ABSTRACT
OBJECTIVE: To analyse the rate of occurrence and the clinical variables associated with readmission of patients who had previously been discharged after admission for COVID-19. SETTING: University hospital in Madrid (Spain). PARTICIPANTS: Sixty-one patients (74% male) who presented COVID-19 were readmitted during the 3 weeks after discharge from hospital. INTERVENTIONS: Nested case-control study paired (1:1 ratio) by age, sex and period of admission. OUTCOME MEASURES: Rate of readmission rate of patients discharged after suffering COVID-19 and identification of the clinical variables associated with it. RESULTS: Out of 1368 patients who were discharged during the study period, 61 patients (4.4%) were readmitted. Immunocompromised patients (N=10.2%) were at increased risk for readmission (p=0.04). There was also a trend towards a higher probability of readmission in hypertensive patients (p=0.07). Cases had had a shorter hospital stay and a higher prevalence of fever during the 48 hours prior to discharge. There were no significant differences in oxygen levels measured at admission and discharge by pulse oximetry intra-subject or between the groups. Neutrophil-to-lymphocyte ratio at hospital admission tended to be higher in cases than in controls (p=0.06). Neither glucocorticoids nor anticoagulants prescribed at hospital discharge were associated with a lower readmission rate. Patients who were readmitted due to a thrombotic event (8 patients, 13.1%) presented a higher level of D-dimer at discharge of initial admission. CONCLUSION: The rate of readmission after discharge from hospital for COVID-19 was low. Immunocompromised patients and those presenting with fever during the 48 hours prior to discharge were at greater risk of readmission to hospital.