Correlation of unilateral urolithiasis with sleep posture

Area of Science:

• Nephrology
• Urology
• Sleep Medicine

Background:

• Recurrent kidney stones often form on the same side, but the cause of unilateral urolithiasis is frequently unknown.
• Standard metabolic testing does not always identify a cause for recurrent stone formation.
• Existing research suggests sleep posture might influence kidney blood flow.

Purpose of the Study:

• To explore the relationship between sleep posture and the development of unilateral kidney stones.
• To determine if sleeping position correlates with the side of recurrent stone formation.

Main Methods:

• A prospective study involved 110 patients with a history of recurrent unilateral kidney stones.
• A questionnaire assessed participants' habitual sleep postures (e.g., right side down, left side down).
• Statistical analysis (chi-square test) compared stone side with sleep posture.

Main Results:

• 76% of patients with unilateral stones slept predominantly on one side.
• The side of stone formation matched the dependent sleep side in 76% of cases (p = 0.008).
• Positive predictive values for ipsilateral stone formation were 82% for right-side sleeping and 70% for left-side sleeping.

Conclusions:

• Sleep posture may be linked to recurrent unilateral kidney stone formation.
• Altered renal hemodynamics during sleep due to posture could be a contributing factor.
• This finding suggests sleep position should be considered in the evaluation and prevention of unilateral urolithiasis.