Differential risk factors for early and later hospital readmission of older patients

Background and aims: This study aimed at analyzing rates and factors associated with early and later readmission (0–1 month and 2–3 months after discharge, respectively) of older people after index hospitalization. Methods: This prospective observational study was conducted in two teaching hospitals. People 70 years and over were interviewed within 48 h of emergency admission. Socio-demographic and medical factors were collected, together with functional factors including Activities of Daily Living (basis and instrumental), cognitive state, and geriatric syndromes. Medical diagnosis, length of stay, and destination were collected at discharge, and patients were followed up by phone 1 and 3 months after discharge. During these interviews, outcomes on readmission, institutionalization, need for help, and death were evaluated. Results: The population of 625 patients had a mean age of 80.0 years. The rate of early readmission (0–1 month) was 10.7% and the overall rate within 3 months was 23.1%. Logistic regression analysis showed that variables predicting early readmission were previous hospitalization within 3 months, a longer length of stay, and a discharge diagnosis in chapter 8 (respiratory system) and chapter 10 (genito-urinary system) of the ICD-9-CM. Variables predicting later readmission were previous hospitalization within 3 months, a discharge diagnosis in chapter 7 (circulatory system) of the ICD-9-CM, and a poor pre-admission IADL score. Conclusions: In a medicalized population of older people, several risk factors may be identified for 0–1 month and 2–3 month readmission. Besides severe morbidities at discharge, diagnoses and previous hospitalization, pre-admission IADL was an independent risk factor for 2–3 month readmission.