Many of our analyses focused on individuals diagnosed with one or more of a subset of nine clinical conditions in order to better understand similarities and differences between different types of episodes for different types of patients. We sought a mix of acute and chronic conditions that make up a large portion of Medicare cases (i.e., volume) and/or costs. We define and refer to "acute" episodes as those that are time-limited in duration. An acute episode, as used in this report, does not refer to episodes that involve care provided solely in an inpatient acute care hospital setting, although a time-limited event such as a hip fracture episode would involve care in the inpatient hospital setting. Rather, an acute episode is one of short duration (e.g., sinusitis, heart attack, hip fracture), which may touch one or more settings of care including an inpatient acute care hospital.
We also tried to select clinical conditions that cover the spectrum types of conditions and services received by Medicare beneficiaries. For example, we selected a mix of clinical conditions such that some are treated predominantly in a single setting (e.g. ambulatory care) while others are treated in multiple settings including inpatient and post-acute care. To build on the work previously performed by MedPAC, we included some of the clinical conditions that were the focus of their analyses.31 The following conditions are included in our analyses.
- Acute myocardial infarction
- Bacterial pneumonia
- Breast cancer
- Cerebrovascular disease
- Chronic obstructive pulmonary disease
- Congestive heart failure
- Hip fracture
- Low back pain
These nine clinical conditions were identified using primary and secondary ICD-9 diagnosis codes in 2005 Medicare claims data. For conditions that are part of the CMS Chronic Care Warehouse, we used the CMS definition. For other conditions, we used published definitions from the literature. Appendix A contains the specific codes and the sources of the codes for each of the above listed conditions.
ETGs and MEGs were run by Acumen, LLC on data for the entire study population (not just those with the above-mentioned clinical conditions) to produce summary statistics. Appendix B presents the specific settings Acumen used to run the analyses for this study.
For each condition, we designated episodes as being "related" or "unrelated" to the specific condition. Appendix C lists the specific episodes within each grouper tool that we considered directly related to the conditions of focus. - Some of the "unrelated" episodes reflect comorbid conditions that commonly co-occur with the condition of focus (e.g. hypertension was considered unrelated to acute myocardial infarction).
Figure 1: Overview of Analyses
Figure 1 provides a high-level illustration of the approach used in our analyses. The study population for this work consisted of Medicare FFS beneficiaries who were continuously enrolled in FFS Medicare Part A and Part B for 2004-2006, whose reason for eligibility was their age, and whose primary residence in 2005 was in one of three states: Florida, Oregon, or Texas. As a result of our inclusion criteria, we excluded beneficiaries enrolled in a Medicare Advantage plan for any of the analyses period.