Patterns of multimorbidity in elderly veterans

Older adults often have multiple concurrent diseases, and the number and cumulative burden of individual conditions often increases with advancing age. Nevertheless, much remains unknown about patterns of multimorbidity in older adults. The lack of attention to this topic has created substantial difficulties for clinical practice guidelines, because the standard recommendations for a single disease may not be applicable to individuals whose other conditions interact with that disease, both at the level of pathophysiology and with the medications used to treat an individual’s ailments.1–5 Identifying the most common disease clusters in older adults may help the next generation of clinical practice guidelines explicitly account for common co-occurring conditions so that they can help clinicians avoid drug–drug and drug–disease interactions. Previous work has shed important light on this question by quantifying the number of co-occurring diseases within populations, examining linkages between common conditions, and determining the healthcare outcomes and costs associated with different patterns of multimorbidity,6–20 but the existing literature has certain limitations. Most of studies in this area have evaluated a limited number of conditions or limited populations, ranked conditions based on costs and outcomes rather than prevalence, focused on two-way disease combinations (and not more-complex patterns of disease co-occurrence), and provide little information on how patterns of multimorbidity may vary between the young-old (e.g., 65–74) and the “old-old” (e.g., ≥85).8,10–12,16–21 Thus, important knowledge gaps remain, particularly in identifying the specific patterns of multimorbidity that are most common in older adults and how these patterns differ between young-old and old-old people. This study was designed to identify common patterns of multimorbidity in a nationwide sample of community-dwelling older adults receiving care in the Department of Veterans Affairs (VA) healthcare system. First, this study aimed to identify the prevalence of common diseases in older male and female veterans and how the prevalence of these conditions varies according to age and sex. Second, the study sought to determine the most common combinations of diseases in older veterans and the extent to which the prevalence of these disease clusters varies between young-old and old-old individuals. In doing so, this study focused on diseases and conditions typically identifiable using large data sources and not on geriatric syndromes, which are critically important to the health of older adults but are more difficult to ascertain using administrative data.