Using NT-proBNP as a criterion for heart failure hospitalization

The matched case-control, single-centred, prospective study by Ozturk et al. was designed to compare the NT-proBNP levels between hospitalized congestive heart failure (CHF) patients and outpatients.1 The main purpose of their study was to define a certain cut-off NT-proBNP value for hospitalization of CHF patients. We will address five points to challenge their study design and presentation (As summarized in Figure 1): 1- The small sample size and wide range of NT-proBNP (with wide standard error) in the patient group (range: 245-35,000) may present low analysis power. 2- In order to define a cut point level of NTproBNP, the area under curve (AUC) should be used. 3- According to Table 3 in their article, confounding variables should be defined and analyzed separately. 4- Since mean of NT-proBNP may vary by age, dividing the patients based on age (<50, 50- 75, >75 years) would have been more appropriate. 5- In Table 1, that showed baseline characteristics of patients in their paper, data about outpatients (n = 32) should have been separated according to normal and stabilized heart failure (HF) groups. We also should mention additional comments about using BNP or NT-proBNP in diagnosis of CHF: