The IFS said that the poor often have to stop work early due to illness.
For two years, researchers at the IFS and the University of London followed the lives of nearly 9,000 people in England born before 1952.
The English Longitudinal Study of Ageing (ELSA) investigated areas including health, work, spending, receipt of healthcare, social participation and cognitive ability.
The research examined how each of these areas varies according to an individual's level of wealth and income.
However, for healthcare provision, the study found the treatment given to rich or poor was much the same.
"Few differences in the quality of healthcare were reported by wealthier respondents compared with poorer respondents," said Dr Nick Steel, of the University of East Anglia and one of the report's author.
"This suggests that healthcare for the interventions studied is provided equitably to those in need, regardless of socio-economic status, for those who have seen a doctor or nurse."
The authors of the IFS study noted that "less glamorous" conditions, including urinary incontinence, recurrent falls and poor balance, seemed to be less well treated than conditions that were of "greater public health importance".
