Antipsychotic use among persons with schizophrenia in Sweden and Finland, trends and differences

Abstract

Objectives

To compare the differences in prevalence of antipsychotic and adjunctive pharmacotherapy use among individuals with schizophrenia between Sweden and Finland during 2006–2016.

Methods

Nationwide register-based data were utilized for constructing two separate cohorts: all persons in Finland with a diagnosis of schizophrenia treated in inpatient care during 1972–2014, and persons in Sweden aged 16–64 with recorded diagnoses of schizophrenia in inpatient or specialized outpatient care, sickness absence or disability pension during 2005–2013. The prevalence of use was assessed as a point prevalence on 31 October each year 2006–2016, based on drug use periods modelled with the PRE2DUP method. In 2016, the Finnish cohort included 37,780 persons and Swedish cohort 25,433 persons.

Results

The most commonly used antipsychotic in 2016 was oral olanzapine in both countries (22.7% [95% CI 21.6–22.4] in Finland, 20.9% [20.4–21.4] in Sweden), followed by clozapine which was more frequently used in Finland (22.0%, 21.6–22.4) than in Sweden (14.8%, 14.4–15.3). Long-acting injectable (LAI) use was almost two times more likely in Sweden (21.6%, 95% CI 21.1–22.1) than in Finland (12.8%, 12.5–13.1), a difference which was due to more common use of FG-LAIs in Sweden. A four-fold difference was observed in Z-drugs use (19.9% in Sweden versus 5.0% in Finland).

Conclusion

Potential explanations for the observed discrepancies include differences in national treatment guidelines, methods of data collection, patient characteristics and/or attitudes towards treatment among both patients and physicians.

Keywords:

• Schizophrenia
• antipsychotic
• trends
• prevalence
• Sweden
• Finland

Acknowledgements

The funders of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. The corresponding authors had full access to all of the data and the final responsibility to submit for publication.

Disclosure statement

Jari Tiihonen, Heidi Taipale, Ellenor Mittendorfer-Rutz and Antti Tanskanen have participated in research projects funded by grants from Janssen-Cilag and Eli Lilly to their employing institution. Heidi Taipale reports personal fees from Janssen-Cilag. Jari Tiihonen reports personal fees from the Finnish Medicines Agency (Fimea), European Medicines Agency (EMA), Eli Lilly, Janssen-Cilag, Lundbeck, and Otsuka; is a member of advisory board for Lundbeck, and has received grants from the Stanley Foundation and Sigrid Jusélius Foundation. Markku Lähteenvuo is a board member of Genomi Solutions Ltd., has received honoraria from Sunovion Ltd., Orion Pharma Ltd., and Janssen-Cilag Ltd., and research funding from The Finnish Medical Foundation and Emil Aaltonen Foundation. Simon Cervenka has received grant support from AstraZeneca as a coinvestigator and has served as a speaker for Otsuka.

Authors’ contribution

Concept and design: J. T., H. T., and A. T.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: H. T., M. L., and S. C.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: H. T. and A. P.

Obtained funding: H. T. and J. T.

Additional information

Funding

This study was funded by the Finnish Ministry of Social Affairs and Health through the developmental fund for Niuvanniemi Hospital. H. T. and A. P. were funded by Academy of Finland (Grants 315969, 320107). M. L. was partly funded by personal grants from the Finnish Medical Foundation and Emil Aaltonen foundation. S. C. is supported by the Swedish Research Council (Grant no. 523-2014-3467).