Hyponatremia increases the risk of death and complications after nonemergency procedures. A survey of 964,263 surgical patients found that 75,423 (or one in 13) had hyponatremia. Preoperative hyponatremia was associated with a higher risk of death, with a risk of 9.6% among patients with moderate-to-severe hyponatremia (a sodium level under 130 mEq/L), compared with 1.3% among patients with normal sodium levels. Hyponatremia also increased the risks of major coronary events, wound infections, and pneumonia. The researchers conclude in the October 22 Archives of Internal Medicine that "hyponatremia should be considered as a sensitive surrogate marker for comorbidity and disease severity." However, they write, further studies are needed to determine whether increasing sodium levels before surgery will mitigate those risks.