Abstract
In this study we applied an original method of identifying diseases with high impact on mortality in older U.S. adults over the 1998–2013 period to compile a list of acute and chronic age-related diseases. We analyzed time trends in prevalence and mortality hazard ratios for 48 selected diseases in order to identify both epidemiological changes as well as possible trade-offs in the all-cause mortality risk posed by these diseases over time. We found that the beneficial downward trends in the risk of several high-impact diseases (e.g. myocardial infarction, heart failure, cardiomyopathy, and several solid cancers) is accompanied by increases in prevalence of other conditions many of which, while receiving little attention by the Public Health community, pose significant risk to life (e.g. electrolytes and liquid disbalance, anemia, weight deficiency, septicemia, and chronic kidney disease) and have adverse synergies with co-existing conditions. Since death HRs decrease for diseases with increasing prevalence, these trends could be explained, in part, by improved ascertainment. We conclude that although individuals who reach age 65 in 2013 can expect to live longer than their counterparts from earlier birth-cohorts, this increase in longevity is accompanied by higher levels of multimorbidity and an increased role of diseases previously overshadowed by the effects of high-impact cardiovascular conditions. The expected continuation of this trend past 2013 requires increased attention to the role of interactions between co-existing diseases, their treatment (including potential adverse effects of polypharmacy and other treatment-treatment interactions) and the optimization of prevention strategies for older U.S. adults.