OP110 Projections of socioeconomic inequalities in multimorbidity within England between 2019 and 2039: a microsimulation model using clinical practice research datalink data*

Background

Multimorbidity prevalence has been increasing, with earlier onset, and persistent socioeconomic inequalities. Previous projection modelling has focused on multimorbidity after age 65, despite greater numbers of individuals aged under 65 living with multimorbidity. This study aimed to project the multimorbidity burden among adults, and differences by quintile of socioeconomic deprivation between 2019–2049 in England.

Methods

We developed a microsimulation model using data from a random sample of 1 m adults (18+) from the Clinical Practice Research Datalink Aurum database registered at GP practices within England between 2004 and 2019, linked to quintiles of the 2015 English Index of Multiple Deprivation (IMD) as a measure of area-level socioeconomic deprivation. We used parametric survival analysis methods to model the time individuals spent in four health states of interest: healthy, one chronic condition, basic multimorbidity (2 or more chronic conditions), complex multimorbidity (3 or more chronic conditions affecting 3 or more body systems) by sociodemographic characteristics: sex, age, IMD quintile, birth cohort, and region. These transition times were applied to a 1% sample (N = 562,880) of the 2019 Office for National Statistics (ONS) population estimates for adults aged 30–90 in 2019, and projected for 30 years. We calculated annual projected prevalence and cumulative incident cases by IMD quintile and age-group (<65/65+), and years lived without multimorbidity at age 30 by IMD quintile. Results are the median (with 95% uncertainty intervals) from a preliminary 10 model runs, scaled up to the ONS population. Analyses were conducted using R v4.2.2.

Results

Projected crude prevalence of basic multimorbidity and complex multimorbidity increases by 60%, from 45% [45%-45%] with basic multimorbidity in 2019 to 71% [71%-73%] in 2049. Between 2019–2049, 470,000 [460,000–500,000] more incident basic multimorbidity cases, and 470,000 [460,000–480,000] more complex multimorbidity cases, are projected in the most compared to the least deprived IMD quintile. This is driven by inequalities in the working-age population: a projected 1 million [1 m-1.1 m] more incident basic multimorbidity cases, and 1.5 m [1.4 m-1.5 m] more complex multimorbidity cases, among under 65s from the most deprived IMD quintile compared to the least deprived. The median expected number of years lived without multimorbidity at age 30 was 15 years [15–16] in the least deprived IMD quintile, and 13 [12–13] in the most deprived.

Conclusion

Continuing trends in multimorbidity accumulation will likely lead to substantial increases in multimorbidity prevalence by 2049, with growing inequalities, particularly pronounced among the working-age population. Equitable policies are needed to postpone or prevent multimorbidity onset.