Impaired life annuities to take advantage of poor health is akin to taking an indexed annuity to protect against inflation.
An impaired annuity consists of filing a medical report, along with your life annuity application,which shows that you have medical problems and are in poor health.But that is not why the company may or may not give you a better monthly income.
The only reason the company will improve the quote is if your life expectancy is affected.In other words if your illness gives you a maximum 5 years to live and you are now 45,then you definitely should apply.But if you are 70 years old with the same problem,you may be lucky to get any increase at all.