Multi morbidity in UK general practice- exploring its links with deprivation and life expectancy

Problem

More people are living longer and the prevalence of multi morbidity (MM) increases rapidly with age. The link with deprivation is more complex with earlier disease onset and frequent co-occurrence of mental health illness with physical conditions. Smoking may also be an important explanatory factor. The contribution of MM to inequalities in life expectancy (shortened life) and disease burden (living longer with more diseases) in relation to deprivation has yet to be quantified. Older populations and pockets of deprived communities are nearly universal in UK general practice and so an increased prevalence of multi morbidity impact substantially on GP workload.

Approach

We used electronic health records from a representative sample of 225 GP practices in England (CPRD), linked to hospital admissions and deaths, to track the incidence and prevalence of 30 chronic health conditions in a cohort of 1.1 million English people aged 45 and older and they were followed up from 2001–2010. The aim was to examine socioeconomic inequalities in the age of onset of chronic disease and pattern of disease accumulation across broad clinical groups, and quantify life expectancy with and without complex multimorbidity. Multimorbidity was defined as having two or more of 30 major chronic diseases. Multi-state models were used to estimate years spent healthy and with multimorbidity, stratified by sex, smoking status and quintiles of small area deprivation

Findings

Unequal rates of multimorbidity on subsequent survival contributed to higher life expectancy at age 65 for the least (Quintile 1- (Q1) compared to most deprived (Q5): there was a two-year gap in healthy life expectancy for men (Q1: 7.7 years [95% CI: 6.4–8.5] vs Q5: 5.4 [4.4–6.0]) and a three-year gap for women (Q1: 8.6 [7.5– 9.4] vs Q5: 5.9 [4.8–6.4]); a one-year gap in life expectancy with multimorbidity for men (Q1: 10.4 [9.9–11.2] vs Q5: 9.1 [8.7–9.6]) but none for women (Q1: 11.6 [11.1–12.4] vs Q5: 11.5 [11.1–12.2]). Inequalities were attenuated but not fully attributable to socioeconomic differences in smoking prevalence: multimorbidity onset was latest for never smokers, and subsequent survival was longer for never and ex smokers.

Consequences

Deprived groups have an earlier onset of the first disease, a quicker progression to multi morbidity, more years living with diseases and for men dying younger. The association between social disadvantage and multi morbidity is complex. By quantifying sociodemographic and smoking-related contributions to multimorbidity onset and subsequent survival, we provide evidence for more equitable allocation of prevention and health care resources to meet local needs.