Brief Article Open Access
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Cardiol. Aug 26, 2012; 4(8): 250-255
Published online Aug 26, 2012. doi: 10.4330/wjc.v4.i8.250
Evaluation of the prevalence and severity of pain in patients with stable chronic heart failure
Dioma U Udeoji, Ernst R Schwarz, Peter Katsiyianis, Heart Institute of Southern California, Temecula, CA 92592, United State
Dioma U Udeoji, Ankit B Shah, Parag Bharadwaj, Ernst R Schwarz, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States
Parag Bharadwaj, Ernst R Schwarz, University of California Los Angeles, Los Angeles, CA 90095, United States
Author contributions: Udeoji DU designed the study, acquired data, statistically analyzed, and interpreted data, drafted the article, wrote the manuscript and critically revised the manuscript; Shah AB supported the work and made contributions, analyzed data, interpreted data and reviewed the manuscript; Bharadwaj P was a co-investigator and part of the administration, gave supportive contributions, technology and material support, participated in the study design and manuscript review; Katsiyiannis P was part of the administration, gave supportive contributions, technology and material support; Schwarz ER was the principal Investigator and part of the administration, gave supportive work/ contributions, technology and material support, participated in the study design, manuscript writing, critical revision of the manuscript and general supervision of the work.
Correspondence to: Ernst R Schwarz, MD, PHD, FACC, FSCAI, FESC, Heart Institute of Southern California, 31720 Temecula Parkway, Ste. 200, Temecula, CA 92592, United States. ernst.schwarz@cshs.org
Telephone: 1-951-3020606 Fax: +1-951-2497277
Received: July 5, 2012
Revised: August 20, 2012
Accepted: August 24, 2012
Published online: August 26, 2012

Abstract

AIM: To evaluate the prevalence and severity of pain in patients with chronic stable heart failure (HF) in an outpatient clinic setting.

METHODS: This is a cross-sectional study evaluating symptoms of generalized or specific pain in patients with chronic stable heart failure. A standardized questionnaire (Edmonton Symptom Assessment System) was administered during a routine outpatient clinic visit. The severity of pain and other symptoms were assessed on a 10 point scale with 10 being the worst and 0 representing no symptoms.

RESULTS: Sixty-two patients [age 56 ± 13 years, 51 males, 11 females, mean ejection fraction (EF) 33% ± 17%] completed the assessment. Thirty-two patients (52%) reported any pain of various character and location such as chest, back, abdomen or the extremities, with a mean pain score of 2.5 ± 3.1. Patients with an EF less than 40% (n = 45, 73%) reported higher pain scores than patients with an EF greater than 40% (n = 17, 27%), scores were 3.1 ± 3.3 vs 1.2 ± 1.9, P < 0.001. Most frequent symptoms were tiredness (in 75% of patients), decreased wellbeing (84%), shortness of breath (SOB, 76%), and drowsiness (70%). The most severe symptom was tiredness with a score of 4.0 ± 2.8, followed by decreased wellbeing (3.7 ± 2.7), SOB (3.6 ± 2.8), and drowsiness (2.8 ± 2.8).

CONCLUSION: Pain appears to be prevalent and significantly affects quality of life in HF patients. Adequate pain assessment and management should be an integral part of chronic heart failure management.

Key Words: Heart failure; Pain; Symptoms; Therapy; Palliative care



INTRODUCTION

Heart failure is one of the major health problems worldwide especially for people over the age of 65 years[1,2]. In the United States, more than 38 million people suffer from heart diseases. Almost six million patients are diagnosed with heart failure (HF) with more than 550  000 newly diagnosed cases each year[1,3,4]. HF accounts for 12-15 million office visits per year and over six million hospital admissions in the United States[1,4]. HF usually is a chronic illness that might involve multiple organs systems over time leading to a variety of non-organ-specific symptomatology.

The burden of pain is under-recognized by clinicians as a symptom among heart failure patients. Only few studies have demonstrated an association between pain and heart failure. Evidence demonstrated that HF is a gradual disease process, which is initiated with risk factors, often triggered by an acute event, and progresses to changes in cardiac structure to loss of function that subsequently results in clinically overt HF with functional decline, and death[5-10].

The present study was designed to evaluate the prevalence and severity of generalized symptoms and pain in adult patients with stable chronic HF.

MATERIALS AND METHODS

This is a cross-sectional study of symptom assessment in patients with an established diagnosis of chronic HF. Patients were recruited to participate in the study during a routine outpatient clinic visit between May and December of 2011. The study was approved by the institutional review board. Patients were enrolled after obtaining informed consent.

Inclusion criteria were as follows: (1) age 18 years or older; (2) a primary diagnosis of chronic HF since at least three months; (3) systolic dysfunction; (4) on a stable medication and treatment regimen; and (5) ability to read and understand the English language and respond properly.

Exclusion criteria were (1) unstable patients in new york heart association (NYHA) class IV; (2) patients with concomitant diagnoses that might cause pain or significantly affect quality of life and other symptomatic conditions such as severe chronic obstructive pulmonary disease, diabetes mellitus with end-organ damage, severe liver or kidney failure, active myocardial ischemia, angina pectoris, active or recent malignancies, recent or debilitating strokes, fibromyalgia or other debilitating acute or chronic illnesses; (3) chronic/daily analgesic use for any specific or non- specific non HF-related reasons; and (4) patients with past medical history of cerebral infarction.

All patients were evaluated using a brief cognitive screening test, the “Mini cog”[11-14]. This test is a 5-point cognitive screening which consists of a three different word recall (score 0-3) and a clock drawing with the hand pointing at a specific time (score 0, or 2). Patients with a Mini-cog score of more than three, which rules out dementia were included into the study[11-14]. The study was conducted by a healthcare professional who was not directly involved in the patients’ care. A standardized questionnaire, the Edmonton Symptom Assessment System (ESAS)[15-17] was used to evaluate for symptoms and severity by using a scoring system. The ESAS scoring scale ranges from 0 to 10 with 0 representing no symptoms and 10 representing worst possible symptoms. The presence and severity of the following nine subjective complaints were assessed: pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, wellbeing, and shortness of breath. A diagram of the human body enabled the patient to mark the site of existing pain sensations. The functional status of HF was assessed using both history and physical examination and only patients in NYHA classes II and III were enrolled in the study. Ejection fraction (EF) was measured by 2-D transthoracic echocardiography using the Simpson method either at the time of the visit or echocardiographic data from former visits was used as long as the echo study was performed within six months prior to the beginning of the study. The patients were on a standard regimen containing the following medications: beta blockers (82% of the patients), ACE-inhibitors (44%), angiotensin II receptor blocker (29%), aldosterone antagonists (40%), other diuretics (66%) and digoxin (29%). All patients were on a stable medication regimen without major medication changes except dose adjustments within the last three months. For further analysis, the patients were then divided into two groups: group 1 represented patients with an EF of more than 40%, group 2 represented patients with an EF of less than or equal to 40%. Data between the groups were compared using a student t-test. A P value of less than 0.05 was considered statistically significant.

RESULTS

Sixty-two patients were enrolled in the study, 51 men, 11 women, age 56 ± 13 years (range 28-77 years). The EF was 33% ± 17% (range 10%-76%). The total pain score was 2.5% ± 3.1. 32% reported pain in more than one anatomical site, 15% reported pain either in the chest, back, neck, abdominal or in the extremities. Four patients (7%) did not indicate the site of pain but reported generalized body pain. Patients suffered different co-morbidities irrespective of the EF. The most common co-morbidities were hypertension (n = 38, 61%), hyperlipidemia (n = 29, 47%), end stage renal disease (n = 20, 32%), and diabetes (n = 17, 27%). Other common conditions were atrial fibrillation (28%), depression (18%), obesity (16%), osteoarthritis (15%), COPD (8%), gout (8%), thyroid diseases (7%), anemia (7%) and peripheral artery disease (PAD, 3%). Patients reported pain regardless of the EF and co-morbidities. Patients with degenerative joint diseases reported higher pain scores.

Most frequently reported symptoms were tiredness (n = 47, 76%), decreased wellbeing (n = 52, 84%), shortness of breath (SOB, n = 47, 76%), and drowsiness (n = 43, 69%). The most severe symptoms based on the score were tiredness (score 4.0 ± 2.8), decreased wellbeing (3.7 ± 2.7), SOB (3.6 ± 2.8), and drowsiness (2.8 ± 2.8).

Seventeen patients had an EF > 40% (group 1), 11 (65%) males and 6 (35%) females, age 54 ± 14 years (range 32-74 years), forty-five patients had an EF ≤ 40% (group 2), 40 (89%) males and 5 (11%) females, age 57 ± 13 (range 30-77) years. EFs were 56% ± 11% (range 43%-76%) in group 1 and 24% ± 10% (range 10%-40%) in group 2. Pain score in group 1 was 1.2 ± 1.9, pain score in group 2 was 3.1 ± 3.3 (P < 0.001 between the groups, Table 1).

Table 1 Patients symptoms.
Patients symptomsAll patientsEF > 40%EF40%P value
Pain2.5 ± 3.11.2 ± 1.93.1 ± 3.30.001
Tiredness4.0 ± 2.83.7 ± 2.84.2 ± 2.90.276
Nausea1.2 ± 2.31.2 ± 2.41.2 ± 2.30.497
Depression2.5 ± 3.01.8 ± 2.62.7 ± 3.20.126
Anxiety2.2 ± 2.51.7 ± 2.32.4 ± 2.60.143
Drowsiness2.8 ± 2.82.1 ± 2.63.0 ± 2.90.116
Appetite2.7 ± 3.02.5 ± 3.12.7 ± 2.90.396
Wellbeing3.7 ± 2.72.7 ± 2.54.1 ± 2.60.025
Shortness of breath3.6 ± 2.82.7 ± 2.94.1 ± 2.70.052
Other problems from co morbidities2.1 ± 3.11.7 ± 2.82.3 ± 3.30.296

Pain was present in both groups regardless of co-morbidities. Thirty-two patients (52%) reported pain of various intensities at various locations with pain scores of 2.5 ± 3.1.

DISCUSSION

We evaluated the prevalence and severity of pain in patients with chronic stable heart failure. Fifty-two percent (n = 32) of the patients reported presence of pain of various characters and intensities ranging from a scale of 1-10 at different anatomical sites, or generalized pain. Patients reported pain regardless of the EF and co-morbidities. Patients with degenerative joint diseases reported higher pain scores. The prevalence and severity of pain were higher in patients with a lower EF (≤ 40%).

Pain in HF can be secondary to physical, spiritual, psychological and social factors[4]. Physical pain experienced by patients can be caused by multiple co-morbidities[4,18]. The International Association for the Study of Pain defines pain as an unpleasant sensory or emotional feeling that is associated with potential or actual tissue damage[19]. Pain is present in many medical conditions and it is the most common reason for clinician’s consultation in the United States[20,21].

Pain that is transient, lasting only until the stimulus is removed or the pathology is healed is regarded as acute while pain that persist for years in conditions like cancer, rheumatoid arthritis, peripheral neuropathy and idiopathic type of pain is regarded as chronic. Some authors define acute pain as pain lasting less than one month while others define acute pain as pain that is less than three months from the time of onset. Chronic pain is defined by some as pain lasting up to six months from the onset or a subjective feeling that extends beyond the expected period of healing. Pain lasting between the intervals of 1 mo to 6 mo is regarded to be subacute.

The presence or absence of psychological and social factors can affect the intensity of pain feeling. Some studies showed that patients with psychological issues, anxiety and/or depression reported higher pain score[4,22-25]. Patients who experience severe symptoms such as SOB and fatigue that interfere with daily activities often also complain of pain, which easily can lead to more suffering and even social isolation[4,19].

According to Woolf, there are three classes of pain: nociceptive pain, pathological pain and inflammatory pain[26]. Others types of pain are phantom, incident, psychogenic and breakthrough pain.

Nociceptive pain is caused by noxious stimulation of sensory receptors that responds to potentially damaging stimuli. The stimuli can be from thermal, mechanical or chemical injury. Nociceptive pain can be superficial, somatic or visceral. Superficial pain is caused by activation of nociceptors in the skin or other superficial tissue. It is sharp and well-defined e.g., first degree burns and minor wounds. Somatic pain is initiated by stimulation of nociceptors in body surface or musculoskeletal tissues such as the tendons, ligaments, bones, muscles, fasciae, and blood vessels. Such pain is aching, dull and poorly localized pain. It is aggravated by exertion and relieved by rest. Examples include post surgical pain from surgical incisions, broken bones and sprains. Visceral pain is pain (from the visceral organs) due to stretch, ischemia and inflammation. It is diffuse, vague and difficult to locate. It is described as deep squeezing, pressure like, dull or diffuse type of pain which can be associated with malaise, nausea, vomiting or fever.

Pathological pain is a disease state caused by damage to the nervous system e.g., neuropathic pain or by its abnormal function e.g., fibromyalgia, tension headache and irritable bowel syndrome[26].

Neuropathic pain is caused by disease, injury or malfunction to any part of the nervous system- the central and the peripheral[27]. It may be associated with abnormal sensations (dysesthesia) or pain from normal non-painful stimuli (allodynia). Neuropathic pain is typically burning, shooting, cutting, drilling, stabbing, piercing, itching, stinging, tingling or it may be felt like a coldness, numbness, “pins and needles” or “electric shock” like type of sensation[28]. The pain occur at the level or below the level of injury within days, weeks, or months of the injury. Neuropathic pain can be episodic and/or continuous in nature. It is divided into three types: (1) the central neuropathic pain involving the brain and spinal cord; (2) the peripheral neuropathic pain involving the peripheral nervous system and (3) the mixed neuropathic pain involving both the central and the peripheral nervous system.

Inflammatory pain is a type of pain that is associated with infiltration of immune cells due to cellular or tissue damage[26].

Psychogenic pain or somatoform pain is pain caused by or increased by a mental, an emotional, or a behavioral factor(s). Such pain can manifest as headache, stomach pain and back pain etc.

Phantom pain is a type of pain that result from a part of the body that was surgically or accidentally removed or from which the brain no longer receives signals. This type of pain is mostly reported by amputees.

Breakthrough pain is pain that spontaneously comes on just for short periods of time in patients with a background level of pain and is usually not relieved by the patients’ regular pain medication. The character of this breakthrough pain differs from person to person and according to the cause of the pain. This pain type is commonly seen in cancer patients.

Incident pain is type of pain that arises secondary to exertion e.g., stretching a wound, movement of an arthritic joint etc.

There is limited data on pain association with chronic heart failure. It has been a priority for physicians to manage pain in chronically ill patient but it is rare for physicians to assess or recognize pain as being a symptom in patients with HF. The presence of pain in chronic heart failure patients are insidious and unnoticed[7]. Few studies demonstrated the association of pain with heart failure. A case series using a retrospective review of fifty patients with chronic heart failure for a period of three and a half year indicated that pain was part of multiple symptoms addressed during their hospital visits[29]. A multicenter, cross-sectional studies of 60 patients with heart failure indicated that more than fifty percent of these patients reported pain, shortness of breath, tiredness, drowsiness or dry mouth[22]. Another study with 1786 chronic heart failure patient who completed questionnaires for symptom assessment of heart failure showed that even though pain is common, pain is not necessarily due to angina even in patients with coronary heart disease[30]. Data obtained from three-hundred patients with chronic HF indicated that sixty-seven percent of the patients reported pain with increment in the prevalence of pain as the functional class worsens[7]. In a study of ninety-six veterans with chronic HF, more than fifty percent reported pain with more than thirty-seven percent rating their pain as moderate to severe[4]. Our study demonstrated that pain was present in more than 50% of the patients which reinforces the evidence that pain is one of the symptoms of chronic HF. The pain sensation in patients with chronic HF might be inflammatory and neuropathic in origin or a combination of different types of pain, however, a concise classification of the pain character in these patients is outside the frame of the present study.

It is imperative for clinicians to recognize pain as part of expected symptoms in patients with HF. Adequate pain management that might involve palliative care providers and multidisciplinary teams might be effective in minimizing sufferings and improve quality of life[4,22,31-35].

This is a cross sectional subjective assessment of symptoms rather than an objective measure. Patients were randomly selected from an outpatient clinic cohort. No additional questionnaires were provided.

This study did not identify the causal mechanisms behind the association of pain and heart failure.

Pain and other non specific symptoms are usually not regarded as typical symptoms in patients with chronic heart failure[4,7]. Evidence supports that more than fifty percent of patients with chronic HF report pain of various characters and intensities. Our data suggest that among other symptoms, pain appears to be prevalent and significantly affects quality of life in heart failure patients. Adequate pain assessment and management should be an integral part of chronic heart failure management. Involving a multidisciplinary team in the management of heart failure can help to address the complex nature of pain and improve the quality of life. Further research to study the causal mechanism of pain association with heart failure is needed.

COMMENTS
Background

Pain is a debilitating symptom and a cause of significant burden in patients with chronic diseases. Despite anecdotal data, only few studies demonstrate the clinical relevance of pain in patients with chronic advanced heart failure.

Research frontiers

Chronic heart failure is of growing incidence and prevalence and is now the main cause for hospital admission among the elderly and increasing expenditure in medicine. The evaluation and treatment of patients with chronic heart failure (HF) needs to go beyond cardiac dysfunction and requires a holistic approach of the multisystem involvement and non-specific symptomatology of the patients. The assessment and recognition of pain as a result of the involvement of the entire body system is of enormous clinical relevance.

Innovations and breakthroughs

The data show that pain is a prevalent symptom in patients with chronic HF and can present either as localized or generalized pain. Pain significantly impairs quality of life and often is a leading symptom resulting in recurrent physician office visits, emergency department visits, and subsequent hospitalizations. Despite this, pain has never been considered a characteristic symptom of HF.

Applications

Based on the data, a systematic evaluation of non specific, generalized symptoms including localized or generalized pain should be part of a routine assessment in patients with HF. Adequate pain management will help to (1) alleviate symptoms; (2) improve quality of life; (3) increase patient compliance; (4) reduce emergency visits and hospital admissions; (5) reduce overall morbidity; and (6) reduce costs. Even though pain management is not part of the present study, this aspect requires further investigation.

Terminology

Heart failure is a condition that is usually caused by a reduction of the contractile function of the ventricular chambers or an impairment of the relaxation properties of the cardiac chambers.

Peer review

This article retrospectively investigated the prevalence and severity of pain in patients with chronic heart failure. Chest pain is a clinical symptom suggesting myocardial ischemia. The research may include a potential important topic. There are some issues that need to be addressed precisely.

Footnotes

Peer reviewer: Dr. Shinro Matsuo, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8641, Japan

S- Editor Cheng JX L- Editor A E- Editor Zhang DN

References
1.  Hunt SA, Abraham WT, Chin MH, Feldman AM, Francis GS, Ganiats TG, Jessup M, Konstam MA, Mancini DM, Michl K. ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Update the 2001 Guidelines for the Evaluation and Management of Heart Failure): developed in collaboration with the American College of Chest Physicians and the International Society for Heart and Lung Transplantation: endorsed by the Heart Rhythm Society. Circulation. 2005;112:e154-e235.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 293]  [Cited by in F6Publishing: 248]  [Article Influence: 13.1]  [Reference Citation Analysis (0)]
2.  Masoudi FA, Havranek EP, Krumholz HM. The burden of chronic congestive heart failure in older persons: magnitude and implications for policy and research. Heart Fail Rev. 2002;7:9-16.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in F6Publishing: 1]  [Reference Citation Analysis (0)]
3.  Lloyd-Jones D, Adams RJ, Brown TM, Carnethon M, Dai S, De Simone G, Ferguson TB, Ford E, Furie K, Gillespie C. Heart disease and stroke statistics--2010 update: a report from the American Heart Association. Circulation. 2010;121:e46-e215.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 2338]  [Cited by in F6Publishing: 2604]  [Article Influence: 186.0]  [Reference Citation Analysis (0)]
4.  Goebel JR, Doering LV, Shugarman LR, Asch SM, Sherbourne CD, Lanto AB, Evangelista LS, Nyamathi AM, Maliski SL, Lorenz KA. Heart failure: the hidden problem of pain. J Pain Symptom Manage. 2009;38:698-707.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 67]  [Cited by in F6Publishing: 67]  [Article Influence: 4.5]  [Reference Citation Analysis (0)]
5.  Mitani H, Hashimoto H, Isshiki T, Kurokawa S, Ogawa K, Matsumoto K, Miyake F, Yoshino H, Fukuhara S. Health-related quality of life of Japanese patients with chronic heart failure: assessment using the Medical Outcome Study Short Form 36. Circ J. 2003;67:215-220.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 19]  [Cited by in F6Publishing: 19]  [Article Influence: 0.9]  [Reference Citation Analysis (0)]
6.  Cohn JN. Structural basis for heart failure. Ventricular remodeling and its pharmacological inhibition. Circulation. 1995;91:2504-2507.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 207]  [Cited by in F6Publishing: 219]  [Article Influence: 7.6]  [Reference Citation Analysis (0)]
7.  Evangelista LS, Sackett E, Dracup K. Pain and heart failure: unrecognized and untreated. Eur J Cardiovasc Nurs. 2009;8:169-173.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 57]  [Cited by in F6Publishing: 52]  [Article Influence: 3.5]  [Reference Citation Analysis (0)]
8.  Howlett JG. Palliative care in heart failure: addressing the largest care gap. Curr Opin Cardiol. 2011;26:144-148.  [PubMed]  [DOI]  [Cited in This Article: ]
9.  Ammar KA, Jacobsen SJ, Mahoney DW, Kors JA, Redfield MM, Burnett JC, Rodeheffer RJ. Prevalence and prognostic significance of heart failure stages: application of the American College of Cardiology/American Heart Association heart failure staging criteria in the community. Circulation. 2007;115:1563-1570.  [PubMed]  [DOI]  [Cited in This Article: ]
10.  Mann DL. Mechanisms and models in heart failure: A combinatorial approach. Circulation. 1999;100:999-1008.  [PubMed]  [DOI]  [Cited in This Article: ]
11.  Borson S, Scanlan J, Brush M, Vitaliano P, Dokmak A. The mini-cog: a cognitive 'vital signs' measure for dementia screening in multi-lingual elderly. Int J Geriatr Psychiatry. 2000;15:1021-1027.  [PubMed]  [DOI]  [Cited in This Article: ]
12.  Costa D, Severo M, Fraga S, Barros H. Mini-Cog and Mini-Mental State Examination: agreement in a cross-sectional study with an elderly sample. Dement Geriatr Cogn Disord. 2012;33:118-124.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 18]  [Cited by in F6Publishing: 20]  [Article Influence: 1.7]  [Reference Citation Analysis (0)]
13.  Borson S, Scanlan JM, Chen P, Ganguli M. The Mini-Cog as a screen for dementia: validation in a population-based sample. J Am Geriatr Soc. 2003;51:1451-1454.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 712]  [Cited by in F6Publishing: 773]  [Article Influence: 36.8]  [Reference Citation Analysis (0)]
14.  Milian M, Leiherr AM, Straten G, Müller S, Leyhe T, Eschweiler GW. The Mini-Cog versus the Mini-Mental State Examination and the Clock Drawing Test in daily clinical practice: screening value in a German Memory Clinic. Int Psychogeriatr. 2012;24:766-774.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 39]  [Cited by in F6Publishing: 42]  [Article Influence: 3.5]  [Reference Citation Analysis (0)]
15.  Bruera E, Kuehn N, Miller MJ, Selmser P, Macmillan K. The Edmonton Symptom Assessment System (ESAS): a simple method for the assessment of palliative care patients. J Palliat Care. 1991;7:6-9.  [PubMed]  [DOI]  [Cited in This Article: ]
16.  Moro C, Brunelli C, Miccinesi G, Fallai M, Morino P, Piazza M, Labianca R, Ripamonti C. Edmonton symptom assessment scale: Italian validation in two palliative care settings. Support Care Cancer. 2006;14:30-37.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 144]  [Cited by in F6Publishing: 158]  [Article Influence: 8.3]  [Reference Citation Analysis (0)]
17.  Chang VT, Hwang SS, Feuerman M. Validation of the Edmonton Symptom Assessment Scale. Cancer. 2000;88:2164-2171.  [PubMed]  [DOI]  [Cited in This Article: ]
18.  Goebel JR, Doering LV, Lorenz KA, Maliski SL, Nyamathi AM, Evangelista LS. Caring for special populations: total pain theory in advanced heart failure: applications to research and practice. Nurs Forum. 2009;44:175-185.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 14]  [Cited by in F6Publishing: 14]  [Article Influence: 0.9]  [Reference Citation Analysis (0)]
19.  Bonica JJ. The need of a taxonomy. Pain. 1979;6:247-248.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 237]  [Cited by in F6Publishing: 251]  [Article Influence: 5.6]  [Reference Citation Analysis (0)]
20.  Turk DC, Dworkin RH. What should be the core outcomes in chronic pain clinical trials? Arthritis Res Ther. 2004;6:151-154.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 14]  [Cited by in F6Publishing: 16]  [Article Influence: 0.8]  [Reference Citation Analysis (0)]
21.  Breivik H, Borchgrevink PC, Allen SM, Rosseland LA, Romundstad L, Hals EK, Kvarstein G, Stubhaug A. Assessment of pain. Br J Anaesth. 2008;101:17-24.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 1019]  [Cited by in F6Publishing: 1149]  [Article Influence: 71.8]  [Reference Citation Analysis (0)]
22.  Bekelman DB, Havranek EP, Becker DM, Kutner JS, Peterson PN, Wittstein IS, Gottlieb SH, Yamashita TE, Fairclough DL, Dy SM. Symptoms, depression, and quality of life in patients with heart failure. J Card Fail. 2007;13:643-648.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 211]  [Cited by in F6Publishing: 274]  [Article Influence: 16.1]  [Reference Citation Analysis (0)]
23.  Butler LD, Koopman C, Cordova MJ, Garlan RW, DiMiceli S, Spiegel D. Psychological distress and pain significantly increase before death in metastatic breast cancer patients. Psychosom Med. 2003;65:416-426.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 68]  [Cited by in F6Publishing: 63]  [Article Influence: 3.0]  [Reference Citation Analysis (0)]
24.  Carr EC, Nicky Thomas V, Wilson-Barnet J. Patient experiences of anxiety, depression and acute pain after surgery: a longitudinal perspective. Int J Nurs Stud. 2005;42:521-530.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 92]  [Cited by in F6Publishing: 90]  [Article Influence: 4.5]  [Reference Citation Analysis (0)]
25.  Carels RA, Musher-Eizenman D, Cacciapaglia H, Pérez-Benítez CI, Christie S, O'Brien W. Psychosocial functioning and physical symptoms in heart failure patients: a within-individual approach. J Psychosom Res. 2004;56:95-101.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 41]  [Cited by in F6Publishing: 42]  [Article Influence: 2.1]  [Reference Citation Analysis (0)]
26.  Woolf CJ. What is this thing called pain? J Clin Invest. 2010;120:3742-3744.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in F6Publishing: 1]  [Reference Citation Analysis (0)]
27.  Treede RD, Jensen TS, Campbell JN, Cruccu G, Dostrovsky JO, Griffin JW, Hansson P, Hughes R, Nurmikko T, Serra J. Neuropathic pain: redefinition and a grading system for clinical and research purposes. Neurology. 2008;70:1630-1635.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 1866]  [Cited by in F6Publishing: 1838]  [Article Influence: 108.1]  [Reference Citation Analysis (0)]
28.  Paice JA. Mechanisms and management of neuropathic pain in cancer. J Support Oncol. 2003;1:107-120.  [PubMed]  [DOI]  [Cited in This Article: ]
29.  Bekelman DB, Nowels CT, Allen LA, Shakar S, Kutner JS, Matlock DD. Outpatient palliative care for chronic heart failure: a case series. J Palliat Med. 2011;14:815-821.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 44]  [Cited by in F6Publishing: 47]  [Article Influence: 3.6]  [Reference Citation Analysis (0)]
30.  Clark AL, Goode KM. Do patients with chronic heart failure have chest pain? Int J Cardiol. 2012;Epub ahead of print.  [PubMed]  [DOI]  [Cited in This Article: ]
31.  Bekelman DB, Rumsfeld JS, Havranek EP, Yamashita TE, Hutt E, Gottlieb SH, Dy SM, Kutner JS. Symptom burden, depression, and spiritual well-being: a comparison of heart failure and advanced cancer patients. J Gen Intern Med. 2009;24:592-598.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 193]  [Cited by in F6Publishing: 193]  [Article Influence: 12.9]  [Reference Citation Analysis (0)]
32.  Zambroski CH, Moser DK, Bhat G, Ziegler C. Impact of symptom prevalence and symptom burden on quality of life in patients with heart failure. Eur J Cardiovasc Nurs. 2005;4:198-206.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 285]  [Cited by in F6Publishing: 306]  [Article Influence: 16.1]  [Reference Citation Analysis (0)]
33.  Goodlin SJ. Palliative care in congestive heart failure. J Am Coll Cardiol. 2009;54:386-396.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 274]  [Cited by in F6Publishing: 285]  [Article Influence: 19.0]  [Reference Citation Analysis (0)]
34.  Rustøen T, Stubhaug A, Eidsmo I, Westheim A, Paul SM, Miaskowski C. Pain and quality of life in hospitalized patients with heart failure. J Pain Symptom Manage. 2008;36:497-504.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 36]  [Cited by in F6Publishing: 42]  [Article Influence: 2.6]  [Reference Citation Analysis (0)]
35.  Goodlin SJ, Wingate S, Pressler SJ, Teerlink JR, Storey CP. Investigating pain in heart failure patients: rationale and design of the Pain Assessment, Incidence & amp; Nature in Heart Failure (PAIN-HF) study. J Card Fail. 2008;14:276-282.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 27]  [Cited by in F6Publishing: 27]  [Article Influence: 1.7]  [Reference Citation Analysis (0)]