Prognosis of COPD

Chronic obstructive disease worsens over time. After COPD becomes clinically apparent, the median survival is about 10 years. Prognostic variables in COPD patients are not well described. A number & factors play a role in the severity of COPD symptoms include low FEV1, active smoking status, hypoxemia, poor nutrition, the presence of cor pulmonate, resting tachycardia, low exercise capacity, severe dyspnea, poor health-related quality of life, anemia, frequent exacerbations, co-morbid illness, and low carbon monoxide diffusing capacity. People who have less severe symptoms, are a healthy weight, and do not smoke tend to live longer. Death is often due to susceptibility to intercurrent illness and other smoking-related illness such as lung cancer, cardiovascular diseases rather than progressive respiratory failure. Patients with an FEV1 less than 35 percent predicted to have about 10 percent mortality per year. If a patient reports that they are unable to walk 100 meters without stopping because of breathlessness, the 5 year survival is only 30 percent. Celli 2004 developed the BODE index score (consisting of BMI, exercise capacity, and estimates of dyspnea) which has been shown to predict survival over 1-3 years.

Table-1 Shows: BODE Index Variables & Scoring Points

Table-2 Shows: BODE Index Scores & Mortality

Ambulatory COPD patients:- the forced expiratory volume in one second (FEV1) has traditionally been used to access COPD severity. A FEV1 of less then 35% of the predicted value represents severe disease 25% of these patients will die within two years and 55% by four years. A number of other studies have shown that age, low body mass index (BMI), and low PaO2 were independent predictors that correlated to reduced survival time.

Hospitalized COPD Patients:- Mortality statistics vary for patients admitted with COPD exacerbations depending on age, functional status, co-morbidities, and physiological variables such as hypoxia and hypercarbia. Roughly 10% of patients admitted with a paCO2>50 mmHg will die during the index hospitalization, 33% will die within six months, and 43% die within one year (Connors 1996). Patients with less severe COPD have lower in hospital mortality of 25%. Poor prognostic factors include: co-morbid illness, severity of illness, low serum albumin, and/or low hemoglobin. Previous mechanical ventilation, failed extubation, or intubation for greater than 72 hours all increase mortality. In one study, patients ventilated more than 48 hours had a 50% one year survival; functional status and severity of illness were associated with short term mortality while age and co-morbidities were associated with one year mortality.