Cumulative probability of survival among 374 patients given a diagnosis of myelodysplastic syndrome at the Fondazione IRCCS Policlinico San Matteo, Pavia, Italy, 1992–2002.

Patients were grouped according to whether or not a transfusion requirement developed during their clinical course. The two groups were compared by means of a Cox proportional-hazards regression model with time-dependent covariates. Each patient was considered as part of the transfusion-independent group as long as he or she had no need for blood transfusion and was recategorized in the transfusion-dependent group when a transfusion requirement developed. Once a regular need for blood transfusion developed, patients had a significantly lower probability of survival (hazard ratio for death, 1.58; P = 0.005).
 Reproduced with permission and minor changes from: Cazzola M, Malcovati L. Myelodysplastic syndromes—coping with ineffective hematopoiesis. N Engl J Med. 2005;352:536–538.