Comorbid Chronic Diseases and Health-related Quality of Life in the Obese Population: a Longitudinal Analysis of a Nationally Representative Household Survey in Australia

Abstract

ObjectiveThis study aims to examine the relationship between nine comorbid chronic conditions and HRQoL separately, along with the number of chronic diseases among the Australian obese population.MethodsData for this study were sourced from three waves (waves 9, 13 and 17) of the Household, Income and Labour Dynamics in Australia (HILDA) survey. The paper studies 9,444 person-year observations from 5,524 individuals over the years 2009, 2013, and 2017. The outcome variable of HRQoL was measured through the 36-Item Short Form Health Survey (SF-36), and the main variables of interest were nine chronic conditions and the number of chronic diseases. Generalized estimating equations (GEE) were used to test the association between comorbid chronic diseases and HRQoL. ResultsThis study found a negative relationship between the number of comorbid chronic conditions and sub-scale, summary measures, and health utility index of the SF-36. Obese adults with 1, 2, 3, and 3+ comorbid chronic diseases scored lower points on the SF-36 physical component summary (b = -2.83, b = -7.37, b = -11.15, b = -14.29, respectively), mental component summary (b = -1.46, b = -2.34, b = -3.66, and b = -6.34, respectively), and in the short-form six-dimension utility index (SF-6D) scale (b = -0.030, b = -0.063, b = -0.099, and b = -0.138, respectively) compared to obese peers without comorbid chronic diseases. The number of chronic conditions was associated with reductions in the score of all eight dimensions of the SF-36. Obese people with any of the nine studied comorbid chronic diseases (heart disease, circulatory disease, hypertension, type 1 diabetes, type 2 diabetes, asthma, bronchitis, arthritis, and cancer) were associated with lower HRQoL compared to peers without that particular comorbid chronic disease.ConclusionsComorbid chronic diseases in obese individuals are associated with lower HRQoL. Increasing the number of comorbid chronic conditions is associated with a further reduction in all dimensions and summary measures of the SF-36. The findings, therefore, call for improved holistic management of obesity and interventions to reduce obesity-related comorbidities to improve HRQoL of obese Australian.