The Impact Of Chronic Disease Combinations On Mortality Rate Advancement Periods In Older Adults

Anne GILSING, McMaster University, Canada
JENAB M. 4 , RICCI C. 4 , VAN DEN HEUVEL E. 3 , SOHEL N. 1 , GRIFFITH L. 1 , FREISLING H. 2 , RAINA P. 1

1 Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada
2 Dietary Exposure Assessment Group, International Agency for Research on Cancer, Lyon, France
3 Technical University Eindhoven, Eindhoven, the Netherlands
4 Nutritional Epidemiology Group, International Agency for Research on Cancer, Lyon, France

Purpose: The number of older people living with chronic conditions is increasing and previous studies have indicated that patients with multiple chronic conditions have higher mortality rates. Yet, little is known about how specific combinations of chronic conditions impact mortality.
Methods: A total of 22,741 participants (62% women) aged 65 years of age and older from four cohorts were followed-up for vital status for an average of 10.0 years. Information on chronic disease status and confounding variables (smoking, education) was harmonized across cohorts. Using self-reported history of five chronic conditions with high mortality rates at baseline (cancer, hypertension, stroke, myocardial infarction, and diabetes), mutually exclusive groups of disease combinations were created. Cox proportional hazards models were used to estimate the rate advancement period (RAP) and corresponding 95% confidence intervals (95%CI) for all-cause mortality associated with specific disease combinations.
Results: At baseline, 58% of participants reported having two or more chronic conditions. Compared with individuals without any of the five conditions, the rate of death was advanced by 2.09, 5.56, 10.02, and 11.13 years for participants with 1, 2, 3, or ≥4 conditions, respectively. This means that individuals with four or more chronic conditions who have a certain rate of dying would be expected to have had the same mortality rate at a later age (+11.13 years) had they been disease-free. Among combinations with the same number of conditions there was substantial variability in RAPs.
Conclusion: In people aged 65 years and older, the period by which the rate of dying is advanced increases with each additional chronic condition, but discordant effects were observed across disease combinations with the same number of conditions.
Funding source: On behalf of the CHANCES project consortium; CHANCES received funding by the FP7 framework programme of DG-RESEARCH in the European Commission (grant agreement no. HEALTH-F3-2010-242244).