Effect of Indapamide on Urinary Calcium Excretion in Patients with and without Urinary Stone Disease

Urinary supersaturation in a Randomized trial among Individuals with Nephrolithiasis comparing Empiric versus selective therapy (URINE): design and rationale of a clinical trial

Clinical guidelines disagree on whether the identification of abnormal urine chemistries should occur before starting diet and medication interventions to prevent the recurrence of kidney stone events. We describe the rationale and design of the Urinary supersaturation in a Randomized trial among Individuals with Nephrolithiasis comparing Empiric versus selective therapy (URINE) study, a randomized trial comparing two multi-component interventions to improve urinary supersaturation. Participants are randomized (1:1 ratio) to the empiric or selective arm. The target sample size is 56 participants. Adults ≥ 18 years of age with idiopathic calcium stone disease and two symptomatic stone events within the previous 5 years. Exclusion criteria include systemic conditions predisposing to kidney stones and pharmacologic treatment for stone prevention at baseline. Participants in the empiric arm receive standard diet therapy recommendations, thiazide, and potassium citrate. Participants in the selective arm receive tailored diet and nutrient recommendations and medications based on baseline and 1-month follow-up of 24-h urine testing results. The primary endpoints are urinary supersaturations of calcium oxalate and calcium phosphate at 2 months of follow-up. Secondary endpoints include side effects, diet and medication adherence, and changes in 24-h urine volume, calcium, oxalate, citrate, and pH. Short-term changes in urinary supersaturation may not reflect changes in future risk of stone events. The URINE study will provide foundational data to compare the effectiveness of two prevention strategies for kidney stone disease.

Risks associated with drug treatments for kidney stones

INTRODUCTION

Renal stones are one of the most painful medical conditions patients experience. For many they are also a recurrent problem. Fortunately, there are a number of drug therapies available to treat symptoms as well as prevent future stone formation.

AREAS COVERED

Herein, we review the most common drugs used in the treatment of renal stones, explaining the mechanism of action and potential side effects. Search of the Medline databases and relevant textbooks was conducted to obtain the relevant information. Further details were sourced from drug prescribing manuals. Recent studies of drug effectiveness are included as appropriate.

EXPERT OPINION

Recent controversies include medical expulsive therapy trials and complex role of urinary citrate in stone disease. Future directions in research will involve new medical therapies for stone prevention, for example new drugs for hyperoxaluria.

Intensive blood pressure control, falls, and fractures in patients with type 2 diabetes: the ACCORD trial

BACKGROUND

There are few rigorous studies to confirm or refute the commonly cited concern that control of blood pressure to lower thresholds may result in an increased risk of falls and fractures.

OBJECTIVE

To compare falls and fractures in participants with type 2 diabetes in the intensive (targeting a systolic blood pressure of < 120 mmHg) and standard (targeting a systolic blood pressure of < 140 mmHg) blood pressure control arms of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) randomized trial (N = 4,733).

PARTICIPANTS

A subset of 3,099 participants self-reported annually on the occurrence of falls and non-spine fractures. Fractures were centrally adjudicated.

MAIN MEASURES

The incidence of falls in the two treatment groups was compared using a random-effects negative binomial model, and fracture risk was compared using Cox proportional hazards models.

KEY RESULTS

At enrollment in both groups, the mean age was 62 years, 44% were women, 25% were Black, and mean blood pressure was 138/75 mmHg. During follow-up, all classes of medications, particularly thiazide diuretics, were more commonly prescribed in the intensive group. After 1 year of follow-up, the mean systolic blood pressure was 133 ± 15 mmHg in the standard group and 119 ± 14 mmHg in the intensive group. The adjusted rate of falls did not differ in the intensive and standard groups (62.2/100 person-years vs. 74.1/100 person-years, RR = 0.84, 95% CI 0.54-1.29, p = 0.43). The risk of non-spine fractures was nonsignificantly lower in the intensive than in the standard blood pressure group (HR 0.79, 95% CI 0.62-1.01, p = 0.06).

CONCLUSIONS

We conclude that intensive antihypertensive treatment that lowered mean systolic blood pressure to below 120 mmHg was not associated with an increased risk of falls or non-spine fractures in patients age 40 to 79 years with type 2 diabetes.

Role of proximal tubule in the hypocalciuric response to thiazide of patients with idiopathic hypercalciuria

The most common metabolic abnormality found in calcium (Ca) kidney stone formers is idiopathic hypercalciuria (IH). Using endogenous lithium (Li) clearance, we previously showed that in IH, there is decreased proximal tubule sodium absorption, and increased delivery of Ca into the distal nephron. Distal Ca reabsorption may facilitate the formation of Randall's plaque (RP) by washdown of excess Ca through the vasa recta toward the papillary tip. Elevated Ca excretion leads to increased urinary supersaturation (SS) with respect to calcium oxalate (CaOx) and calcium phosphate (CaP), providing the driving force for stone growth on RP. Thiazide (TZ) diuretics reduce Ca excretion and prevent stone recurrence, but the mechanism in humans is unknown. We studied the effect of chronic TZ administration on renal mineral handling in four male IH patients using a fixed three meal day in the General Clinical Research Center. Each subject was studied twice: once before treatment and once after 4-7 mo of daily chlorthalidone treatment. As expected, urine Ca fell with TZ, along with fraction of filtered Ca excreted. Fraction of filtered Li excreted also fell sharply with TZ, as did distal delivery of Ca. Unexpectedly, TZ lowered urine pH. Together with reduced urine Ca, this led to a marked fall in CaP SS, but not CaOx SS. Since CaOx stone formation begins with an initial CaP overlay on RP, by lowering urine pH and decreasing distal nephron Ca delivery, TZ might diminish stone risk both by reducing CaP SS, as well as slowing progression of RP.

Bisphosphonates in the management of idiopathic hypercalciuria associated with osteoporosis: a new trick from an old drug

Idiopathic hypercalciuria (IHC) is defined as a 24-hour urinary calcium excretion that exceeds 4 mg/kg/day, regardless of gender and in absence of systemic diseases or pharmacological treatments that may cause normocalcemic hypercalciuria (eg sarcoidosis, normocalcemic primary hyperparathyroidism, vitamin D intoxication, hyperthyroidism). Patients with IHC and nephrolithiasis often present increased bone turnover, decreased bone mineral density (BMD) and increased susceptibility to fragility fractures. Although the pathogenesis of IHC seems complex and multifactorial, recent evidences suggest that cells involved in bone resorption may play a critical role in the chain of events leading to the excessive urinary calcium excretion. Therefore, it has been proposed that bisphosphonates, potent inhibitors of bone resorption, may have beneficial effects in hypercalciuric patients with low BMD. This manuscript reports recent findings regarding the role of bone tissue in the pathogenesis of IHC, and supports the use of bisphosphonates in such conditions. It also reviews the literature on the effects of bisphosphonates in subjects with osteoporosis-associated IHC.

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.

The effect of treatment based on a diuretic (indapamide) +/- ACE inhibitor (perindopril) on fractures in the Hypertension in the Very Elderly Trial (HYVET)

BACKGROUND

fractures may have serious implications in an elderly individual, and fracture prevention may include a careful choice of medications.

DESIGN

the Hypertension in the Very Elderly Trial (HYVET) was a double-blind placebo-controlled trial of a thiazide-like diuretic (indapamide 1.5 mg SR) with the optional addition of the angiotensin-converting enzyme (ACE) inhibitor (perindopril 2-4 mg). Fracture was a secondary end point of the trial.

SETTING

HYVET recruited participants from Eastern and Western Europe, China, Australasia, and Tunisia.

SUBJECTS

all participants were > or =80 years of age and hypertensive.

METHODS

participants were randomised to receive a thiazide-like diuretic (indapamide 1.5 mg SR) +/- ACE inhibitor (perindopril 2-4 mg) or matching placebos. Incident fractures were validated and analysed based on time to first fracture.

RESULTS

there were 3,845 participants in HYVET and a total 102 reported fractures (42 in the active and 60 in the placebo group). When taking only validated first fractures, 90 were included in the analyses (38 in the active and 52 in the placebo group). Cox proportional hazard regression, adjusted for key baseline risk factors, resulted in a point estimate of 0.58 (95% CI 0.33-1.00, P = 0.0498).

CONCLUSIONS

despite the lowering of blood pressure, treatment with a thiazide-like diuretic and an ACE inhibitor does not increase and may decrease fracture rate.

Alendronate and indapamide alone or in combination in the management of hypercalciuria associated with osteoporosis: a randomized controlled trial of two drugs and three treatments

BACKGROUND

The role of bisphosphonates (BPs) in the management of patients with hypercalciuria (HC) associated with osteoporosis is still uncertain. The aim of the study was to evaluate the effect of alendronate and indapamide alone or in combination on bone mineral density (BMD) and 24-h urinary calcium excretion (24-CaU) in post-menopausal women with HC and low BMD.

METHODS

A total of 77 post-menopausal women with HC (24-CaU > 4 mg/kg/day) and low BMD [T-score < -2.0 at lumbar spine (LS), femoral neck (FN) or total hip (TH)] from two centres of Northern Italy were randomized to receive indapamide 2.5 mg daily alone (24 patients, IND group), alendronate 70 mg weekly alone (27 patients, ALN group) or the combination therapy (26 patients, ALN + IND group). Throughout the study, all subjects received daily calcium supplements, depending on their dietary intake, to maintain a daily input of 1000 mg. Patients were instructed to increase water intake up to 2000 mL daily. The percentage and absolute changes of BMD at LS, FN and TH, and the variation of 24-CaU from baseline at 1 year were the primary outcomes. Serum calcium, phosphate, parathyroid hormone and bone alkaline phosphatase were also measured.

RESULTS

Overall 67 women completed the study and were included in the final analysis. Patients in the three groups were similar with regard to baseline characteristics. BMD did not significantly change from baseline after 1 year of treatment with indapamide (LS: +1 +/- 3.1%; FN: -0.3 +/- 3.5%; TH: -0.4 +/- 3.1%), while it showed a significant increase from baseline in the other two groups (ALN; LS: +5.8 +/- 4.2%, P < 0.001; FN: +3.9 +/- 7.9%, P = 0.018; TH: +2 +/- 3.6%, P = 0.006) (ALN + IND; LS: +8.2 +/- 5.3%, P < 0.001; FN: +4.9 +/- 6.7%, P = 0.007; TH: +2.9 +/- 4.2%, P = 0.004). Patients in the combination group showed a significantly higher increase of BMD at LS compared to ALN (P = 0.04). After 1 year, 24-CaU values significantly decreased from baseline in all groups (IND, 239 +/- 78 versus 364 +/- 44, P < 0.001) (ALN, 279 +/- 68 versus 379 +/- 79, P < 0.001) (ALN + IND, 191 +/- 68 versus 390 +/- 55, P < 0.001). The mean percentage decrease of 24-CaU in ALN + IND group (-50%) was significantly greater compared to ALN (-24%, P < 0.001) and IND (-35%, P = 0.012).

CONCLUSIONS

These results show a benefit, in terms of BMD improvement and 24-CaU reduction, associated with BPs' therapy in combination with indapamide in HC associated with osteoporosis. The combination therapy demonstrated a reduction of 24-CaU and an increase in LS BMD superior to that observed with alendronate alone. Our results support a new potential approach with BPs associated with thiazide diuretics or indapamide in the management of post-menopausal women with HC and associated bone loss. Studies on the larger sample size are needed to demonstrate the efficacy on the fracture outcome.

Fracture risk and the use of a diuretic (indapamide SR) +/- perindopril: a substudy of the Hypertension in the Very Elderly Trial (HYVET)

Background

The Hypertension in the Very Elderly Trial (HYVET) is a placebo controlled double blind trial of treating hypertension with indapamide Slow Release (SR) ± perindopril in subjects over the age of 80 years. The primary endpoints are stroke (fatal and non fatal). In view of the fact that thiazide diuretics and indapamide reduce urinary calcium and may increase bone mineral density, a fracture sub study was designed to investigate whether or not the trial anti-hypertensive treatment will reduce the fracture rate in very elderly hypertensive subjects.

Methods

In the trial considerable care is taken to ascertain any fractures and to identify risk factors for fracture, such as falls, co-morbidity, drug treatment, smoking and drinking habits, levels of activity, biochemical abnormalities, cardiac irregularities, impaired cognitive function and symptoms of orthostatic hypotension.

Potential results

The trial is expected to provide 10,500 patient years of follow-up. Given a fracture rate of 40/1000 patient years and a 20% difference in fracture rate, the power of the sub study is 58% to detect this difference at the 5% level of significance. The corresponding power for a reduction of 25% is 78%.

Conclusion

The trial is well under way, expected to complete in 2009, and on target to detect, if present, the above differences in fracture rate.

Fluids and diuretics for acute ureteric colic

BACKGROUND

Acute ureteric colic is a common cause of severe and debilitating pain. Theoretically, increasing fluid flow through the affected kidney might expedite stone passage, thereby improving symptoms more quickly. Unfortunately, for interventions such as high volume intravenous or oral fluids and diuretics that are aimed at doing this, the efficacy and safety is uncertain.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register (July 2004), the Cochrane Central Register of Controlled Trials (CENTRAL - The Cochrane Library, issue 3, 2004), MEDLINE (1966 - July 2004), EMBASE (1980 - July 2004) and handsearched reference lists of nephrology and urology textbooks, review articles, relevant trials, and abstracts from nephrology scientific meetings. We sent letters seeking information about unpublished or incomplete trials to investigators known to be involved in previous trials.

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 intravenous 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 to be included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or weight mean difference (WMD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

One trial (60 participants) was identified. This study compared no fluids for six hours versus three litres of IV fluids received over a six hour period. There was no significant difference in pain at six hours (RR 1.06, 95% CI 0.71 to 1.57), surgical stone removal (RR 1.20, 95% CI 0.41 to 3.51) or manipulation by cystoscopy (RR 0.67, 95% CI 0.21 to 2.13).

AUTHORS' CONCLUSIONS

Unfortunately, we could find no credible evidence in the literature regarding either of these two treatment modalities. Given their potential positive impact, the role of diuretics and high volume fluid therapy in acute ureteric colic should be examined to determine their safety and efficacy in facilitating stone passage.