Characteristics and predictors of long-term institutionalization in patients with schizophrenia

Patients with schizophrenia requiring long-term institutionalization represent those with the worst outcome, leading to personal costs for patients and relatives and constituting a large economical burden for society.

To identify characteristics and predictors of outcome of institutionalized patients with schizophrenia.

One-year follow-up cohort study, utilizing the Danish national registers, of all institutionalized and non-institutionalized patients with schizophrenia in Denmark with an ICD-10 lifetime diagnosis of schizophrenia (F20.0-F20.9) since 1969 and alive at the index date of January 1st 2006 (total number 22,395).

Compared with non-institutionalized patients, institutionalized patients (n=2188; 9.8%) had earlier onset of schizophrenia and lower scholastic achievements, were more often diagnosed with a hebephrenic subtype (odds ratio (OR), 2.34; 95% confidence interval (CI), 1.95-2.80; p<0.001), received higher dosages of antipsychotics, more antipsychotic polypharmacy and more concomitant medications, and had more substance misuse and early retirement pension. In a logistic regression model adjusted for sex and age, institutionalized patients with schizophrenia had an increased risk of type II diabetes (AOR, 1.22; CI, 1.01-1.42; p<0.001), but the mean age of onset of type II diabetes did not differ. The mean patient age was higher in the institutionalized group (62.7 vs. 58.7 years; p=0.027), which was mainly driven by absence of death from suicide in the institutionalized group. Multivariate predictors of institutionalization included hebephrenic subtype, a diagnosis of epilepsy, early retirement pension, male sex, a greater proportion of prior hospitalization, and substance misuse.

Institutionalized patients with schizophrenia had a more complex and worse outcome of the disorder, except for less suicide, illustrated by lower scholastic achievement, receiving higher dosages of antipsychotic medications, more concomitant medications and more prior bed-days.