Introduction: Few studies assess postoperative outcomes after discharge in the ambulatory setting. The aim of this study was to investigate postoperative pain and adverse effects at 24 h and at 7 days after day surgery using an e-health follow-up smartphone-based application named SATELIA®. Materials and methods: This retrospective, observational and monocentric cohort study was conducted at the University Hospital of Bordeaux. All eligible patients for SATELIA® follow-up between May 2018 and June 2019 were screened for the analysis. Data were extracted from two databases. Those with a missing primary outcome were excluded from the analysis. The main outcome was the worst pain score on POD 1, self-reported via SATELIA®. The secondary outcomes were the incidence of adverse effects on POD1, as well as the worst pain score and adverse effects on POD7. Quantitative data were reported by the median (IQR) and categorical data were presented as absolute numbers (%). Results: A total of 2283 patients were screened for analysis, from which 592 were excluded due to missing data for the main outcome; 1691 patients were thus finally included. The median worst pain score at POD 1 was 3.0 (1.0-5.0); 35.5% (n = 601/1691) and 29.1% (n = 492/1691) of the patients reported moderate-to-severe pain at POD1 and POD7, respectively. Conclusion: This retrospective study shows that 35.5% of patients experience moderate-to-severe pain after day surgery. Even if SATELIA® should be further developed and evaluated, it also demonstrates the interest of using phone based software to follow patients after discharge and ensure a better personalised management.< Leer menos