Identification and guided treatment of ventricular dysfunction in general practice using blood B-type natriuretic peptide

Long-term monitoring in primary care for chronic kidney disease and chronic heart failure: a multi-method research programme

Background

Long-term monitoring is important in chronic condition management. Despite considerable costs of monitoring, there is no or poor evidence on how, what and when to monitor. The aim of this study was to improve understanding, methods, evidence base and practice of clinical monitoring in primary care, focusing on two areas: chronic kidney disease and chronic heart failure.

Objectives

The research questions were as follows: does the choice of test affect better care while being affordable to the NHS? Can the number of tests used to manage individuals with early-stage kidney disease, and hence the costs, be reduced? Is it possible to monitor heart failure using a simple blood test? Can this be done using a rapid test in a general practitioner consultation? Would changes in the management of these conditions be acceptable to patients and carers?

Design

Various study designs were employed, including cohort, feasibility study, Clinical Practice Research Datalink analysis, seven systematic reviews, two qualitative studies, one cost-effectiveness analysis and one cost recommendation.

Setting

This study was set in UK primary care.

Data sources

Data were collected from study participants and sourced from UK general practice and hospital electronic health records, and worldwide literature.

Participants

The participants were NHS patients (Clinical Practice Research Datalink: 4.5 million patients), chronic kidney disease and chronic heart failure patients managed in primary care (including 750 participants in the cohort study) and primary care health professionals.

Interventions

The interventions were monitoring with blood and urine tests (for chronic kidney disease) and monitoring with blood tests and weight measurement (for chronic heart failure).

Main outcome measures

The main outcomes were the frequency, accuracy, utility, acceptability, costs and cost-effectiveness of monitoring.

Results

Chronic kidney disease: serum creatinine testing has increased steadily since 1997, with most results being normal (83% in 2013). Increases in tests of creatinine and proteinuria correspond to their introduction as indicators in the Quality and Outcomes Framework. The Chronic Kidney Disease Epidemiology Collaboration equation had 2.7% greater accuracy (95% confidence interval 1.6% to 3.8%) than the Modification of Diet in Renal Disease equation for estimating glomerular filtration rate. Estimated annual transition rates to the next chronic kidney disease stage are ≈ 2% for people with normal urine albumin, 3–5% for people with microalbuminuria (3–30 mg/mmol) and 3–12% for people with macroalbuminuria (> 30 mg/mmol). Variability in estimated glomerular filtration rate-creatinine leads to misclassification of chronic kidney disease stage in 12–15% of tests in primary care. Glycaemic-control and lipid-modifying drugs are associated with a 6% (95% confidence interval 2% to 10%) and 4% (95% confidence interval 0% to 8%) improvement in renal function, respectively. Neither estimated glomerular filtration rate-creatinine nor estimated glomerular filtration rate-Cystatin C have utility in predicting rate of kidney function change. Patients viewed phrases such as ‘kidney damage’ or ‘kidney failure’ as frightening, and the term ‘chronic’ was misinterpreted as serious. Diagnosis of asymptomatic conditions (chronic kidney disease) was difficult to understand, and primary care professionals often did not use ‘chronic kidney disease’ when managing patients at early stages. General practitioners relied on Clinical Commissioning Group or Quality and Outcomes Framework alerts rather than National Institute for Health and Care Excellence guidance for information. Cost-effectiveness modelling did not demonstrate a tangible benefit of monitoring kidney function to guide preventative treatments, except for individuals with an estimated glomerular filtration rate of 60–90 ml/minute/1.73 m2, aged < 70 years and without cardiovascular disease, where monitoring every 3–4 years to guide cardiovascular prevention may be cost-effective. Chronic heart failure: natriuretic peptide-guided treatment could reduce all-cause mortality by 13% and heart failure admission by 20%. Implementing natriuretic peptide-guided treatment is likely to require predefined protocols, stringent natriuretic peptide targets, relative targets and being located in a specialist heart failure setting. Remote monitoring can reduce all-cause mortality and heart failure hospitalisation, and could improve quality of life. Diagnostic accuracy of point-of-care N-terminal prohormone of B-type natriuretic peptide (sensitivity, 0.99; specificity, 0.60) was better than point-of-care B-type natriuretic peptide (sensitivity, 0.95; specificity, 0.57). Within-person variation estimates for B-type natriuretic peptide and weight were as follows: coefficient of variation, 46% and coefficient of variation, 1.2%, respectively. Point-of-care N-terminal prohormone of B-type natriuretic peptide within-person variability over 12 months was 881 pg/ml (95% confidence interval 380 to 1382 pg/ml), whereas between-person variability was 1972 pg/ml (95% confidence interval 1525 to 2791 pg/ml). For individuals, monitoring provided reassurance; future changes, such as increased testing, would be acceptable. Point-of-care testing in general practice surgeries was perceived positively, reducing waiting time and anxiety. Community heart failure nurses had greater knowledge of National Institute for Health and Care Excellence guidance than general practitioners and practice nurses. Health-care professionals believed that the cost of natriuretic peptide tests in routine monitoring would outweigh potential benefits. The review of cost-effectiveness studies suggests that natriuretic peptide-guided treatment is cost-effective in specialist settings, but with no evidence for its value in primary care settings.

Limitations

No randomised controlled trial evidence was generated. The pathways to the benefit of monitoring chronic kidney disease were unclear.

Conclusions

It is difficult to ascribe quantifiable benefits to monitoring chronic kidney disease, because monitoring is unlikely to change treatment, especially in chronic kidney disease stages G3 and G4. New approaches to monitoring chronic heart failure, such as point-of-care natriuretic peptide tests in general practice, show promise if high within-test variability can be overcome.

Future work

The following future work is recommended: improve general practitioner–patient communication of early-stage renal function decline, and identify strategies to reduce the variability of natriuretic peptide.

Study registration

This study is registered as PROSPERO CRD42015017501, CRD42019134922 and CRD42016046902.

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. 9, No. 10. See the NIHR Journals Library website for further project information.

B-type natriuretic peptide-guided therapy for perioperative medicine?

The recent guideline from the European Society of Cardiology and European Society of Anesthesiology recommended the use of B-type natriuretic peptide (BNP) as preoperative testing for high-risk cardiac patients undergoing non-cardiac surgery. In this article, the potential benefits, risks and details for implementing BNP testing in perioperative medicine are discussed. Review of four related lines of research including the use of BNP test for preoperative prognosis, BNP test for screening asymptomatic heart failure, BNP as prognostic test in asymptomatic, non-heart failure patients and using BNP for detecting silent myocardial ischaemia showed converging cut-off levels of BNP for risk stratification. BNP has better OR and relative risk in comparison with Revised Cardiac Risk Index (RCRI) in predicting perioperative cardiac risk. BNP-guided therapy can be low risk based on current evidence on non-surgical patients, including treating asymptomatic patients without heart failure to prevent cardiovascular complications. At present, there is lack of direct evidence supporting perioperative BNP testing. Further research with randomised controlled trials is needed to confirm the benefit of BNP-guided management. Preoperative BNP testing may be considered in patients with RCRI above 0 undergoing intermediate or high-risk surgery. BNP-guided therapy is likely a beneficial addition to perioperative medicine. Its combination with β-blocker titration, RCRI and perioperative cardiovascular monitoring can be a major advance in reducing cardiac risk resulting in a dynamic, individualised optimisation process.

Monitoring in clinical biochemistry

Monitoring tests form an increasing proportion of the workload in clinical biochemistry and biochemists can help by providing clinicians with information about the variability and precision of tests, the time frame for pharmacodynamic stabilisation after a treatment change, and the frequency of testing. This paper outlines the phases of monitoring, and how to decide if monitoring is beneficial, which test to use for monitoring, when a change in the test result indicates a need for the change in treatment and the length of testing intervals. We conclude with some recommendations for biochemists for future areas of research and advice that can be given to clinicians.

Improved pharmacological therapy of chronic heart failure in primary care: a randomized Study of NT-proBNP Guided Management of Heart Failure--SIGNAL-HF (Swedish Intervention study--Guidelines and NT-proBNP AnaLysis in Heart Failure)

AIMS

Treatment of chronic heart failure (CHF) guided by natriuretic peptides has been studied in clinical trials with conflicting results. The aim of this study was to investigate if N-terminal pro-B-type natriuretic peptide (NT-proBNP)-guided therapy in symptomatic heart failure patients in primary care would improve clinical outcomes over and above treatment according to guidelines.

METHODS AND RESULTS

SIGNAL-HF was a 9 month, randomized, single-blind, parallel group study in patients with CHF in NYHA class II-IV, ejection fraction (EF)<50% and elevated NT-proBNP levels (males>800, females>1000 ng/L). All investigators underwent a pre-study educational programme about current CHF guidelines. A control group managed by non-trained investigators was considered not possible for ethical and practical reasons. Patients were randomized to structured treatment of CHF according to guidelines with or without NT-proBNP monitoring. The choice and dose of therapy for CHF was at the investigator's discretion. The primary outcome variable was the composite endpoint of days alive, days out of hospital, and symptom score from the Kansas City Cardiomyopathy Questionnaire. In all, 252 patients were randomized. The allocation groups were well balanced with regards to age, NT-proBNP, and EF. Treatment doses of beta-blockers and blockers of the renin-angiotensin-aldosterone system were markedly increased towards target doses and to a similar degree in both groups. There were no differences between the groups concerning either the primary endpoint (P=0.28) or its components [cardiovascular (CV) death, P=0.93; CV hospitalization, P=0.88; or symptom score, P=0.28].

CONCLUSION

NT-proBNP-guided CHF treatment did not result in important improvements in clinical outcomes in patients with CHF in primary care above and beyond what could be achieved by education and structured CHF treatment according to guidelines.

Trends and inequities in beta-blocker prescribing for heart failure

BACKGROUND

Treatment with specific beta-blockers reduces mortality and hospitalisation in heart failure.

AIM

To describe trends and inequities in beta-blocker prescribing for heart failure.

DESIGN OF STUDY

Repeated cross-sectional analysis of a nationally representative primary care database (DIN-LINK).

SETTING

A total of 152 UK general practices.

METHOD

Prescribing of beta-blockers between 2000 and 2005 was examined among a yearly average of 7294 patients aged>or=50 years who had actively managed heart failure - defined as a recorded diagnosis of heart failure and two prescriptions of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker during the calendar year. The main outcome was the prescription of a guideline-recommended beta-blocker (bisoprolol, carvedilol, metoprolol, or nebivolol) in the year. Determinants of beta-blocker prescribing were analysed using logistic regression.

RESULTS

Between 2000 and 2005, age-adjusted use of recommended beta-blockers rose from 6.1% to 27.0% in men, and from 4.2% to 21.5% in women. In 2005, younger patients were more likely to be treated; the fully adjusted odds ratio was 4.83 (95% confidence interval=3.78 to 6.17) for patients aged 60-64 years compared with those aged 85 years. Women and patients living in areas of socioeconomic deprivation were less likely to be treated. In 2005, in addition to treatment with guideline-recommended beta-blockers, a further 11.7% of men and 12.5% of women were prescribed other beta-blockers.

CONCLUSION

Recommended beta-blocker use has risen in the UK but remains low and inequitable, with many patients still treated with beta-blockers that are not recommended in guidelines. This suggests further improvements in prescribing are still possible.