Complications:

COPD affects an estimated 340 million people worldwide. It is the fourth most common cause of death in the United States, but experts predict that it will be the third leading cause of death in the world by 2020 as the population ages and people continue to smoke.

Although COPD has traditionally been considered a man's disease, an increase in women who smoke has caused COPD to skyrocket in women. Women with COPD tend to fare worse than men -- they are more likely to be hospitalized and to die from COPD. They also report more severe symptoms, greater depression, and a worse quality of life than men.

Women appear to be more susceptible to the effects of smoking and pollution, possibly because of hormones or other genetic differences. The good news is that women who stop smoking get their lung function back more quickly than men.

The leading cause of death from COPD is respiratory failure. However, patients with mild-to-moderate COPD also tend to develop cardiovascular disease or lung cancer. This likely occurs from inflammation, which is involved in all three COPD diseases.

Traditionally, physicians have measured the severity of COPD by the amount of air that a person can forcibly exhale in one second (FEV1). The amount decreases as COPD gets worse. However, COPD affects other systems and body parts, which provide clues about the severity of the disease. Many physicians now use the BODE index to categorize COPD and predict its outcome. BODE stands for body-mass index, degree of airflow obstruction, dyspnea (breathlessness), and exercise capacity as measured in a 6-minute walk test.

• Outlook for Patients with Emphysema. If emphysema is detected before it causes symptoms, there may be some chance of reversing it. However, permanent changes in the alveoli usually occur, even in young smokers. Patients with the inherited form of early-onset emphysema are at risk for early death, unless the disease is treated and its progression stopped or slowed. Emphysema patients who have significant, unplanned weight loss (a sign of muscle wasting) have a poorer outlook, regardless of their lung function.
• Outlook for Patients with Chronic Bronchitis. Chronic bronchitis does not cause as much lung damage as emphysema, although the airways become blocked by mucus plugs, and narrow due to inflammation. Poor air exchange leads to low oxygen levels and high carbon dioxide levels. This poor gas exchange can lead to serious, life-threatening conditions that include severe breathing difficulty and heart failure.

Acute Exacerbations

Acute exacerbations are episodes that occur when the airways suddenly become blocked and symptoms get worse. These events are associated with inflammation in the airways and are generally triggered by an infection in the airway or throughout the body.

Other factors that can trigger serious lung events include:

• Certain medications
• Exposure to irritants in the air (air pollution)
• Seasonal changes (hot weather)

Acute exacerbations include the following symptoms:

• Increased phlegm
• Thicker and darker phlegm
• Shortness of breath (this is the most common and distressing acute symptom)

Acute exacerbations occur, on average, between two and three times a year in patients with moderate-to-severe COPD. In about 80% of the cases, they are triggered by infections. Smokers have more episodes than nonsmokers. Researchers have discovered that a clot that blocks an artery in the lung (a pulmonary embolus) is present in as many as a quarter of all COPD exacerbations. COPD patients are at higher risk for embolisms than the general public.

Exacerbations tend to occur in clusters. Having one exacerbation is likely to trigger another, especially within the first 8 weeks after it occurs.

Acute exacerbations get better on their own, but they are still the most common cause of hospitalization in these patients. Exacerbations often must be treated with different medications. Frequent acute exacerbations of COPD cause lung function to deteriorate quickly. Patients never recover to the condition they were in before the last exacerbation. In COPD patients who are hospitalized, mortality rates are 11%. Survivors of a first hospitalization have a 50% chance of returning to the hospital within 6 months.

Reduced Quality of Life and Mood

Nearly half of COPD patients report some limitation in daily activities. They have trouble walking up stairs or carrying even small packages. Breathing becomes hard work. More than half of patients with COPD have difficulty sleeping (insomnia). Such impairment in quality of life can negatively affect mood.

Those with COPD are more likely to have anxiety, depression, or another psychiatric disorder than people in the general population. Women with COPD are more susceptible to psychological problems than men.

If patients with COPD become anxious or depressed, they may have a poorer outlook than people without emotional problems. Depression and anxiety are associated with an increase in the frequency and length of exacerbations, as well as the number of hospitalizations. Having anxiety can cause exacerbations to last twice as long as they would otherwise. Depression also increases the risk of death in both those with stable COPD and in those with uncontrolled disease. Having depression may prevent people with COPD from eating properly, exercising, taking their medication as prescribed, and getting the medical attention they need.

Low oxygen levels also can impair mental function and short-term memory. Psychological therapy may be particularly helpful for people with COPD.

Malnourishment

People with COPD often lack good nutrition. Patients with chronic bronchitis tend to be obese. Patients with emphysema tend to be underweight. Loss of weight and muscle mass is linked to a poor outcome in COPD. Good nutrition improves the ability to exercise, which in turn builds muscle strength and lung function. Obese patients with COPD who lose weight tend to sleep better.

Heart Disease

Over time, COPD causes low levels of oxygen (hypoxia) and high levels of carbon dioxide (hypercapnia) in the body. In order to boost oxygen delivery, the body compensates in a number of ways:

• Blood vessels in the lung narrow. This leads to high blood pressure in the lungs (pulmonary hypertension).
• More red blood cells are produced to increase the blood's ability to carry oxygen.
• The heart rate increases to pump more blood.
• The breathing rate increases.

Eventually these activities can lead to very serious and even life-threatening conditions:

• Abnormally high blood pressure in the lungs can cause a complication called cor pulmonale. The right ventricle of the heart enlarges, eventually leading to heart failure.
• Chronic bronchitis is associated with a 50% higher risk of death from coronary artery disease, independent of the risks associated with smoking.
• Patients with long-term and severe hypoxia and hypercapnia are at risk for acute respiratory failure, which can cause heart rhythm abnormalities or other life-threatening conditions.

Other Serious Medical Problems Associated with COPD

The smoking that causes COPD is associated with high risks of pneumonia, lung cancer, stroke, and heart attack. Tobacco smoke contains more than 400 substances, many of which are oxidants, metals (such as lead, cadmium, and aluminum), and cancer-causing chemicals (carcinogens). Nicotine itself may not damage tissues, but it addicts smokers to tobacco.

Lung Cancer. Patients with a 30-year history of smoking and signs of limited airflow (most patients with COPD) are at high risk for lung cancer.

Sleep Disturbance. About half of all people with severe COPD experience sleep disorders such as sleep-related hypoxia or insomnia. Nocturnal hypoxia, a lack of oxygen during sleep, occurs when breathing is shallowest during rapid-eye-movement (REM) sleep. It may be due to suppression of the cough reflex and a build-up of mucus. Nocturnal hypoxia is treated with overnight oxygen therapy. As COPD worsens, many patients have trouble falling or staying asleep. COPD patients should not use sleep medications. Nighttime oxygen or a change in COPD medications from beta-agonists to anticholinergics can sometimes help restore restful sleep.

Osteoporosis. Osteoporosis (thin and weakened bones) is a significant problem in patients with COPD. Many conditions associated with COPD, including smoking, lack of vitamin D, sedentary lifestyle, and the use of corticosteroid medications put people at risk for bone density loss and osteoporosis.

Gastroesophageal Reflux (GERD). Many patients with severe COPD have GERD, a condition in which stomach acids back up from the stomach into the esophagus. However, many COPD patients don't report experiencing GERD symptoms such as heartburn.

Aspiration Pneumonia. Problems with breathing and swallowing put people with moderate-to-severe COPD at increased risk for aspiration pneumonia. This condition occurs when saliva, other fluids, or food is breathed into the airways.