Multiple Morbidity and Comorbidity

Multiple Morbidity

Research indicates that there are patterns of multiple morbidities among people in the general population. Results from the National Health Interview Survey indicate that the percentage of people age 60 years and older who reported having two or more of the nine most common conditions increased steadily with age. The 10 conditions are arthritis, hypertension, cataracts, heart disease, varicose veins, diabetes, cancer (except nonmelanoma skin cancer), osteoporosis, hip fracture, and stroke. Specifically, the percentage of women who reported two or more conditions increased from 45% (among those 60 to 69 years of age), to 61% (among those 70 to 79 years of age), to 70% (among those age 80 years and older). Among men, the percentages were 35%,47%, and 53%, respectively. These results provide compelling evidence that multiple morbidity is not unusual in older populations. On the contrary, for most older people, multiple morbidity provides the best characterization of general health. Moreover, as an indication of the severity of multiple morbidity, the presence of two or more health conditions is associated with an increased likelihood of functional limitations and disability. Multiple studies on non-Hispanic Whites and African Americans in the United States indicate that multiple [Page 394]morbidities are associated with race and ethnicity. African American men and women are more likely to exhibit multiple morbidities than are non-Hispanic White men and women. Therefore, it might be that studies that focus on a single health condition may underestimate the extent of health disparities between non-Hispanic Whites and African Americans in the United States.

Comorbidity

Most of the research on multiple health conditions has focused on comorbidity; that is, studies in which the participants consist of people with an index condition. Many studies on comorbidity have focused on heart disease and cancer in older populations. There are two consistent findings from the research in this area. First, older patients with comorbidity have shorter duration and poorer quality of life than do patients without comorbidity after taking into account other prognostic indicators. Second, patients with comorbidity are typically administered less intensive forms of therapy than are patients without comorbidity, again after taking into account relevant covariates. One common interpretation of this finding is that physicians are concerned that standard therapies for either heart disease or cancer may be too risky in the presence of other conditions. Researchers and practitioners in geriatrics have incorporated measures of comorbidity, together with other prognostics indicators (e.g., physical functioning, cognitive functioning), to better characterize the physiological age of patients. Results of such assessments are used to tailor specific treatments for older patients with multiple conditions.

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