PMC patient severity scale: derivation and validation - Patient Management Category

Health Services Research, August, 1994 by Wanda W. Young, Susan Kohler, Jeanne Kowalski

Physicians also identified a subset of PMCs that are conditions likely to complicate the management of the patient and influence patient outcomes, both morbidity and mortality. These PMCs are referred to as complication PMCs even though they include a broad range of conditions that complicate medical management and are not limited to complications that result from treatment of the patient. It should be noted that, with most administrative data (and even with medical record review in some instances), it is extremely difficult to determine when the complication occurred (i.e., after admission or concomitant with the condition that led to hospitalization) and what precipitated the complication (e.g., the patient's compromised status or the treatment provided). Nevertheless, it is possible with administrative data to identify these complicating factors and to use the designated PMCs to assess the impact of complications on patient morbidity and mortality as we have done in this study.

PATIENT MANAGEMENT PATHS

During the original development, panels of physicians not only identified PMCs within each disease area, but they also specified the hospital services required for the effective treatment of a typical patient in each PMC. Each of these physician-specified management strategies, referred to as Patient Management PATHs, consists of diagnostic and treatment services (e.g., specific x-rays, scans, laboratory studies, and operative procedures required, if any) as well as expected lengths of stay in special care units and in total. These PATHs represent effective and efficient resource use for a typical patient in each category; they do not represent a prescription for care of a particular patient. An example of the form that this takes is shown in Figure 1.

The PMCs shown in this example are PMC 0508, Burn: Smoke Inhalation with Inhalation Injury, and PMC 0509, Burn: Smoke Inhalation without Inhalation Injury. Both smoke inhalation patient types require the availability of an emergency room and are typically managed with oxygen, and with laboratory and radiology studies. Additional resources, however, are required for PMC 0508, Smoke Inhalation with Inhalation Injury, including drug therapy, respiratory therapy, possible surgical intervention, and the availability of a special care unit for 7 to 14 days. The total length of stay (LOS) expected for this inhalation injury patient is 14 to 21 days in contrast to only 0 to 1 day of acute care for the smoke inhalation patient without inhalation injury. Physicians have, in fact, designated the latter PMC as a potential ambulatory patient type.

PMCs and PATHs are both conceptually and operationally distinct. The PMCs in this example are defined based on combinations of diagnosis codes (in any sequence) recorded on patient discharge abstract data. By contrast, the services on each Patient Management PATH provided, for each patient type, the basis for the identification of hospital costs, which were then used to derive a cost-based relative value scale for PMCs, reflecting the relative intensity of expected resource requirements for each patient type. Specifically, patient-related hospital costs (derived through detailed cost finding) were identified for each component of care and then accumulated for each Patient Management Category to determine the expected cost of managing that patient type.