The authors regret that in preparation of a new article based on the same data as in the previous published article [1], we unfortunately discovered two errors in the dataset. Some cases of hyponatremia as a secondary diagnosis had erroneously been included as primary diagnosis of hyponatremia. The corrected number of cases admitted with a primary diagnosis of hyponatremia decreased to 11,213 instead of 14,359 as reported in the article, and as a consequence the number of matched controls decreased to 44,801 instead of 57,382.