Background The existence of wide inequalities in health across England is well-documented. Our research adds to this evidence on inequalities in self-reported health by describing current patterns and projecting future patterns of inequality in diagnosed illness across multiple conditions by deprivation.

Methods We used the IMPACT_NCD microsimulation model that simulates a close-to-reality synthetic population of adults in England from 2019 to 2040. This model uses administrative patient-level healthcare data that combines primary and secondary care records (Clinical Practice Research Datalink Aurum and Hospital Episode Statistics), mortality data (Office for National Statistics), survey data on key health risk factors (Health Survey for England) with epidemiological evidence on the relationship between chronic illness and risk factors (systematic reviews and meta analyses) and population projections (Office for National Statistics).

We used the Cambridge Multimorbidity Score (CMS) as our multimorbidity measure. This assigns a weight to 20 common long-term conditions based on individuals’ healthcare use and their likelihood of death. We further focus on ‘major illness’. This corresponds to a CMS greater than 1.5. This is an indicator of illness that involves high healthcare needs or substantial risk of mortality. We then use this measure of major illness to calculate an alternate healthy life expectancy measure: major illness-free life expectancy (MIFLE) i.e. the average number of years lived without major illness.

Analyses were conducted using R v4.0.2.

Results In preliminary results, we project that health inequalities are not projected to improve between 2019 and 2040. In 2019, the difference in major illness-free life expectancy between the most and least deprived 10% of areas in England was 10.4 years. This is projected to remain largely unchanged at 10.7 years (8.8, 11.7).

We also find that in 2019, the share of working age people living with major illness in the most deprived 10% of areas in England (14.6%) was more than double the rate seen in the least deprived 10% of areas (6.3%). In 2040, we project these rates to remain largely unchanged at 15.2% (13.0%, 17.6%) and 6.8% (5.4%, 9.1%) respectively.

Discussion Health inequalities are projected to persist into the future. This has significant implications not just for population health but for labour supply and wider economic growth. Action focussed on risk factors linked to illness is necessary but insufficient to tackle health inequalities; it requires bolder long-term effort across government and the economy to address the underlying causes of health inequality.