Background: The prospective payment system for the French short-stay hospitals creates a financial incentive to reduce length of stay. The potential impact of the resulting decrease in length of stay on the quality of healthcare is unknown. Readmission rates are valid outcome indicators for some clinical procedures.
Methods: Retrospective study of the association between length of stay and unplanned readmissions related to the initial stay, for two procedures: cholecystectomy and vaginal delivery.
Data: Administrative diagnosis-related groups database of "Assistance publique-Hôpitaux de Paris", a large teaching hospital, for years 2002 to 2005.
Results: The risk of readmission according to length of stay, taking age, sex, comorbidity, hospital and year of admission into account, followed a J-shaped curve for both procedures. The probability of readmission was higher for very short stays, with odds ratios and 95% confidence intervals of 6.03 [2.67-13.59] for cholecystectomies (1- versus 3-night stays), and of 1.74 [1.05-2.91] for vaginal deliveries (2- versus 3-night stays).
Conclusion: For both procedures, the shortest lengths of stay are associated with a higher readmission probability. Suitable indicators derived from administrative databases would enable monitoring of the association between length of stay and readmissions.