As described earlier, patients with chronic and potentially disabling conditions were identified on the basis of the ICD-9-CM diagnosis codes and utilization indicators reported in their medical claims and encounter data. This resulting list of over 320 diagnoses will be referred to as per se diagnoses, because the occurrence of any of these is expected to be associated with chronic illness or disability. More than 30 additional diagnoses were identified as indicators of chronic diseases and potential disabilities if they occurred with substantial inpatient or outpatient utilization or very high expenditures during a study year. We use both methods for defining potentially disabling chronic illness in this analysis.
In addition, researchers at Harvard University developed a method for identifying people with psychiatric disabilities (Ettner et al., 1998). People were defined as having a chronic and potentially disabling psychiatric condition if they have the following diagnoses: schizophrenia or schizoaffective disorder; manic depression/bipolar disorder; autism; recurrent major depression; major depression with anxiety disorders; or substance abuse with a secondary psychiatric disorder. We will refer to this group of conditions as "psychiatric disorders" in our analyses.
Finally, we examine a set of conditions which are expected to be most highly associated with disability among adults. They were identified by LaPlante based on an analysis of the 1983-1986 National Health Interview Survey (Laplante, 1989). In this analysis, diagnoses that were most likely to be associated with reports of limitations in daily activities or work, or the inability to work, were identified; see Appendix A-1 and Appendix A-3 for a detailed list. We will refer to these as "activity-limiting conditions."
Table 7-1 illustrates the prevalence of the potentially disabling chronic conditions examined in this study for 1994 and 1995, broken down by employer. They represent diagnoses taken from Appendix A, grouped by illness. These conditions were selected because they were among the most prevalent in the populations examined and because they represent a range of disease types. Conditions defined on the basis of both diagnosis and utilization information are noted.
|TABLE 7-1. Sample Size for Selected Potentially Disabling Chronic Disease Diagnoses, by Employer, years 1994-1995|
|Employer A||Employer B|
|Chronic Obstructive Pulmonary Disease||828||1,372|