Kidney stones: Why drinking more water alone may not prevent recurrence

A major Lancet study finds hydration alone may not prevent kidney stone recurrence, as adherence challenges and individual differences limit the effectiveness of water-based prevention strategies

If you’ve been told that drinking more water can help prevent kidney stones, a new study suggests that may not be enough. 

The study, Prevention of urinary stones with hydration: a randomised clinical trial of an adherence intervention, published in The Lancet, found that even when people increased their fluid intake with structured support, it did not significantly reduce the chances of stones coming back. The findings highlight how difficult it is to maintain high fluid intake and suggest that prevention may need a more personalised approach.

What are kidney stones, and why do they form?

According to the Cleveland Clinic, an American nonprofit academic medical centre based in Cleveland, Ohio, kidney stones are hard mineral deposits that form in the kidneys and can cause severe, often sudden pain. Most kidney stones pass naturally through urine, but the process can be extremely painful as they travel through the urinary tract. 

 

About 1 in 10 people will get a kidney stone during their lifetime, according to the Cleveland Clinic. They are most common in men in their 30s and 40s.

Does drinking more water prevent kidney stones?

The researchers say that increasing fluid intake has long been considered one of the simplest and most effective ways to prevent kidney stones. This was because of the logic that more water dilutes urine, reducing the concentration of minerals that form stones. 

However, this new study suggests that while hydration is important, it may not be sufficient on its own, especially in real-world conditions where consistency is difficult. 

What did the study on hydration and kidney stones find?

The study, conducted by the Urinary Stone Disease Research Network and coordinated by the Duke Clinical Research Institute, tested whether a structured behavioural programme could help people drink enough fluids to prevent recurrence. 

It included 1,658 adolescents and adults across six major US clinical centres and followed them for two years. 

Participants were divided into two groups:

• Standard care
• A behavioural hydration programme

The behavioural hydration intervention included:

• Bluetooth-enabled smart water bottles to track intake
• Personalised “fluid prescriptions” based on urine output
• Financial incentives
• Reminder text messages
• Health coaching

Each participant’s goal was to achieve a urine output of at least 2.5 litres per day. 

The researchers observed that participants in the behavioural programme did drink more fluids and increased their urine output. However, the increase was not enough to reduce the overall rate of symptomatic kidney stone recurrence.

Why didn’t increased water intake reduce kidney stone recurrence?

According to a statement on the Duke Clinical Research Institute website, the main issue was adherence. 

“The trial results show that despite the importance of high fluid intake to prevent stone recurrence, achieving and maintaining very high fluid intake is more challenging than we often assume for people with urinary stone disease,” said Charles Scales, MD, co-senior author of the study. 

“The challenge of adherence likely contributes to the relatively high rate of stone recurrence in people with this chronic condition,” he added. 

Thus, even motivated individuals with support systems struggled to consistently meet high hydration targets.

Does this mean hydration is not important for kidney stones?

Not at all. The researchers stressed that hydration remains a cornerstone of kidney stone prevention. 

What the study highlights is that:

• Simply telling people to drink more water is not enough
• Even structured programmes may fall short
• Real-world barriers like work routines, habits, and lifestyle play a major role

Therefore, the researchers call for a personalised approach as hydration needs differ from person to person. The study authors say that a one-size-fits-all hydration target may not work because fluid needs vary based on:

• Age
• Body size
• Lifestyle
• Overall health

“Rather than asking every patient to meet the same fluid goal, we should determine who benefits from which targets,” said Gregory E Tasian, MD, co-senior author, in the statement.

How can kidney stone prevention strategies improve?

The findings of the study point towards more personalised and multi-pronged strategies, including:

• Individualised hydration goals
• Behavioural interventions tailored to daily routines
• Medical therapies to keep minerals dissolved in urine

Researchers emphasise that prevention needs to go beyond hydration alone and address the complexity of human behaviour and biology.

What should patients do to prevent kidney stones?

If you are prone to kidney stones:

• Continue to stay well hydrated
• Follow medical advice on diet and lifestyle
• Understand that consistency matters more than short-term effort
• Speak to your doctor about personalised prevention strategies

As Alana Desai, MD, first author of the study, noted in the statement, “Most people would appreciate a simple means to reduce their chances of experiencing another event.”