Page 131 - Biomarkers for risk stratification and guidance in heart failure

Chapter 6
METHODS
Study design and population
This is a post-hoc analysis of patients included in the PRIMA study, a prospective randomized multicenter study assessing the effect of management of chronic heart failure guided by individual NT-proBNP targets.12 Inclusion- and exclusion criteria have been published previously.12 In short, patients were included during hospital admission for acute HF. NT-proBNP concentration on admission was required to be at least 1,700 pg/ml and patients included also needed to demonstrate a minimum decrease in NT-proBNP concentration of 10% with a minimum of 850 pg/ml during admission. At discharge, patients were randomized to outpatient treatment that was either clinically-guided where NT-proBNP was measured but not revealed to the physician, or to outpatient treatment that was clinically-guided but where additionally NT-proBNP levels were provided to guide therapy. The follow-up period was up to 2 years.
For this sub analysis, we included patients with creatinine and NT-proBNP measurements available at discharge and the follow-up visit 1 month after hospital discharge. Patients were divided into four groups based on change in estimated glomerular filtration rate (eGFR) and NT-proBNP concentration during the first month post-discharge:
Group 1. Decrease in NT-proBNP in combination with an increase in eGFR Group 2. Decrease in NT-proBNP in combination with a decrease in eGFR Group 3. Increase in NT-proBNP in combination with an increase in eGFR Group 4. Increase in NT-proBNP in combination with a decrease in eGFR
Definition of study endpoints
Primary outcome measure was the combined endpoint of HF readmission or mortality within one year follow-up. Secondary endpoints encompassed one year mortality, and all endpoints at 90 and 180 days of follow-up.
Statistical analysis
Data are presented as frequencies, mean ±SD or median (interquartile range, IQR). Comparisons between groups were performed using Fischer´s exact test for categorical data and one-way ANOVA or Kruskal-Wallis H test for continuous data, as appropriate. If baseline characteristics differed significantly among the 4 groups
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