Sociodemographic Characteristics and Longitudinal Progression of Multimorbidity: A Multistate Modelling Analysis of a Large Primary Care Records Dataset in England
Authors: Chen Sida , Marshall Tom , Jackson Christopher , Cooper Jennifer , Crowe Francesca , Nirantharakumar Krish , Saunders Catherine L , Kirk Paul , Richardson Sylvia , Edwards Duncan , Griffin Simon , Yau Christopher , Barrett Jessica K 
Published: March 2023

AbstractBackgroundMultimorbidity, characterized by the coexistence of multiple chronic conditions in an individual, is a rising public health concern. While much of the existing research has focused on cross-sectional patterns of multimorbidity, there remains a need to better understand the longitudinal accumulation of diseases. This includes examining the associations between important sociodemographic characteristics and the rate of progression of chronic conditions.Methods and findingsWe utilized electronic primary care records from 13 million participants in England, drawn from the Clinical Practice Research Datalink (CPRD Aurum), spanning from 2005 to 2020 with a median follow-up of 4.71 years (IQR: 1.78, 11.28). The study focused on five important chronic conditions: cardiovascular disease, type-2 diabetes, chronic kidney disease, heart failure and mental health conditions. Key sociodemographic characteristics considered include ethnicity, social and material deprivation, gender, and age. We employed a flexible spline-based parametric multistate model to investigate the associations between these sociodemographic characteristics and the rate of different disease transitions throughout multimorbidity development. Our findings reveal distinct association patterns across different disease transition types.Deprivation, gender and age generally demonstrated stronger associations with disease diagnosis compared to ethnic group differences. Notably, the impact of these factors tended to attenuate with an increase in the number of pre-existing conditions, especially for deprivation, gender and age. Furthermore, the impact of deprivation, gender, and age was typically more pronounced when transitioning from a mental health condition. A primary limitation of our study is that potential diagnostic inaccuracies in primary care records, such as underdiagnosis, overdiagnosis, or ascertainment bias of chronic conditions, could influence our results.ConclusionOur results indicate that early phases of multimorbidity development could warrant increased attention. The potential importance of earlier detection and intervention of chronic conditions is underscored, particularly for mental health conditions and higher-risk populations. These insights may have important implications for the management of multimorbidity.Author summaryWhy Was This Study Done?Multimorbidity, the presence of two or more chronic conditions in an individual, is a growing concern in aging societies. A better understanding of how these conditions develop and progress over time, and the factors associated with this process, is important for more effective management and treatment.Previous research has analysed the association between certain socioeconomic and behavioural factors and the rate of disease progression over time. However, these studies typically focused on a limited number of conditions and rarely considered all possible combinations. Furthermore, their analyses often rely on relatively small datasets.There is a gap in our detailed understanding of the impact of sociodemographic characteristics – such as ethnicity, deprivation, age, and gender - on the progression of multiple chronic conditions.What Did the Researchers Do and Find?We analysed the health records of over 13 million participants in England from 2005 to 2020, focusing on how factors like ethnicity, deprivation, gender and age are associated with the accumulation of five common conditions: cardiovascular disease (CVD), type-2 diabetes (T2D), chronic kidney disease (CKD), heart failure (HF), and mental health conditions (MH).We found that factors like deprivation, age, and gender generally have a stronger link to the diagnosis of these conditions compared to ethnicity. Moreover, the impact of deprivation, age and gender tend to be weakened as the number of pre-existing conditions a person has increases.In particular, when an individual already has a mental health condition, and if they were older, male, or from more deprived groups, they were expected to develop other conditions like CVD, T2D and HF more quickly compared to scenarios involving other pre-existing conditions.What Do These Findings Mean?ur findings suggest that early stages, when people are starting to develop multiple health issues, especially when mental health problems are first diagnosed and in high-risk groups, may require more attention for improved patient care and healthcare strategies.ur results underscore the need to investigate and better understand the different biological, psychological, and societal factors that influence the progression to multimorbidity.that our analysis is based on health records, which may have incomplete or inaccurate information, including potential inaccuracies in condition diagnosis. These limitations may have an influence on our results.