Stage I COPD is also known as mild, or early, COPD. There can be quite a lot of variation in how quickly a person's COPD worsens, but if a person
stops smoking and gets good medical treatment, it usually takes years for COPD to progress to more advanced stages.
Because of this, the life expectancy of a person with Stage I COPD is mainly affected by other factors, such as age, other chronic illnesses, and overall health status.
In general, research studies have found that using stage of COPD by itself is not a very accurate way to predict life expectancy or mortality. Instead, doctors can make better predictions when they incorporate additional information; one popular model (known as BODE) assigns points based on FEV1, body-mass index, distance a person can walk in 6 minutes, and how short of breath the person usually feels.
Still, one group of researchers recently did try to address this very question of life expectancy by stage of COPD. They concluded that for otherwise healthy 65-year-old men with Stage I COPD, life expectancy ranges from 14 to 18 years, depending on whether the person was a current, former, or never smoker. For otherwise healthy 65-year-old women with Stage I COPD, life expectancy ranges from 17.2 to 20.5 years. These Stage 1 life expectancies are only very slightly shorter than for "normal" people without COPD.