Long-term accrual of conditions following myocardial infarction: a study of disease trajectories in the Wales Multimorbidity e-Cohort.

backgroundImproved survivorship following myocardial infarction (MI) has resulted in transferred morbidity to other long-term conditions (LTCs). Understanding of disease accrual over time following MI has been limited by a lack of methodologies that consider real-world complexity. We characterised post-MI multimorbidity trajectories in a real-world population of individuals following MI.

methodsThis population-wide retrospective study comprised all individuals with MI in the Wales Multimorbidity e-Cohort (which included linked primary and secondary care data for 2,902,101 GP-registered residents of Wales; 2005-2019). Single-year post-MI disease clusters and multi-year latent multimorbidity trajectories were constructed from 227 chronic conditions and 62 acute conditions, using non-negative matrix factorisation (NMF). Multinomial logistic regression identified sociodemographic factors associated with single-year post-MI disease clusters. Time-updating flexible parametric survival models quantified the association between multi-year multimorbidity trajectories and long-term all-cause mortality, adjusting for age, sex, year of MI, socioeconomic deprivation and rurality.

resultsIn total, 70,529 individuals had an incident MI during the study period (median [interquartile range] age 72 [62-82] years; 40.6% female), with restricted mean post-MI survival of 8.1 years. At MI diagnosis, 67,023 (95.0%) had ≥ 2 LTCs (median 8 [interquartile range; IQR 5-12]), which increased to 99.8% at 1 year (50,633/50,737 surviving patients, median [IQR] 12 [7-17]). NMF classified individuals into one of 10 post-MI disease clusters, based on all observed acute and chronic diagnoses (n = 3,954,622) accrued over time. Individuals that followed the most adverse latent multimorbidity trajectory (n = 26,035, 36.9%) were characterised by recurrent MI, acute infections and renal disease and had an increased risk of all-cause mortality (adjusted hazard ratio 6.62; 95% CI: 6.09-7.20) compared with individuals in the least adverse trajectory.

conclusionsPatients with MI have a high pre-existing multimorbidity burden that increases post-MI. Using NMF, we were able to reduce the real-world complexity of all individual diseases accrued over time into 10 latent post-MI multimorbidity trajectories. These trajectories were characterised by specific patterns of acute and chronic conditions, with differential impact on outcomes. These trajectories may enable the implementation of targeted strategies for individuals that are at greatest risk of adverse outcomes.