The present invention relates to the field of laboratory diagnostics. Specifically, means and methods for determining the risk of mortality in a patient based on homoarginine and to reduce the risk of mortality by administration of homoarginine are disclosed. Moreover, the present invention relates to the use of homoarginine for the preparation of a medicament for the treatment of a patient having an increased risk of mortality caused by stroke or a cardiac cause. Furthermore, the present application relates to a pharmaceutical composition comprising homoarginine and a composition for foodstuff supplement comprising homoarginine.