RESUMO
BACKGROUND: While the prognostic value of six-minute walking test (6MWT) in patients with heart failure (HF) and reduced ejection fraction has been firmly established, there are few or no data correlating the distance walked during 6MWT (6MWD) with mortality in patients with HF with preserved ejection fraction (HFpEF) METHODS: We studied 482 patients with HFpEF who had been admitted to inpatients cardiac rehabilitation. The primary outcome was 3-year all-cause mortality. The association between 6MWD and the primary outcome was assessed using multivariable models. Established risk markers were incorporated into the models. RESULTS: 174 patients died during the 3-year follow-up. Taking the highest tertile of 6MWD (≥360 m) as reference, the adjusted hazard ratio (HR) of the primary outcome was 2.23 (95 % CI 1.31-3.78; p = .003) for the patients in the intermediate tertile (241-359 m) and 4.94 (95 % CI 2.90-8.39; p < .001) for those in the lowest tertile (≤240 m). The annual mortality rate was 25.0 % in the lowest tertile, 10.9 % in the intermediate tertile, and 5.3 % in the highest tertile. When the distance walked was normalized for age, sex, and body mass index and expressed as percent-of-predicted walking distance, the adjusted HR was 1.30 (95 % CI 0.76-2.22; p = .331) for the patients in the intermediate tertile (58.2 % to 77.6 %) and 3.52 (95 % CI 2.12-5.85; p < .001) for those in the lowest tertile (≤58.1 %). CONCLUSIONS: Our findings suggest that measuring functional capacity by evaluating the distance that a patient can walk over a period of 6 min provides important prognostic information in HFpEF.
RESUMO
Natriuretic peptides (NP) are recognized as the most powerful predictors of adverse outcomes in heart failure (HF). We hypothesized that a measure of functional limitation, as assessed by 6-min walking test (6MWT), would improve the accuracy of a prognostic model incorporating a NP. This was a multicenter observational retrospective study. We studied the prognostic value of severe functional impairment (SFI), defined as the inability to perform a 6MWT or a distance walked during a 6MWT < 300 m, in 1696 patients with HF admitted to cardiac rehabilitation. The primary outcome was 1-year all-cause mortality. After adjusting for the baseline multivariable risk model-including age, sex, systolic blood pressure, anemia, renal dysfunction, sodium level, and NT-proBNP-or for the MAGGIC score, SFI had an odds ratio of 2.58 (95% CI 1.72-3.88; p < 0.001) and 3.12 (95% CI 2.16-4.52; p < 0.001), respectively. Adding SFI to the baseline risk model or the MAGGIC score yielded a significant improvement in discrimination and risk classification. Our data suggest that a simple, 6MWT-derived measure of SFI is a strong predictor of death and provide incremental prognostic information over well-established risk markers in HF, including NP, and the MAGGIC score.