Mineral Water for Prevention of Renal Stones

Study Overview
=================
Brief Summary
-----------------
The investigators would like to assess if the intake of high bicarbonate mineral water would not only increase total fluid intake but will also be able to give patients the additional benefit of correcting the urinary abnormalities which may predispose them to stone formation.

Detailed Description
-----------------
The life time risk of developing nephrolithiasis is about 10-15% in the western world, but can be as high as 20-25% in the middle east. Evidence suggests that the incidence and prevalence of kidney stones is increasing globally which represent a significant economic burden. Besides the lack of hydration, the most common metabolic abnormalities associated with calcium stones are hypercalciuria, hypocitraturia and hyperoxaluria. In addition, low urinary pH from consumption of non-dairy animal protein has been associated with reduced urinary citrate and increased uric acid stones which form a nidus for subsequent calcium oxalate precipitates. Dietary modification is the first line approach in the treatment of idiopathic calcium oxalate (CaOx) nephrolithiasis. General advice includes adequate hydration, avoiding oxalate-rich foods, and consumption of an adequate amount of calcium. Adequate hydration is an easy and effective way of preventing stones. Siener et al found in healthy men, consumption of mineral water rich in magnesium and bicarbonate resulted in favourable changes in urinary pH, magnesium and citrate excretion (inhibitors of CaOx stone formation). Our pilot study in 10 young and healthy surgical residents also revealed similar results after drinking bicarbonate rich mineral water for 1 week. In this study, the investigators compared the effect of drinking bicarbonate rich mineral water with plain water on urine biochemistry in a prospective randomized study in patients with known CaOx stones. The investigators hypothesize that the intake of bicarbonate rich mineral water, particularly at meal times, reduces stone risk via reduction in urinary oxalate through increased intestinal oxalate binding with dietary calcium. Other potential benefits of mineral water include increased urinary stone inhibitors like magnesium, citrate and alkalinisation of urine.

Official Title
-----------------
Mineral Water for Prevention of Renal Stones

Conditions
-----------------
Calcium Oxalate Urolithiasis

Intervention / Treatment
-----------------
* Other: Mineral water
* Other: Plain water


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: patients with proven Calcium Oxalate (CaOx) stone (CaOx >50% by infrared spectroscopy) from Jan 2018 to Aug 2019 in Singapore General Hospital all stone formers had suffered spontaneous passage or surgical removal of a urinary calculus during the study period. Exclusion Criteria: presence of urinary tract infection severe cardiovascular insufficiency previously diagnosed causal metabolic disease such as hyperparathyroidism, renal tubular acidosis, primary hyperoxaluria, Wilson's disease, Cushing disease, osteoporosis and malignant diseases. pregnant women chronic intestinal diseases history of previous bowel resection participation in competitive sports

Ages Eligible for Study
-----------------
Minimum Age: 21 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Mineral water group<br>The mineral water group were instructed to consume 1.25L of a commercially supplied bicarbonate rich mineral water per day at meal times, supplemented by other fluid intake up to 2.5 - 3L/day. | Other: Mineral water<br>* Drinking mineral water for 12 weeks<br>|
| Active Comparator: Plain water group<br>The plain water group consumed only plain water up to 2.5 - 3L/day. | Other: Plain water<br>* Drinking plain water for 12 weeks<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes of Tiselius Index | compare Tiselius Index (24h urine analysis) at week 1, 4, 8 and 12 to baseline (week 0) | 1, 4, 8 and 12 weeks | 
| changes of urinary oxalate level (mmol/24h) | compare urinary oxalate level (24h urine analysis) at week 1, 4, 8 and 12 to baseline (week 0) | 1, 4, 8 and 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes of other stone inhibitor/promoter (mmol/24h) | compare Magnesium, Citrate, Sodium, Calcium, Uric Acid (24h urine analysis) at week 1, 4, 8 and 12 to baseline (week 0) | 1, 4, 8 and 12 weeks | 
| changes of urinary volume (ml/24h) | compare urinary volume (24h urine analysis) at week 1, 4, 8 and 12 to baseline (week 0) | 1, 4, 8 and 12 weeks | 
| changes of urinary pH | compare urinary pH (24h urine analysis) at week 1, 4, 8 and 12 to baseline (week 0) | 1, 4, 8 and 12 weeks | 
| changes of serum electrolytes (mmol/L) | compare serum sodium, potassium, calcium, phosphate, bicarbonate and uric acid at baseline (week 0) and the end of the study (week 12) | 12 weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Mineral water, Disease prevention, 24h urine analysis