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1 Congestive Heart Failure Congestive Heart Failure Marwan Nussairat HA533 April 27th , 2012 Park University Dr. Ellen DorshowGordo 2 Congestive Heart Failure Abstract Epidemiology is used widely to help us better understand diseases, how they work, and how they are transmitted. This helps us to better treat the disease. The process of epidemiology is lengthy but must be followed accurately to ensure correct diagnosis and treatment. Epidemiology is used when a new disease is found and when an old one reappears in high numbers. A common disease in the elderly is congestive heart failure (CHF). The epidemiology process can be used to better understand the disease, what causes it, and how to treat it. Now days, drugs manufactures are competing to develop new drugs to treat this condition , because many researches and studies shows that there is profound impact that congestive heart failure has on life expectancy and quality of life. Despite favorable effects on (aspects of) quality of life in short term studies, several of these new agents have been shown to reduce survival in mortality trials. However, patients with severe congestive heart failure may experience such incapacitating symptoms that the question should be raised as to whether an improvement in quality of life makes the increased risk of mortality associated with these new agents acceptable. Unfortunately, most clinical trials in which both mortality and quality of life are evaluated fail to provide information on this composite probability. 3 Congestive Heart Failure Epidemiology According to the World Health Organization (WHO), “Epidemiology is the study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems. Various methods can be used to carry out epidemiological investigations: surveillance and descriptive studies can be used to study distribution; analytical studies are used to study determinants” (WHO, 2011). To put this definition into simpler terms epidemiology is the study of disease in humans or animals and focuses on when and where they happen. Epidemiology tries to determine what causes disease and what people can do to prevent disease. Epidemiology was first used when scientists tried to discover causes of diseases such as smallpox and polio (Cornell University, 1993). Epidemiology is no longer limited to transmissible diseases. Interestingly, epidemiology can never prove a cause of a specific disease. It can only show that a certain risk factor correlates with a higher rate of a specific disease. For example, epidemiology could not prove that smoking causes lung cancer; only that people who smoke cigarettes have a higher rate of lung cancer. Epidemiology shows correlation (Cornell University, 1993). Epidemiology involves specific steps in order to determine the cause of a specific disease. Using the correct system is imperative to finding the correct answer, quickly. Step one is preparing for the fieldwork which involves researching the disease, gathering necessary equipment, and consult with all individuals involved in the investigation. Step two is to determine if an outbreak has occurred. Just because there is an increase of a specific disease does not mean an outbreak has occurred. Researching census records is part of step two. After an outbreak has been verified step three is to verify what the disease is. A specific name may not be Congestive Heart Failure 4 available however the nature of the disease should be determined. Step three involves reviewing all clinical findings including laboratory tests. Step four is defining and identifying cases. Criteria should be set that can be used to determine whether or not a person has the disease. Also, counting how many people are confirmed to have the disease. Step five is using person, place, and time to help characterize the disease. This step is vitally important in the accuracy of the investigation and the data will be collected several times throughout the investigation. This would be who has CHF, how long they have had it, and where they live. Step six is developing a hypothesis, which will help us to determine why and how the outbreak occurred. Step seven is evaluating the hypothesis to see if it accurate. There are two ways of establishing credibility: comparing the hypothesis to facts and using analytic epidemiology. An example hypothesis would be that individuals who experience high blood pressure earlier than age 35 have a high incidence of CHF. Step eight is refining the hypothesis and doing extra investigations if needed. If analytical epidemiology does not prove the hypothesis right then looking for a different way of transmission should be done. Step nine is executing prevention of the spread of the disease. Although this is listed as step nine, prevention measures should be started as soon as the disease and mode of transmission are identified. Congestive heart failure may not be 100% preventable but patients can take steps such as consuming a low-sodium diet and limiting fluid intake. Step ten is spreading the word. The official way of doing this is a conference with local health authorities along with a written report. This briefing will explain the disease, how it is transmitted, and most importantly, what can be done to prevent further spread. This educational briefing is imperative to be accurate because these health officials use this information to educate the general public. Congestive Heart Failure 5 “The transmission of communicable disease depends on the successful interaction of the infectious agent, the host, and the environment” (Stanhope & Lancaster, 2008). Infectious agents include bacteria, viruses, funguses, and parasites. The host would whatever is hosting the infectious agent such as human or animal. The environment is everything that is on the outside of the host. This includes passing the infectious host to others. There are two ways an infectious agent can be spread. The first is vertical transmission, which is the transmission from parent to child. The second is horizontal transmission, which is the transmission from one person to another. Horizontal transmission can be through sexual contact or even airborne. Infection is the entry and development of an infectious agent in the host. Disease is the outcome of an infection. Disease is when the host shows clinical signs of the infection. Communicable diseases can be spread many ways. Airborne, by bodily fluids, by touch, by sexual contact, even through animals or insects. The epidemiology triangle is comprised of the host, agent, and environment. The center of the triangle is time, which is the amount of time the agent takes to spread (Stanhope & Lancaster, 2008). Heart failure (CHF) is a cardiac disease that is caused by some kind of abnormal heart function. The result is the heart not being able to pump enough oxygenated blood to the body, or decreased cardiac output. When the ventricles fail at pumping, congestive heart failure results. Hypertension, coronary artery disease, and mitral or aortic valvular dysfunction are the most common causes of CHF (American Heart Association, 2010). Once a patient is diagnosed with CHF the next step is differentiating between which is weakened: systolic or diastolic. The long-term treatment is different between the two. Evaluating the ejection fraction will tell the patient this answer. Systolic dysfunction is defined as an Congestive Heart Failure 6 ejection fraction less than 40%. Diastolic dysfunction is the left ventricle not being able to fill properly and occurs secondarily due to loss of elasticity (Rasmussen & Renlund, 2006). Diastolic dysfunction. Treatment of CHF should be pharmacological and non-pharmacological. Patients should know the presenting signs of CHF worsening such as shortness of breath, weight gain, and inability to perform normal daily activities. Up to 65% of hospital admissions are due to the patient’s noncompliance with treatments (American Heart Association, 2010). Part of a treatment plan should be a no added salt diet, which is 2-3 grams of salt per day. Some may need daily fluid intake restricted as well. Pharmacological treatment may include diuretics, ACE inhibitors, beta-blockers, digoxin, and aspirin. Class IV is patients with symptoms (dyspnea and fatigue) while at rest. Class III is patients who are comfortable at rest but have symptoms with the littlest exertion. Class II is patients that present symptoms with normal amount of exertion and Class I are patients whose symptoms occur only as often as an individual without CHF. CHF cannot always be prevented so when patients are classified under Class I the secondary prevention measures are used. There are two types of epidemiological studies: descriptive and analytical. Collecting information that is used to encapsulate the problem does a descriptive study. Comparing groups to find the similarities that may have caused the disease does an analytical study. Studying CHF is best done using the descriptive study. Finding a common cause that contributes to the disease is most helpful in treating it. If sodium is found to aggravate CHF then it can be concluded that a low-sodium diet is useful in treating the disease. There are three levels of prevention: primary, secondary, and tertiary. All are used when it comes to treating CHF. Primary prevention is what everyone strives for. This means Congestive Heart Failure 7 preventing the disease before it happens (Center for Disease Control, 2011). Getting regular physicals and eating a heart healthy diet are primary prevention in CHF. Secondary prevention is find and treat the disease early. An example would be checking blood pressure and weight frequently. If the weight increase has already happened we have not prevented it, but found it early so that it is easily treated. Tertiary prevention is preventing further damage from a disease someone already has (Center for Disease Control, 2011). The goal is to lessen pain and complications from the disease as well as slow the disease. Taking lasix to treat CHF falls under this category. CHF Treatments (Clinical Trials) Congestive heart failure has a profound impact on quality of life and life expectancy. Dyspnoea and exercise intolerance pose major limitations to the daily activities of patients with congestive heart failure. In the management of congestive heart failure, loop diuretics and ACE inhibitors are the mainstays of therapy. Depending on the characteristics of the disease for the individual patient, a beneficial effect may also be obtained by adding digoxin and vasodilators to the treatment regimen. However, even with the most optimal treatment currently available, many patients experience incapacitating symptoms and their life expectancy is reduced significantly. Furthermore, epidemiological studies indicate a marked increase with age in both the incidence and the prevalence of congestive heart failure. The expanding knowledge of the pathophysiology of congestive heart failure has failed to provide substantial progress to the usual pharmacotherapeutic treatment of this condition, and prognosis of patients with congestive heart failure has remained poor, both in terms of life expectancy and quality of life. Over the years, several promising new drugs developed for the 8 Congestive Heart Failure treatment of congestive heart failure have been shown to decrease survival in double blinded randomized clinical trials (table I). Trial Total number patients the trial Drug (dosage) of in Xamoterol 516 Xamoterol (200mg twice daily) Enoximone 151 Enoximone (50-100mg 3 times daily PRIME-II 1906 Ibopamine (100mg 3 times daily PROMISE 1088 Milrinone (40 mg/day) VEST 3833 Vesnarinone (30 or 60 mg/day) PROFILE[ 2304 Flosequinan (75-100 mg/day) FIRST 471 Epoprostenol (median 4ng/kg/min) Table I. Double-blind, randomized clinical trials on drugs associated with a statistically significantly increased risk of mortality in patients with congestive heart failure. Regardless of the pharmacological differences among agents such as xamoterol, milrinone, flosequinan and ibopamine, their ultimate effect on survival in patients with congestive heart failure can only be considered as unfavourable. Despite the inability of these drugs to exert favourable or even neutral effects on survival in patients with congestive heart failure, many of them may improve exercise tolerance and relieve symptoms. This raises the key question as to whether we are willing to accept improved quality of life at the expense of Congestive Heart Failure 9 decreased survival, assuming that both the beneficial effect on quality of life and the unfavourable effect on survival of the drug involved have unequivocally been demonstrated. Improvement in quality of life and prolongation of life expectancy (quantity of life) are the main objectives in the treatment of patients with congestive heart failure. Some of the newer treatments of congestive heart failure have been shown to improve quality of life at the expense of increased mortality. When treating an individual patient with congestive heart failure, physicians should decide on the primary aim of the treatment for that specific patient. This actually implies a translation of state of- the-art knowledge on safety and quality of life issues into a therapeutic approach in which all the relevant patient characteristics are also taken into account. Of course, the patient must play an important role in this decision process. Obviously, an increased risk of mortality in a clinical trial does not necessarily mean that an individual patient with congestive heart failure will die earlier. Likewise, an average improvement of quality of life in a clinical trial does not necessarily mean that every individual patient will experience relief of symptoms. Use of drugs which have been demonstrated to decrease survival in patients with congestive heart failure can only be accepted, however, when the probability of improvement of quality of life and prolongation of life expectancy for those using the drug exceeds the probability of improvement of quality of life and prolongation of life expectancy for those not using the drug. In table II, the intention- to-treat analysis of exercise capacity data from the imobendan in Congestive Heart Failure (PICO) trial demonstrates that, despite a trend towards higher mortality in patients started on pimobendan, this probability is larger for those using the drug (63%) as compared to those not using the drug (59%). 10 Congestive Heart Failure Unfortunately, only few clinical trials in which both survival and (aspects of) quality of life were evaluated offer the possibility for such a comparison. Parameter Exercise capacity improved No. of pimobendan patients (%) maintained or 64 (59) 132 (63) 34 (31) 48 (23) 4 (4) 5 (2) 6 (6) 24 (12) 108 (100) 209 (100) Exercise capacity deteriorated Too sick to exercise Dead Total Table II. Intention-to-treat analysis of exercise capacity after 24 weeks of treatment with pimobendan 2.5 to 5mg or placebo. Data adapted from the Pimobendan in Congestive Heart Failure (PICO) trial 11 Congestive Heart Failure Conclusion Epidemiology can seem like a difficult process but when broken down into steps, can be used by many. Nurses can use the process to find causes Using epidemiology to help treat CHF is helpful to patients and caregivers of symptoms in their patients.. Finding the root cause is imperative in treating any disease. Preventing the disease is our first preference but in many cases heart failure cannot be prevented. Treating it is the second best way to stop the disease from worsening. Improvement of life expectancy and quality of life are both mainstays of congestive heart failure treatment. drugs which improve quality of life at the expense of an increased risk of mortality can be of value in the treatment of patients with severe congestive heart failure, provided that the probability of improvement of quality of life and prolongation of life expectancy for those using the drug exceeds the probability of improvement of quality of life and prolongation of life expectancy for those not using the drug. Appropriate treatment in these patients may imply that relief of symptoms becomes the primary aim instead of prolongation of life expectancy. Based on this risk benefit profile, clinicians will be able, in dialogue with their patients, to choose the most appropriate treatment available. 12 Congestive Heart Failure References American Heart Association. (2010). Heart failure. Retrieved from http://www.heart.org/HEARTORG/Conditions/HeartFailure Center for Disease Control CDC. (2004). Steps of an Outbreak Investigation. Retrieved from http://www.cdc.gov/excite/classroom/outbreak/steps.htm. Center for Disease Control and Prevention. Retrieved April 25th , 2012. http://www.cdc.gov/excite/skincancer/mod13.htm. Cornell University. (1993). Epidemiology. Retrieved from http://pmep.cce.cornell.edu/profiles/extonet/TIB/epidemiology.html. Fletcher, L., & Thomas, D. (2001). Clinical practice. Congestive heart failure: understanding the pathophysiology and management. Journal of the American Academy of Nurse Practitioners, 13(6), 249-257. Retrieved from CINAHL Plus with Full Text database. Rasmusson, K., Hall, J., & Renlund, D. (2006). Heart failure epidemic: boiling to the surface. Nurse Practitioner, 31(11), 12. Retrieved from CINAHL Plus with Full Text database. Stanhope, M., & Lancaster, J. (2008). Public health nursing: Population-centered health care in the community (7th ed.). St. Louis: Mosby Elsevier. World Health Organization. (2011). Health Topics: Epidemiology. Retrieved from http://www.who.int/topics/epidemiology/en. Feenstra, J. J., Lubsen, J. J., Grobbee, D. E., & Ch Stricker, B. H. (1999). Heart Failure Treatments: Issues of Safety Versus Issues of Quality of Life. Drug Safety, 20(1), 1-7.