Modeling differential rates of aging using routine laboratory data; Implications for morbidity and health care expenditure

Aging is a multidimensional process where phenotypes change at varying rates. Longitudinal studies of aging typically involve following a cohort of individuals over the course of several years. This design is hindered by cost, attrition, and subsequently small sample size. Alternative methodologies are therefore warranted. In this study, we used a variational autoencoder to estimate rates of aging from cross-sectional data from routine laboratory tests of 1.4 million individuals collected from 2016 to 2019. By incorporating metrics that would ensure model's stability and distinctness of the dimensions, we uncovered four aging dimensions that represent the following bodily functions: 1) kidney, 2) thyroid, 3) white blood cells, and 4) liver and heart. We then examined the relationship between rates of aging on morbidity and health care expenditure. In general, faster agers along these dimensions are more likely to develop chronic diseases that are related to these bodily functions. They also had higher health care expenditures compared to the slower agers. K-means clustering of individuals based on rate of aging revealed that clusters with higher odds of developing morbidity had the highest cost across all types of health care services. Results suggest that cross-sectional laboratory data can be leveraged as an alternative methodology to understand age along the different dimensions. Moreover, rates of aging are differentially related to future costs, which can aid in the development of interventions to delay disease progression.