Clinical significance of pain in patients with chronic heart failure.
BACKGROUND
There is a paucity of studies investigating the clinical and biochemical characteristics of pain in chronic heart failure (CHF) patients. This study aimed to determine the clinical and biochemical characteristics and outcomes in Chinese patients with CHF and symptoms of pain.


METHODS
Sociodemographics, serum levels of creatinine, NT-proBNP, high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10, and two-dimensional echocardiographic left ventricular ejection fraction (LVEF) were determined in 305 patients with CHF. A questionnaire packet including the Brief Pain Inventory (BPI) and the Minnesota Living with Heart Failure Questionnaire (MLHFQ) was used to assess the degree of pain rated on a 0 - 10 scale and the quality of life (QOL). A six-minute walking test was performed during routine clinic visits. Major adverse cardiac events (MACE) were recorded; including all-cause or cardiac mortality and rehospitalization because of myocardial infarction, worsening heart failure or stroke at follow-up.


RESULTS
Pain occurred in 25.6% of CHF patients, and was more common when the New York Heart Association (NYHA) functional class was worse. More patients with pain were female in gender, and had more co-morbidities, lower LVEF, and shorter distance during the 6-minute walking test. Despite similar serum levels of creatinine, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), IL-6 and IL-10, the TNF-α levels were higher and MLHFQ scores were greater in CHF patients with pain. At follow-up, CHF patients with moderate to severe pain (≥ 4 scale) had higher rates of all-cause and cardiac mortality and rehospitalization because of myocardial infarction, worsening heart failure or stroke. Multivariate regression analysis revealed that the presence of pain was an independent risk factor for MACE and reduced QOL in CHF patients.


CONCLUSIONS
Pain occurs in all stages of the CHF trajectory, and its incidence increases as clinical functional status is worsened. The presence of pain exerts a negative impact on clinical outcome and QOL in patients with CHF.