title: QTc interval in a sample of long-term schizophrenia inpatients.
abstract: This naturalistic study attempted to determine the prevalence of prolonged QTc interval in a relatively large population of inpatients hospitalized with chronic schizophrenia, and to explore QTc relationship with demographic variables, metabolic parameters and prescribed treatments. All inpatients from a Spanish long-term psychiatric hospital were cross-sectionally investigated to determine the prevalence of QTc prolongation and metabolic syndrome. The sample with a DSM-IV diagnosis of schizophrenia included 171 Caucasian inpatients, all of Spanish origin. A prolonged QTc interval was defined as >450 ms in men and >470 ms in women. The relationships between QTc and other continuous variables were assessed using a linear regression model with QTc as the dependent variable. Only 10 patients (6%) had a prolonged QTc interval; one case was possibly explained by hypokalemia. Three patients (2%) had a QTc > 500 ms. Gender, old age (> or = 50 years old), current smoking, systolic blood pressure, HDL cholesterol and history of arrhythmia were found to have significant effects on QTc interval in a linear regression analysis. After controlling for significant variables, the mean QTc interval was not significantly influenced by antipsychotic dose, type of antipsychotic treatment, the use of depot antipsychotics, or the number of different antipsychotics prescribed. Our study focused on long-term schizophrenia inpatients with frequent antipsychotic polypharmacy and high antipsychotic doses, and suggested that after excluding the case with hypokalemia length of QTc was associated with history of arrhythmias and with metabolic factors, while the effects of antipsychotic compound or class were not so evident.
authors.affiliation: Department of Psychiatry, Complejo Hospitalario Universitario de Santiago, Santiago de Compostela, Spain.
authors.forename: Ramón
authors.initials: R
authors.lastname: Ramos-Ríos
authors.forename: Manuel
authors.initials: M
authors.lastname: Arrojo-Romero
authors.forename: Eduardo
authors.initials: E
authors.lastname: Paz-Silva
authors.forename: Fernando
authors.initials: F
authors.lastname: Carballal-Calvo
authors.forename: José L
authors.initials: JL
authors.lastname: Bouzón-Barreiro
authors.forename: Jorge
authors.initials: J
authors.lastname: Seoane-Prado
authors.forename: Rosario
authors.initials: R
authors.lastname: Codesido-Barcala
authors.forename: Alicia
authors.initials: A
authors.lastname: Crespí-Armenteros
authors.forename: Ramón
authors.initials: R
authors.lastname: Fernández-Pérez
authors.forename: Javier D
authors.initials: JD
authors.lastname: López-Moríñigo
authors.forename: Ignacio
authors.initials: I
authors.lastname: Tortajada-Bonaselt
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Diaz
authors.forename: Jose
authors.initials: J
authors.lastname: de Leon
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use*; D015992:Body Mass Index; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007297:Inpatients; D008133:Long QT Syndrome / Q000139:chemically induced* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000378:metabolism; D015995:Prevalence; D012044:Regression Analysis; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D012737:Sex Factors
chemical_list: D014150:Antipsychotic Agents; D011188:Potassium