Primary care management of cardiovascular risk for people with severe mental illnesses: the Primrose research programme including cluster RCT

Abstract

Background Effective interventions are needed to prevent cardiovascular disease (CVD) in people with severe mental illnesses (SMI) because their risk of CVD is higher than that of the general population. Objectives (1) Develop and validate risk models for predicting CVD events in people with SMI and evaluate their cost-effectiveness, (2) develop an intervention to reduce levels of cholesterol and CVD risk in SMI and (3) test the clinical effectiveness and cost-effectiveness of this new intervention in primary care. Design Mixed methods with patient and public involvement throughout. The mixed methods were (1) a prospective cohort and risk score validation study and cost-effectiveness modelling, (2) development work (focus groups, updated systematic review of interventions, primary care database studies investigating statin prescribing and effectiveness) and (3) cluster randomised controlled trial (RCT) assessing the clinical effectiveness and cost-effectiveness of a new practitioner-led intervention, and fidelity assessment of audio-recorded appointments. Setting General practices across England. Participants All studies included adults with SMI (schizophrenia, bipolar disorder or other non-organic psychosis). The RCT included adults with SMI and two or more CVD risk factors. Interventions The intervention consisted of 8–12 appointments with a practice nurse/health-care assistant over 6 months, involving collaborative behavioural approaches to CVD risk factors. The intervention was compared with routine practice with a general practitioner (GP). Main outcome measures The primary outcome for the risk score work was CVD events, in the cost-effectiveness modelling it was quality-adjusted life-years (QALYs) and in the RCT it was level of total cholesterol. Data sources Databases studies used The Health Improvement Network (THIN). Intervention development work included focus groups and systematic reviews. The RCT collected patient self-reported and routine NHS GP data. Intervention appointments were audio-recorded. Results Two CVD risk score models were developed and validated in 38,824 people with SMI in THIN: the Primrose lipid model requiring cholesterol levels, and the Primrose body mass index (BMI) model with no blood test. These models performed better than published Cox Framingham models. In health economic modelling, the Primrose BMI model was most cost-effective when used as an algorithm to drive statin prescriptions. Focus groups identified barriers to, and facilitators of, reducing CVD risk in SMI including patient engagement and motivation, staff confidence, involving supportive others, goal-setting and continuity of care. Findings were synthesised with evidence from updated systematic reviews to create the Primrose intervention and training programme. THIN cohort studies in 16,854 people with SMI demonstrated that statins effectively reduced levels of cholesterol, with similar effect sizes to those in general population studies over 12–24 months (mean decrease 1.2 mmol/l). Cluster RCT: 76 GP practices were randomised to the Primrose intervention (n = 38) or treatment as usual (TAU) (n = 38). The primary outcome (level of cholesterol) was analysed for 137 out of 155 participants in Primrose and 152 out of 172 in TAU. There was no difference in levels of cholesterol at 12 months [5.4 mmol/l Primrose vs. 5.5 mmol/l TAU; coefficient 0.03; 95% confidence interval (CI) –0.22 to 0.29], nor in secondary outcomes related to cardiometabolic parameters, well-being or medication adherence. Mean cholesterol levels decreased over 12 months in both arms (–0.22 mmol/l Primrose vs. –0.39 mmol/l TAU). There was a significant reduction in the cost of inpatient mental health attendances (–£799, 95% CI –£1480 to –£117) and total health-care costs (–£895, 95% CI –£1631 to –£160; p = 0.012) in the intervention group, but no significant difference in QALYs (–0.011, 95% CI –0.034 to 0.011). A total of 69% of patients attended two or more Primrose appointments. Audiotapes revealed moderate fidelity to intervention delivery (67.7%). Statin prescribing and adherence was rarely addressed. Limitations RCT participants and practices may not represent all UK practices. CVD care in the TAU arm may have been enhanced by trial procedures involving CVD risk screening and feedback. Conclusions SMI-specific CVD risk scores better predict new CVD if used to guide statin prescribing in SMI. Statins are effective in reducing levels of cholesterol in people with SMI in UK clinical practice. This primary care RCT evaluated an evidence-based practitioner-led intervention that was well attended by patients and intervention components were delivered. No superiority was shown for the new intervention over TAU for level of cholesterol, but cholesterol levels decreased over 12 months in both arms and the intervention showed fewer inpatient admissions. There was no difference in cholesterol levels between the intervention and TAU arms, which might reflect better than standard general practice care in TAU, heterogeneity in intervention delivery or suboptimal emphasis on statins. Future work The new risk score should be updated, deployed and tested in different settings and compared with the latest versions of CVD risk scores in different countries. Future research on CVD risk interventions should emphasise statin prescriptions more. The mechanism behind lower costs with the Primrose intervention needs exploring, including SMI-related training and offering frequent support to people with SMI in primary care. Trial registration Current Controlled Trials ISRCTN13762819. Funding This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 7, No. 2. See the NIHR Journals Library website for further project information. Professor David Osborn is supported by the University College London Hospital NIHR Biomedical Research Centre and he was also in part supported by the NIHR Collaboration for Leadership in Applied Health Research and Care (CLAHRC) North Thames at Barts Health NHS Trust.