Effectiveness and cost-effectiveness of serum B-type natriuretic peptide testing and monitoring in patients with heart failure in primary and secondary care: an evidence synthesis, cohort study and cost-effectiveness model

Background: Heart failure (HF) affects around 500,000 people in the UK. HF medications are frequently underprescribed and B-type natriuretic peptide (BNP)-guided therapy may help to optimise treatment. Objective: To evaluate the clinical effectiveness and cost-effectiveness of BNP-guided therapy compared with symptom-guided therapy in HF patients. Design: Systematic review, cohort study and cost-effectiveness model. Setting: A literature review and usual care in the NHS. Participants: (a) HF patients in randomised controlled trials (RCTs) of BNP-guided therapy; and (b) patients having usual care for HF in the NHS. Interventions: Systematic review: BNP-guided therapy or symptom-guided therapy in primary or secondary care. Cohort study: BNP monitored (>= 6 months' follow-up and three or more BNP tests and two or more tests per year), BNP tested (>= 1 tests but not BNP monitored) or never tested. Cost-effectiveness model: BNP-guided therapy in specialist clinics. Main outcome measures: Mortality, hospital admission (all cause and HF related) and adverse events; and quality-adjusted life-years (QALYs) for the cost-effectiveness model. Data sources: Systematic review: Individual participant or aggregate data from eligible RCTs. Cohort study: The Clinical Practice Research Datalink, Hospital Episode Statistics and National Heart Failure Audit (NHFA). Review methods: A systematic literature search (five databases, trial registries, grey literature and reference lists of publications) for published and unpublished RCTs. Results: Five RCTs contributed individual participant data (IPD) and eight RCTs contributed aggregate data (1536 participants were randomised to BNP-guided therapy and 1538 participants were randomised to symptom-guided therapy). For all-cause mortality, the hazard ratio (HR) for BNP-guided therapy was 0.87 [95% confidence interval (CI) 0.73 to 1.04]. Patients who were aged < 75 years or who had heart failure with a reduced ejection fraction (HFrEF) received the most benefit [interactions (p = 0.03): < 75 years vs. >= 75 years: HR 0.70 (95% CI 0.53 to 0.92) vs. 1.07 (95% CI 0.84 to 1.37); HFrEF vs. heart failure with a preserved ejection fraction (HFpEF): HR 0.83 (95% CI 0.68 to 1.01) vs. 1.33 (95% CI 0.83 to 2.11)]. In the cohort study, incident HF patients (1 April 2005-31 March 2013) were never tested (n = 13,632), BNP tested (n = 3392) or BNP monitored (n = 71). Median survival was 5 years; all-cause mortality was 141.5 out of 1000 person-years (95% CI 138.5 to 144.6 person-years). All-cause mortality and hospital admission rate were highest in the BNP-monitored group, and median survival among 130,433 NHFA patients (1 January 2007-1 March 2013) was 2.2 years. The admission rate was 1.1 patients per year (interquartile range 0.5-3.5 patients). In the cost-effectiveness model, in patients aged < 75 years with HFrEF or HFpEF, BNP-guided therapy improves median survival (7.98 vs. 6.46 years) with a small QALY gain (5.68 vs. 5.02) but higher lifetime costs (< 64,777 vs. alpha 58,139). BNP-guided therapy is cost-effective at a threshold of alpha 20,000 per QALY. Limitations: The limitations of the trial were a lack of IPD for most RCTs and heterogeneous interventions; the inability to identify BNP monitoring confidently, to determine medication doses or to distinguish between HFrEF and HFpEF; the use of a simplified two-state Markov model; a focus on health service costs and a paucity of data on HFpEF patients aged < 75 years and HFrEF patients aged >= 75 years. Conclusions: The efficacy of BNP-guided therapy in specialist HF clinics is uncertain. If efficacious, it would be cost-effective for patients aged < 75 years with HFrEF. The evidence reviewed may not apply in the UK because care is delivered differently.