Multimorbidity: What Do We Know? What Should We Do?

Aging is characterized by rising susceptibility to development of multiple chronic diseases and, therefore, represents the major risk factor for multimorbidity. From a gerontological perspective, the progressive accumulation of multiple diseases, which significantly accelerates at older ages, is a milestone for progressive loss of resilience and age-related multisystem homeostatic dysregulation. Because it is most likely that the same mechanisms that drive aging also drive multiple age-related chronic diseases, addressing those mechanisms may reduce the development of multimorbidity. According to this vision, studying multimorbidity may help to understand the biology of aging and, at the same time, understanding the underpinnings of aging may help to develop strategies to prevent or delay the burden of multimorbidity. As a consequence, we believe that it is time to build connections and dialogue between the clinical experience of general practitioners and geriatricians and the scientists who study aging, so as to stimulate innovative research projects to improve the management and the treatment of older patients with multiple morbidities.

Older males are known to carry, more likely than younger people, one or more chronic diseases with an expected impact on mortality. This study was aimed at identifying the relationship of prevalent chronic diseases in elderly populations of different countries with all-cause mortality. Men aged 65-84 from defined areas were enrolled in Finland (N=716), the Netherlands (N=887) and Italy (N=682). They were survivors of cohorts studied for 25 years within the Seven Countries Study. Major chronic diseases were diagnosed at entry. Ten-year follow-up for mortality was completed. Entry prevalence of selected chronic diseases was higher in Finland (56%) than in Italy (51%) and the Netherlands (44%). Ten-year age-adjusted death rates from all causes were higher in Finland (565 per 1000) and lower in the Netherlands (478 per 1000) and Italy (445 per 1000). The absolute risk of death related to chronic disease was high in the three countries, but was higher in Finland than in the Netherlands and Italy. The most lethal condition was stroke, with 10-year death rates of 806 per 1000 in Finland and 707 and 729 per 1000 in the Netherlands and Italy, respectively. The relative risk of all-cause mortality for a set of seven chronic diseases (coronary heart disease, heart failure, claudicatio intermittens, cerebrovascular accidents, diabetes, COPD and cancer) adjusted by age, other diseases and cohort was less than two for each condition, except cerebrovascular accidents in the Netherlands (RR 2.20). In general, relative risk was higher in Finland, intermediate in the Netherlands and lower in Italy, where only cerebrovascular accidents, intermittent claudication, diabetes and the presence of any chronic condition had a significant relative risk. About one third of men had one chronic disease, and between 10% and 15% had two diseases. The coexistence of any two or three chronic conditions was associated with a relative risk of 2 or more in Finland and the Netherlands and less than 2 in Italy. In these elderly men prevalent morbidity and comorbidity was relatively common and it explained a large proportion of excess in all-cause mortality in 10 years of follow-up.