Diagnostic Equivalence of an N-terminal Pro-Brain Natriuretic Peptide Point-of-Care Test to the Laboratory Method in Patients With Heart Failure and in Reference Populations

Research on point-of-care tests in outpatient care in Germany: A scoping review and definition of relevant endpoints in evaluation studies

BACKGROUND

The fast turnaround time and user-friendliness of point-of-care tests (POCTs) offer a great potential to improve outpatient health care where clinical decisions have to be made during the physician-patient encounter and time resources are limited. The aim of this scoping review is to describe the extent and nature as well as gaps in German research activities on POCT in outpatient care. In addition, we define research endpoints that should be addressed in the comprehensive evaluation of POCTs targeted for outpatient care.

METHODS

We performed a scoping review with a systematic literature search in Medline (via PubMed), Scopus, Web of Science, Cochrane library and Google Scholar for German publications on POCT with relevance to German outpatient care published from January 2005 to November 2020.

RESULTS

Our literature search identified 2,200 unique records. After literature selection 117 articles were included in this scoping review. Just over half of the articles (67/117, 57.3%) were primary research studies with original data, while one third of all the studies (33.3%) were secondary research articles (e.g., review articles). The remaining articles were clinical recommendations / position papers (7/117, 6.0%) and other types of articles (3.4%). The majority of articles focused on POCT use in infectious diseases (44/117, 37.6%), diabetic syndromes (15.4%), cardiac disease (12.0%) or coagulopathies and thrombosis (10.3%), while the remaining articles did not specify the disease (13.7%) or investigated other diseases (11.1%). Similar to international studies, most primary research studies investigated the diagnostic performance of POCT (e.g., sensitivity, specificity). Evidence beyond diagnostic accuracy remains scarce, such as the impact on therapeutic decisions and practice routines, clinical effectiveness, and user perspectives. In line with this, interventional studies (such as RCTs) on the effectiveness of POCT use in German outpatient care are limited. We define six endpoint domains that should be addressed in the evaluation of POCTs targeted for outpatient care: (i) diagnostic performance, (ii) clinical performance, (iii) time and costs, (iv) impact on clinical routines / processes, (v) perspectives of medical professionals and patients, and (vi) broader aspects.

CONCLUSION

There is considerable research activity on POCTs targeted for use in outpatient care in Germany. Data on their potential benefits beyond diagnostic accuracy is often lacking and should be addressed in future POCT research studies.

Diagnosing heart failure in primary care: individual patient data meta-analysis of two European prospective studies

Aims

Natriuretic peptides are helpful in detecting chronic heart failure (HF) in primary care; however, there are a lack of data evaluating thresholds recommended by clinical guidelines. This study assesses the diagnostic accuracy of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) using combined individual patient data from two studies in the UK and the Netherlands.

Methods and results

Random effects methods were used to estimate the performance characteristics of NT‐proBNP thresholds recommended by the European Society of Cardiology (ESC) and the UK National Institute for Health and Care Excellence (NICE) guidelines. New onset HF was diagnosed in 313 of 1073 (29.2%) participants. Age, sex, and atrial fibrillation‐adjusted NT‐proBNP was a better predictor of HF with reduced ejection fraction (HFrEF) than HF preserved ejection fraction (HFpEF), with area under receiver operating characteristic curve of 0.82 95% CI (0.78 to 0.86) vs. 0.71 (0.66 to 0.75). In persons aged 70 years and over, the ESC threshold at 125 ng/L for detection of all‐cause HF had summary negative predictive value (NPV) of 84.9% (81.6 to 88.2), positive predictive value (PPV) 68.1% (63.1 to 73.3), sensitivity 74.9% (69.5 to 80.3), and specificity 80.1% (76.9 to 83.4); the NICE threshold at 400 ng/L had summary NPV of 74.7% (72.1 to 77.2), PPV 81.8% (73.3 to 89.5), sensitivity 43.5% (37.2 to 49.8), and specificity 94.5% (92.3 to 96.7).

Conclusions

N‐terminal pro‐B‐type natriuretic peptide is better at detecting HFrEF than HFpEF in a primary care setting. In persons aged 70 and over, the ESC threshold of 125 ng/L is more accurate at detecting and excluding HF than the higher level suggested in NICE guidelines. More prospective data are required to establish the optimal NP threshold for detecting chronic HF in general practice.

Diagnosing heart failure with NT-proBNP point-of-care testing: lower costs and better outcomes. A decision analytic study

Background

Afflicting 1-2% of the adult population, heart failure (HF) is a condition with considerable morbidity and mortality. While echocardiography may be considered the gold standard diagnostic test, GPs have relied on symptoms and clinical findings in diagnosing the condition.

Aim

The aim of this study was to estimate 1-year health outcome and costs of three diagnostic strategies: 1) history and clinical findings ('clinical diagnosis'); 2) clinical diagnosis supplemented with NTproBNP point-of-care test ('POC test') in the GP's surgery; or (3) in hospital laboratory ('hospital test').

Design & setting

A decision tree model was developed to simulate 1-year patient courses with each strategy in Norway.

Method

Sensitivity and specificity of clinical diagnosis (56% and 68%), and of N-terminal pro B-type natriuretic peptide test ([NT-proBNP] 90% and 65%), were based on published literature. The probabilities of referral to hospital were based on a survey of Norwegian GPs (n = 103). The costs were based on various Norwegian fee schedules. Sensitivity analyses were conducted to examine the uncertainty of the results.

Results

The 1-year per person societal costs were €543, €505, and €607 for clinical diagnosis, POC test, and hospital test, respectively. Even though POC entails higher laboratory costs, the total primary care costs were lower because of fewer re-visits with the GP and less use of spirometry. While 38% of patients had a delayed diagnosis with clinical diagnosis, the proportions were 22% with both POC test and hospital test. Results were most sensitive to the probability of use of spirometry.

Conclusion

POC testing results in earlier diagnosis and lower costs than the other diagnostic modalities.

Equal performance of novel N-terminal proBNP (Cardiac proBNP®) and established BNP (Triage BNP®) point-of-care tests

Background: Recently, a novel point-of-care test (POCT) for N-terminal proBNP (NTproBNP) has been introduced (Cardiac proBNP®, Roche). Aim: The aim was to compare the novel POCT for NTproBNP with the established POCT for BNP. Methods: NTproBNP and BNP were assessed in 222 individuals with chronic heart failure (n = 151) or controls (n = 71) with both POCTs. Results: NTproBNP and BNP were closely correlated upon regression analysis (r = 0.93; p < 0.01). NTproBNP and BNP were both correlated with ejection fraction and New York Heart Association stage. Receiver operating characteristic analysis yielded satisfying and equivalent predictive values for the detection of left ventricular dysfunction (ejection fraction <40%; NTproBNP: area under the curve 0.97; BNP: area under the curve 0.96; p > 0.05) and presence of New York Heart Association stage >2 (area under the curve 0.92 vs 0.91 for NT-proBNP and BNP, respectively; p > 0.05). Conclusion: The NTproBNP POCT allows biochemical detection of heart failure with satisfactory predictive values, is equivalent to the BNP POCT and will improve near-patient testing.