Deborah Layton, Vicki Osborne, Miranda Davies, Ian Ratcliffe, Sarah Clarke, Saad AW Shakir, Joe Reilly, Tony Hale

Background

Safety studies conducted exclusively in the primary care setting may be subject to bias because of exclusion of patients (pts) who are managed predominantly within secondary care. These pts may have different characteristics and health events to those treated in primary care for similar indications. The Risk Management Plan for quetiapine extended release (Seroquel XL©) had a need to describe utilisation and monitor safety as prescribed in primary care (in a Modified Prescription-Event Monitoring (MPEM) – all indications) and in mental health secondary care (in a Specialist Cohort Event Monitoring (SCEM)-ENCePP Study reg.5412 – Schizophrenia (Schiz) and Bipolar disorder (BD) indications only).

Objectives

An ad-hoc analysis to describe the characteristics of two study cohorts prescribed Seroquel XL© for similar indications under normal conditions of use in each setting.

Methods

Exposure, selected past medical history (pmh) and prior medications use (incl. quetiapine immediate release (IR)) data were collected from forms sent to specialists Dec2009-Dec2012 and to General Practitioners (GPs) Sep2008-Feb 2013. Descriptive statistics and univariate analyses were performed (% denominator assumes no missing data).

Results

The SCEM cohort (869) inc. 258 pts (40%) with Schiz, 345 pts (53%) with BD. The MPEM cohort (13276) inc 2373 pts (18%) with Schiz, 3820 pts (30%) with BD. In those with Schiz, SCEM pts were more likely than MPEM pts to be < 30 yrs old, have a pmh of: depression, extrapyramidal symptoms (EPS) and prior antipsychotic (AP) use, but prior IR use was less likely. In those with BD, SCEM pts were more likely than MPEM pts to have a pmh of: depression, EPS, diabetes and AP use, and prior IR use was less likely.

Conclusion

In this ad-hoc analysis, SCEM pts appeared overall to have a higher burden of some pre-existing conditions (depression, EPS and diabetes) than MPEM pts, highlighting important differences in pt risk profiles. Considerations include differences in the recording of data in medical records held by specialists vs GPs. Nevertheless, these findings support the need for systematic surveillance across both primary and secondary care settings to avoid exclusion of high risk pts.