This study examines factors influencing the evolution of West syndrome to Lennox-Gastaut syndrome. The study population comprised 98 patients diagnosed with West syndrome and monitored for at least 3 years. During follow-up, West syndrome evolved to Lennox-Gastaut syndrome in 48 of the 98 patients. Etiology analysis indicated that West syndrome was cryptogenic in 36 patients (36.7%) and symptomatic in 62 (63.3%). West syndrome was managed with antiepileptic drugs in 31 patients, ketogenic diets in 33 patients, hormonal therapy with prednisolone in 45 patients and with adrenocorticotropic hormone in 15 patients, epileptic surgery in 3 patients, and either no treatment or only herbal medication in 4 patients. The risk of developing Lennox-Gastaut syndrome was significantly lower in patients who were placed on a ketogenic diet, given prednisolone or adrenocorticotropic hormone, or treated with a combination of these two therapies (bivariate logistic regression analysis, P < 0.05). There was no relationship between the development of Lennox-Gastaut syndrome and age at West syndrome onset or disease etiology. In conclusion, a ketogenic diet and hormonal therapy may play key roles in preventing encephalopathy in patients with West syndrome.