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Title:

Antipsychotic Dose Mediates the Association between Polypharmacy and Corrected QT Interval.

Document type:
Journal Article; Multicenter Study
Author(s):
Barbui, Corrado; Bighelli, Irene; Carrà, Giuseppe; Castellazzi, Mariasole; Lucii, Claudio; Martinotti, Giovanni; Nosè, Michela; Ostuzzi, Giovanni
Abstract:
Antipsychotic (AP) drugs have the potential to cause prolongation of the QT interval corrected for heart rate (QTc). As this risk is dose-dependent, it may be associated with the number of AP drugs concurrently prescribed, which is known to be associated with increased cumulative equivalent AP dosage. This study analysed whether AP dose mediates the relationship between polypharmacy and QTc interval. We used data from a cross-sectional survey that investigated the prevalence of QTc lengthening among people with psychiatric illnesses in Italy. AP polypharmacy was tested for evidence of association with AP dose and QTc interval using the Baron and Kenny mediational model. A total of 725 patients were included in this analysis. Of these, 186 (26%) were treated with two or more AP drugs (AP polypharmacy). The mean cumulative AP dose was significantly higher in those receiving AP polypharmacy (prescribed daily dose/defined daily dose = 2.93, standard deviation 1.31) than monotherapy (prescribed daily dose/defined daily dose = 0.82, standard deviation 0.77) (z = -12.62, p < 0.001). Similarly, the mean QTc interval was significantly longer in those receiving AP polypharmacy (mean = 420.86 milliseconds, standard deviation 27.16) than monotherapy (mean = 413.42 milliseconds, standard deviation 31.54) (z = -2.70, p = 0.006). The Baron and Kenny mediational analysis showed that, after adjustment for confounding variables, AP dose mediates the association between polypharmacy and QTc interval. The present study found that AP polypharmacy is associated with QTc interval, and this effect is mediated by AP dose. Given the high prevalence of AP polypharmacy in real-world clinical practice, clinicians should consider not only the myriad risk factors for QTc prolongation in their patients, but also that adding a second AP drug may further increase risk as compared with monotherapy.
Journal title abbreviation:
PLoS ONE
Year:
2016
Journal volume:
11
Journal issue:
2
Pages contribution:
e0148212
Language:
eng
Fulltext / DOI:
doi:10.1371/journal.pone.0148212
Pubmed ID:
http://view.ncbi.nlm.nih.gov/pubmed/26840602
Print-ISSN:
1932-6203
TUM Institution:
Klinik und Poliklinik für Psychiatrie und Psychotherapie
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