Patients with comorbid illnesses present the major cause of expenses in Medicine. The majority of older adults have two or more chronic conditions; among patients with diabetes, 40% have at least three. Kerr and coworkers wished to understand how the number, type, and severity of comorbid conditions influence the self-management and treatment priorities of patients with diabetes. Data gathered from a total of 1,901 diabetes patients who responded to the 2003 Health and Retirement diabetes survey were analyzed. Analyses assessed the association between presence of comorbidities and each of two self-reported outcomes, diabetes prioritization and self-management ability. Comorbidity was characterized first by a count of all comorbid conditions, then by the presence of specific comorbidity subtypes (macrovascular and microvascular), and finally by severity of one serious comorbidity: heart failure. The study found that 40% of respondents had at least one microvascular comorbidity, 79% had at least one macrovascular comorbidity, and 61% had at least one non-diabetes-related comorbidity. Patients with a greater overall number of illnesses placed lower priority on diabetes and had worse diabetes self-management ability scores. However, only macrovascular and non-diabetes-related comorbidities, but not microvascular comorbidities, were associated with lower diabetes prioritization, whereas higher numbers of microvascular, macrovascular, and non-diabetes-related conditions were all associated with lower diabetes self-management ability scores. Severe, but not mild, heart failure was associated with lower diabetes prioritization and self-management scores.

VALUE OF STUDY TO READERS: Kerr and coauthors concluded that the type and severity of comorbid conditions, and not just the comorbidity count, influence diabetes patients' self-management. Patients with severely symptomatic comorbidities and those with conditions they consider to be unrelated to diabetes may need additional support in making decisions about care priorities and self-management activities. The study points out one of the main challenges facing those who conduct self-management research in patients with diabetes and other chronic conditions: how to teach the skills so they are used not only to manage diabetes, but to control other comorbid conditions experienced by patients. As comorbid conditions are expected to rise with the increase in age, this is not a problem to be taken lightly. It is one that is going to require a considerable amount of research in the coming decades. Studies such as this merely point out the extent and complexity of the problem. Another issue here is to find out how the interactions among the many medications taken for comorbid conditions influence the progress of diseases, as well as self-management. We also have limited information on this topic.

E.A. Kerr et al. Beyond Comorbidity Counts: How Do Comorbidity Type and Severity Influence Diabetes Patients' Treatment Priorities and Self-Management? Journal of General Internal Medicine, 2007.