A method of determining the likelihood that a HMG-CoA reductase inhibitor treatment will reduce the risk of a cardiovascular event in an individual, by (i) detecting a level of one or two or more non-steroidal lipid species in a biological sample obtained from the individual at a time point before or after treatment； (ii) comparing the level one or two or more lipid species, or a ratio of the level of two lipid species, from step (i) in the sample to a reference level or ratio for the lipid species； and (iii) determining whether the treatment is likely or not to reduce the risk of the cardiovascular event in the individual on the basis of the comparison. A method of treatment comprising administering an HMG-CoA reductase inhibitor treatment regimen to the individual after ascertaining the likelihood that the HMG-CoA reductase inhibitor treatment regimen will reduce the risk of a cardiovascular event in the individual by the above method. A method of treatment or prophylaxis of an individual to reduce the risk of a cardiovascular event, the method comprising administering an HMG-CoA reductase inhibitor treatment regimen in combination with fatty acid supplementation comprising a lipid comprising an omega-6 fatty acid or arachidonic acid treatment regimen. A method of treating a subject at risk of a cardiovascular event, the method comprising administering an agent that lowers the plasma levels of phosphatidylinositol in the subject.L'invention concerne un procédé de détermination de la probabilité qu'un traitement par inhibiteur de la HMG-CoA réductase réduira le risque d'un événement cardiovasculaire chez un individu, le procédé consistant (i) à détecter un niveau d'une ou de deux espèces lipidiques non stéroïdiennes dans un échantillon biologique prélevé chez l'individu à un instant avant ou après le traitement ； (ii) à comparer le niveau d'une ou de deux espèces lipidiques ou plus, ou un rapport du taux de deux espèces lipidiques, de l'étape (i) dans l'échantillon
