Longitudinal associations of multimorbidity,disability and out-of-pocket health expenditures in households with older adults in Mexico: The study on global AGEing and adult health (SAGE)

BackgroundEmpirical evidence suggests that multimorbidity and disability are each significantly associated with out-of-pocket (OOP) health expenditures; however few efforts have been made to explore their joint association with OOP health expenditures.ObjectivesTo estimate the association of multimorbidity and disability with OOP health expenditures in households with older adults in Mexico, as well as the potential interaction effects of multimorbidity and disability on OOP health expenditures.MethodsLongitudinal study based on data collected as part of the Study on global AGEing and adult health Wave 1 (2009) and Wave 2 (2014), a nationally representative study in Mexico with a sample of older adults aged 50 and older. The dependent variable was OOP health expenditures, and main exposure variables were multimorbidity and disability. Two-Part regression models were used to analyze the relation between multimorbidity, disability and OOP health expenditures.ResultsMultimorbidity was associated with the probability of incurring OOP health expenditures (OR = 1.28, CI_95% 1.11–1.48), and also the tertiles of disability (2nd tertile: OR = 1.45, CI_95% 1.23–1.70; 3rd tertile: OR = 2.19, CI_95% 1.81–2.66). The presence of multimorbidity was associated with an increase of 13% in average OOP health costs (β = 0.13, CI_95% 0.01–0.25), and 16% for the 3rd tertile of disability (β = 0.16, CI_95% 0.01–0.31). We did not find significant interaction effects of multimorbidity and disability.ConclusionsMultimorbidity and disability appear to be important determinants of OOP health expenditures. The economic implications for the households and the health system should be highlighted, particularly in low- and middle-income countries because of the rapid growth of their aging populations.