Clinically relevant diagnostic research in primary care: the example of B-type natriuretic peptides in the detection of heart failure

Predictive capacity of the brain natriuretic peptide in the screening of heart failure in a high altitude population

BACKGROUND

Heart failure (HF) is growing in importance as a significant cause of disease and mortality. When It is suspected, it can be ruled out if BNP values are below 100 pg/mL. Diagnostic certainty can be obtained if echocardiogram shows reduced ejection fraction, diastolic dysfunction or right-sided heart disease. Physiological changes at high altitude are known to affect BNP values. This study pretends to evaluate BNP values when used for HF diagnosis in Huancayo, Perú, a high altitude population located at 3,250 m above sea level.

METHODS

This is a cross-sectional, diagnostic test type study. A total of 83 medical charts of patients with suspected HF, admitted to the Emergency Room and Internal Medicine Service of Ramiro Prialé Prialé National Hospital, were reviewed. Data processing was performed with SPSS program for Windows version 21.0. Pearson's Chi Square test was used for categorical variables analysis and ANOVA for continuos variables. P values under 0.05 were considered significant.

RESULTS AND CONCLUSIONS

Medium age was 74 years. Patient's characteristics that were associated with confirmed HF and high BNP levels were the following: presence of fatigue, night cough, elevated heart rate, shortness of breath, history of lung fibrosis and decreased oxygen arterial saturation (p < 0.05) Pulmonary hypertension, mitral and tricuspid regurgitation, and cor pulmonale were also associated with higher BNP levels. Most subjects had BNP values >100 pg/mL, with low specificity for HF diagnosis (11.5 %). Individuals without heart failure had mean BNP values above 300 pg/mL; while individuals with cor pulmonale had a mean of 975 pg/mL. BNP values were high in patients with or without HF. A cut-off point of ≥130pg/mL is proposed to increase specificity. The predictive capacity of BNP for HF identification at this high altitude population is low because of a high number of false positive results.

Time trends in the use and appropriateness of natriuretic peptide testing in primary care: an observational study

BACKGROUND

Diagnosing heart failure (HF) is difficult, relying on medical history, symptoms, and signs only. Clinical guidelines recommend natriuretic peptides (NPs) as an additional diagnostic test, notably to exclude HF in suspected patients. NP testing has been available since 2003 for primary care in the Netherlands, but little is known about its uptake.

AIM

To evaluate the trend in ordering and appropriateness of NP testing in primary care.

DESIGN & SETTING

An observational study was performed between January 2005 and December 2013. Nine Dutch general practices participated, with 21 000 registered people (approximately 4300 aged ≥65 years).

METHOD

The total number of patients undergoing NP testing each year was calculated per 1000 patient years (PY) based on the total practice population. NP levels were used to assess whether NP testing was applied to exclude or confirm HF.

RESULTS

The number of NP testing increased from 2.5 per 1000 PY in 2005 to 14.0 per 1000 PY in 2013, with a peak in 2009 of 15.6 per 1000 PY. The proportion of participants with N-terminal B-type natriuretic peptide (NTproBNP) below 125 pg/ml (the exclusionary threshold recommended by the European Society of Cardiology [ESC] guidelines on HF) was on average 30%, and highest in the first year (47%).

CONCLUSION

After a rapid uptake of NP testing in primary care from 2005 onwards, the use of it seemed to stabilise after 2009, thus leaving patients who are prone to HF without an optimal diagnostic work-up.

Correlation between brain natriuretic peptide levels and the prognosis of patients with left ventricular diastolic dysfunction

The present study aimed to investigate the association between brain natriuretic peptide (BNP) levels and the prognosis of patients with left ventricular (LV) diastolic dysfunction. A total of 708 inpatients with cardiovascular disease (mean age, 66 years; 395 males and 313 females) were grouped according to initial BNP and were followed-up for 20-51 months (average, 30.86 months) until endpoint events occurred. Endpoints were defined as mortality or readmission due to cardiovascular disease, or mortality due to any other reason. A total of 67 and 77 events were reported in the BNP ≤80 pg/ml and BNP >80 pg/ml groups, respectively. The occurrence rate of the endpoint was significantly higher in the BNP >80 pg/ml group, as compared with the BNP ≤80 pg/ml group (26.28 vs. 16.14%; relative risk=1.63). Furthermore, the durations of patient survival were significantly shorter in the BNP >80 pg/ml group, as compared with the BNP ≤80 pg/ml group (P=0.0006), and patient survival decreased as BNP levels rose (P=0.0074). Among the 708 patients, 677 underwent echocardiographic detection at the same time. No significant correlation was detected between BNP levels and survival time in 178 patients with normal LV diastolic function [mitral Doppler flow, early diastolic (E)/late diastolic (A)>1] (P=0.2165); whereas a negative correlation was determined in 499 patients with LVD dysfunction (E/A≤1) (Spearman's rho=-0.0899; P=0.0447). The prognoses of patients with elevated BNP levels were correspondingly worse in the present study and these correlations were demonstrated to be significant in patients with LV diastolic dysfunction. Therefore, BNP levels may be used to predict the prognosis of patients with cardiovascular disease.

Prognostic value of brain natriuretic peptide in patients with heart failure and reserved left ventricular systolic function

Brain natriuretic peptide (BNP) is used as a prognostic biomarker for patients with heart failure (HF) in clinical practice, however, the correlation between BNP levels and the prognosis of HF in patients with reserved left ventricular systolic function (RLVSF) is not clear. Thus, the aim of the present study was to evaluate the added value of BNP in the prognosis of HF patients with RLVSF. Inpatients with cardiovascular disease (mean age, 65.7 years; male, 790; female, 625) admitted to the Division of Cardiology at Jinshan Hospital of Fudan University (Shanghai, China) between June 2006 and December 2009 underwent follow-up examinations. Plasma BNP levels were analyzed and measurements of the left ventricular ejection fraction (LVEF) were performed by echocardiography. Evaluations of the patients with HF were performed according to the New York Heart Association (NYHA) classification system. The duration of the follow-up period ranged between 21 and 63 months (average duration, 35.8 months) and key events included cardiovascular mortality, readmission due to cardiovascular disease or mortality due to other reasons. Survival times decreased with increasing BNP levels in all the follow-up patients (Spearman's ρ, -0.1877; P<0.0001). Among the 1,415 patients, 1,312 underwent echocardiographic detection. A total of 395 patients with NYHA classes II-IV and a LVEF ≥45% were selected. The incidence of compound endpoint events was significantly higher in the patients that had BNP levels of >100 pg/ml when compared with the patients that had BNP levels of ≤100 pg/ml (37.07 vs. 23.93%; relative risk, 1.55); consequently the survival times were significantly reduced (P=0.0039). A negative correlation was identified between the BNP levels and the survival times in these patients (Spearman's ρ, -0.1738; P=0.0005). These results indicated that the levels of BNP may be used to predict the prognosis of patients with cardiovascular disease. The prognoses of patients with higher BNP levels were worse compared with the patients with lower BNP levels. Furthermore, significant correlations were confirmed in the HF patients with RLVSF.

Detecting depressive and anxiety disorders in distressed patients in primary care; comparative diagnostic accuracy of the Four-Dimensional Symptom Questionnaire (4DSQ) and the Hospital Anxiety and Depression Scale (HADS)

Background

Depressive and anxiety disorders often go unrecognized in distressed primary care patients, despite the overtly psychosocial nature of their demand for help. This is especially problematic in more severe disorders needing specific treatment (e.g. antidepressant pharmacotherapy or specialized cognitive behavioural therapy). The use of a screening tool to detect (more severe) depressive and anxiety disorders may be useful not to overlook such disorders. We examined the accuracy with which the Four-Dimensional Symptom Questionnaire (4DSQ) and the Hospital Anxiety and Depression Scale (HADS) are able to detect (more severe) depressive and anxiety disorders in distressed patients, and which cut-off points should be used.

Methods

Seventy general practitioners (GPs) included 295 patients on sick leave due to psychological problems. They excluded patients with recognized depressive or anxiety disorders. Patients completed the 4DSQ and HADS. Standardized diagnoses of DSM-IV defined depressive and anxiety disorders were established with the Composite International Diagnostic Interview (CIDI). Receiver Operating Characteristic (ROC) analyses were performed to obtain sensitivity and specificity values for a range of scores, and area under the curve (AUC) values as a measure of diagnostic accuracy.

Results

With respect to the detection of any depressive or anxiety disorder (180 patients, 61%), the 4DSQ and HADS scales yielded comparable results with AUC values between 0.745 and 0.815. Also with respect to the detection of moderate or severe depressive disorder, the 4DSQ and HADS depression scales performed comparably (AUC 0.780 and 0.739, p 0.165). With respect to the detection of panic disorder, agoraphobia and social phobia, the 4DSQ anxiety scale performed significantly better than the HADS anxiety scale (AUC 0.852 versus 0.757, p 0.001). The recommended cut-off points of both HADS scales appeared to be too low while those of the 4DSQ anxiety scale appeared to be too high.

Conclusion

In general practice patients on sick leave because of psychological problems, the 4DSQ and the HADS are equally able to detect depressive and anxiety disorders. However, for the detection of cases severe enough to warrant specific treatment, the 4DSQ may have some advantages over the HADS, specifically for the detection of panic disorder, agoraphobia and social phobia.