Kidney stones increase risk of later kidney disease

A history of kidney stones carries a small but significant increase in the risk of loss of kidney function—ESRD—reports a study in the British Medical Journal.

Using the Alberta Kidney Disease Network database, the researchers identified more than 3 million adult patients who were free of ESRD or a history of pyelonephritis at baseline. Nearly 2 million had available data on outpatient serum creatinine levels. During follow-up, one or more kidney stones developed in about 27,000 patients—a rate of 0.8 percent. Kidney stones were evaluated as a risk factor for adverse renal outcomes, including incident ESRD, stage 3b to 5 chronic kidney disease (CKD), or sustained doubling of serum creatinine level.

The rates of adverse renal outcomes during follow-up were 0.2 percent for ESRD, 4.0 percent for stage 3b to 5 CKD, and 3.0 percent for doubling of serum creatinine. Compared with stone-free patients, those with even one episode of kidney stones were at increased risk of all three outcomes: adjusted hazard ratio 2.16 for ESRD, 1.74 for CKD, and 1.94 for doubling of serum creatinine.

The excess risk related to kidney stones appeared greater for women and for people younger than 50, although the association was significant for both sexes and all age groups. Absolute increases in risk were small: the unadjusted ESRD rate was 2.48 per million person-days in those with kidney stones versus 0.52 per million in those without stones.

Kidney stones are a common and potentially preventable problem. There are few data on their possible association with later kidney disease.

This population-based study finds significant increases in the risk of ESRD and other adverse renal outcomes in patients with even a single episode of kidney stones. Absolute increases in risk are small. More research is needed to understand the mechanism of the associations and the best way to prevent kidney stones, particularly in young women [Alexander RT, el al. Kidney stones and kidney function loss: a cohort study. BMJ 2012; 345:e5287].