[The factors associated with a lengthy hospital stay in a third-level unit].

A descriptive, cross-sectional and retrospective design was developed in order to assess the frequency of patients with lengthy hospital stay (LHS) and associated factors at the Hospital de Especialidades, Centro Médico Nacional Siglo XXI, IMSS, in Mexico City from January to April, 1993. Some 2,488 patients were discharged during this period and 541 were selected at random. There were 23.9% (n = 131) of patients who had LHS, with a specific mean of 7.7 days and a total mean of 18 days of hospital stay compared with 5 days for those patients who did not have LHS. The associated factors were: patient's origin, admission conditions, complications, hospital infections, category and specialty of attending physician, delay in laboratory and diagnostic imaging exams and results, delay in surgical interventions, and need of outside transportation at time of discharge. Characteristics of patients with greater probabilities of having LHS are outside origin, diagnosis of malignant tumor, complications, hospital infections, and delay in laboratory exams and in surgical interventions. Some of these characteristics can be modified in order to improve LHS and quality of medical care. Further investigations are required to individually analyze these characteristics as well as the justification for LHS and its costs.