Purpose: Factors that predict the health-related quality of life (HRQoL) of people with complex chronic diseases have not been investigated to date. Determining the impact of disease on daily activities is a factor that is particularly important with this group of people. This study examined the influence of a range of predictors (including the impact of chronic diseases on daily activities), on HRQoL in patients with complex chronic diseases over a 12-month period.

Method: A longitudinal cohort study was conducted with outcomes measured at baseline, 3, 6 and 12 months post-baseline. Adults attending an Australian community-based rehabilitation service were included. HRQoL was measured using the SF-36 and corresponding preference-based health utility. Predictor variables included sociodemographic factors, disease factors (e.g. impact of diseases on daily activities), intervention factors, psychosocial factors and HRQoL components that were not included as the dependent variable. Linear mixed-effects regression was used to examine the relationship between predictor variables and HRQoL.

Results: Data from 351 participants were included. The impact of chronic disease on daily activities was the most frequent significant predictor of HRQoL outcomes. Other significant predictors included the impact of chronic back pain or sciatica on daily activities, the number of comorbidities, general health functioning and psychological distress.

Conclusion: Models of health care for people with complex chronic disease may be enhanced by greater focus on patients’ daily activities during assessment and intervention delivery. The range of significant predictors highlights the importance of an interdisciplinary team for managing complex chronic disease or targeted intervention strategies.