria levels occurred after three months of treatment.A small cross-over study (12 participants) evaluating the changes in urinary supersaturation indices among patients who consumed calcium-fortified orange juice or milk for one month found no benefits for participants.None of the studies reported any significant adverse effects associated with the interventions.

AUTHORS' CONCLUSIONS

Long-term adherence (five years) to diets that feature normal levels of calcium, low protein and low salt may reduce numbers of stone recurrences, decrease oxaluria and calcium oxalate relative supersaturation indexes in people with idiopathic hypercalciuria who experience recurrent kidney stones. Adherence to a low salt, normal calcium level diet for some months can reduce calciuria and oxaluria. However, the other dietary interventions examined did not demonstrate evidence of significant beneficial effects.No studies were found investigating the effect of dietary recommendations on other clinical complications or asymptomatic idiopathic hypercalciuria.

Prevalence of kidney stones in the United States

BACKGROUND

The last nationally representative assessment of kidney stone prevalence in the United States occurred in 1994. After a 13-yr hiatus, the National Health and Nutrition Examination Survey (NHANES) reinitiated data collection regarding kidney stone history.

OBJECTIVE

Describe the current prevalence of stone disease in the United States, and identify factors associated with a history of kidney stones.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional analysis of responses to the 2007-2010 NHANES (n=12 110).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Self-reported history of kidney stones. Percent prevalence was calculated and multivariable models were used to identify factors associated with a history of kidney stones.

RESULTS AND LIMITATIONS

The prevalence of kidney stones was 8.8% (95% confidence interval [CI], 8.1-9.5). Among men, the prevalence of stones was 10.6% (95% CI, 9.4-11.9), compared with 7.1% (95% CI, 6.4-7.8) among women. Kidney stones were more common among obese than normal-weight individuals (11.2% [95% CI, 10.0-12.3] compared with 6.1% [95% CI, 4.8-7.4], respectively; p<0.001). Black, non-Hispanic and Hispanic individuals were less likely to report a history of stone disease than were white, non-Hispanic individuals (black, non-Hispanic: odds ratio [OR]: 0.37 [95% CI, 0.28-0.49], p<0.001; Hispanic: OR: 0.60 [95% CI, 0.49-0.73], p<0.001). Obesity and diabetes were strongly associated with a history of kidney stones in multivariable models. The cross-sectional survey design limits causal inference regarding potential risk factors for kidney stones.

CONCLUSIONS

Kidney stones affect approximately 1 in 11 people in the United States. These data represent a marked increase in stone disease compared with the NHANES III cohort, particularly in black, non-Hispanic and Hispanic individuals. Diet and lifestyle factors likely play an important role in the changing epidemiology of kidney stones.

Water for preventing urinary stones

BACKGROUND

Urinary stones are a common condition characterised by high incidence and high recurrence rate. For a long time, increased water intake has been the main preventive measure for the disease and its recurrence. This is an update of a review originally published in 2004.

OBJECTIVES

To assess the effectiveness of increased water intake for the primary and secondary prevention of urinary stones.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register, CENTRAL, MEDLINE, EMBASE, and the Chinese Biomedical Disk using a search strategy developed in conjunction with Cochrane Renal Group's Trials Search Co-ordinator. No language restriction was applied. Date of last search: April 2012.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of increased water intake for the prevention of urinary stones and its recurrence were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

No studies of increased water intake for the primary prevention of urinary stones met the inclusion criteria. One study with 199 patients provided results of increased water intake for the recurrence of urinary stones. The stone recurrence was lower in the increased water intake group than that of the no intervention group (12% versus 27%; RR 0.45, 95% CI 0.24 to 0.84). The average interval for recurrence was 3.23 ± 1.1 years in increased water intake group and 2.09 ± 1.37 years in the no intervention group (MD 1.14, 95% CI 0.33 to 1.95). There were insufficient data to assess selection, performance, detection or attrition bias.

AUTHORS' CONCLUSIONS

The evidence from only one study indicates that increased water intake reduces the risk of recurrence of urinary stones and prolongs the average interval for recurrences. However further research is required. Due to the lack of appropriate RCTs, no conclusions can be drawn on increased water intake for the primary and secondary prevention of urinary stones.

Studies on the in vitro and in vivo antiurolithic activity of Holarrhena antidysenterica

Holarrhena antidysenterica has a traditional use in the treatment of urolithiasis, therefore, its crude extract has been investigated for possible antiurolithic effect. The crude aqueous-methanolic extract of Holarrhena antidysenterica (Ha.Cr) was studied using the in vitro and in vivo methods. In the in vitro experiments, Ha.Cr demonstrated a concentration-dependent (0.25-4 mg/ml) inhibitory effect on the slope of aggregation. It decreased the size of crystals and transformed the calcium oxalate monohydrate (COM) to calcium oxalate dehydrate (COD) crystals, in calcium oxalate metastable solutions. It also showed concentration-dependent antioxidant effect against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and lipid peroxidation induced in rat kidney tissue homogenate. Ha.Cr (0.3 mg/ml) reduced (p < 0.05) the cell toxicity and LDH release in renal epithelial cells (MDCK) exposed to oxalate (0.5 mM) and COM (66 μg/cm(2)) crystals. In male Wistar rats, receiving 0.75 % ethylene glycol (EG) for 21 days along with 1 % ammonium chloride (AC) in drinking water, Ha.Cr treatment (30-100 mg/kg) prevented the toxic changes caused by lithogenic agents; EG and AC, like loss of body weight, polyurea, oxaluria, raised serum urea and creatinine levels and crystal deposition in kidneys compared to their respective controls. These data indicate that Holarrhena antidysenterica possesses antiurolithic activity, possibly mediated through the inhibition of CaOx crystal aggregation, antioxidant and renal epithelial cell protective activities and may provide base for designing future studies to establish its efficacy and safety for clinical use.

Fluids and diuretics for acute ureteric colic

BACKGROUND

Acute ureteric colic is commonly associated with severe and debilitating pain. Theoretically, increasing fluid flow through the affected kidney might expedite stone passage, thereby improving symptoms more quickly. The efficacy and safety of interventions such as high volume intravenous (IV) or oral fluids and diuretics aimed at expediting ureteric stone passage is, however, uncertain.

OBJECTIVES

To look at the benefits and harms of diuretics and high volume (above maintenance) IV or oral fluid therapy for treating adult patients presenting with uncomplicated acute ureteric colic.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register (3 January 2012). Previously we searched the Cochrane Central Register of Controlled Trials (CENTRAL The Cochrane Library), MEDLINE (from 1966), EMBASE (from 1980) and handsearched reference lists of nephrology and urology textbooks, review articles, relevant studies, and abstracts from nephrology scientific meetings.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs (including the first period of randomised cross-over studies) looking at diuretics or high volume IV or oral fluids for treating uncomplicated acute ureteric colic in adult patients presenting to the emergency department for the first time during that episode were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random-effects model for multiple studies of the same outcomes, otherwise the fixed-effect model was used. Results were expressed as risk ratios (RR) for dichotomous outcomes or as mean differences (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Two studies (enrolling 118 participants) examined the association between intense hydration and ureteric colic outcomes. There was no significant difference in pain at six hours (1 study, 60 participants: RR 1.06, 95% CI 0.71 to 1.57), surgical stone removal (1 study, 60 participants: RR 1.20, 95% CI 0.41 to 3.51) or manipulation by cystoscopy (1 study, 60 participants: RR 0.67, 95% CI 0.21 to 2.13) when no fluids over six hours was compared to three litres IV fluids administered over a six hour period. There was no difference in stone clearance (1 study 43 participants: RR 1.38, 95% CI 0.50 to 3.84), hourly pain score or patients' narcotic requirements (P > 0.05 for all comparisons) when forced IV hydration of two litres over four hours was compared with minimal IV hydration at 20 mL/hour.One study did not provide any details which would have allowed us to assess any of the risk of bias items (selection, detection, performance, attrition or reporting bias). The second study did not report the method of randomisation or allocation (selection bias - unclear), they reported that the patients were blinded to therapy (low risk of bias), analgesics were administered according to predetermined pain score criteria (low risk), and assessment of stone passage was unlikely to have been biased by knowledge of group assignment (low risk). However the second study also reported a high percentage of participants excluded post randomisation (26%; high risk of bias). We were unable to assess or ascertain any of the other risk of bias items.

AUTHORS' CONCLUSIONS

We found no reliable evidence in the literature to support the use of diuretics and high volume fluid therapy for people with acute ureteric colic. However, given the potential positive therapeutic impact of fluids and diuretics to facilitate stone passage, the capacity of these interventions warrants further investigation to determine safety and efficacy profiles.

Diet, fluid, or supplements for secondary prevention of nephrolithiasis: a systematic review and meta-analysis of randomized trials

CONTEXT

Although numerous trials have evaluated efficacy of diet, fluid, or supplement interventions for secondary prevention of nephrolithiasis, few are included in previous systematic reviews or referenced in recent nephrolithiasis management guidelines.

OBJECTIVE

To determine efficacy and safety of diet, fluid, or supplement interventions for secondary prevention of nephrolithiasis.

EVIDENCE ACQUISITION

Systematic review and meta-analysis of trials published January 1950 to March 2008. Sources included Medline and bibliographies of retrieved articles. Eligible trials included adults with a history of nephrolithiasis; compared diet, fluids, or supplements with control; compared relevant outcomes between randomized groups (eg, stone recurrence); had > or = 3 mo follow-up; and were published in the English language. Data were extracted on participant and trial characteristics, including study methodologic quality.

EVIDENCE SYNTHESIS

Eight trials were eligible (n=1855 participants). Study quality was mixed. In two trials, water intake > 2 l/d or fluids to achieve urine output > 2.5 l/d reduced stone recurrence (relative risk: 0.39; 95% confidence interval: 0.19-0.80). In one trial, fewer high soft drink consumers assigned to reduced soft drink intake had renal colic than controls (34% vs 41%, p=0.023). Content and results of multicomponent dietary interventions were heterogeneous; in one trial, fewer participants assigned increased dietary calcium, low animal protein, and low sodium had stone recurrence versus controls (20% vs 38%, p=0.03), while in another trial, more participants assigned diets that included low animal protein, high fruit and fiber, and low purine had recurrent stones than controls (30% vs 4%, p=0.004). No trials examined the independent effect of altering dietary calcium, sodium, animal protein, fruit and fiber, purine, oxalate, or potassium. Two trials showed no benefit of supplements over control treatment. Adverse event reporting was poor.

CONCLUSIONS

High fluid intake decreased risk of recurrent nephrolithiasis. Reduced soft drink intake lowered risk in patients with high baseline soft drink consumption. Data for other dietary interventions were inconclusive, although limited data suggest possible benefit from dietary calcium.