For those aged 5 to 44, the death rate among the most affluent households was 19% higher than the poorest.
One explanation is that wealthier people are more susceptible to a deadlier form of asthma, known as brittle asthma, which takes hold suddenly.
This form of asthma has been linked to higher rates of allergies which also tend to be more common in affluent households because of better hygiene. Normally, death rates from illnesses are highest in the most deprived households.
About 5.4 million Britons are treated for asthma, which kills an average of three people a day in the UK.
Rates of the condition increased significantly from the 1950s to the 1990s, and while they seem to have declined slightly since, figures from the Asthma UK charity show that death rates have increased by a quarter in the past five years.
For the latest study, researchers analysed 14800 deaths from asthma in England between 2005 and 2015.