Risk factors for general medicine readmissions and association with mortality

To investigate general medicine readmissions for risk factors and association with mortality.

A case control study was performed comparing the characteristics of 30-day general medicine patients readmitted between 1 January to 30 June 2012 to a general medicine service at Capital and Coast District Health Board (Wellington region, New Zealand) with an equal number of randomly selected patients not readmitted to the service during the same time period.

197 patients discharged from general medicine were readmitted during the 6-month study period. There were no differences in the sex, ethnicity, residential care at admission, history of dementia, length of admission or weekend discharge of readmitted patients compared to non-readmitted patients. The mean age, number of medications and comorbidities score were higher in the readmission group. Readmission (even after controlling for age, polypharmacy, and comorbidities) was a strong predictor of 1-year all-cause mortality, with an odds ratio of 2.2. Twenty-one percent of readmission patients had more than one general medicine readmission, up to 30 days between each, with even higher mortality rate compared to one readmission (49% vs. 28%).

Readmission to general medicine is strongly associated with older age, polypharmacy, and multiple comorbidities. Readmission is an independent strong risk factor for 1-year mortality, with this risk increasing after multiple readmissions. Readmissions can be a marker of deteriorating patient's condition, and a discussion in relation to prognosis, ceiling of treatment, resuscitation status documentation and advance directive may be warranted.