III. No Evidence that it is Effective, or Mixed Evidence

There are some health care interventions that are frequently ordered for patients despite a lack of evidence that it works. There may be not evidence, or their may be mixed evidence (one study may show some effectiveness, and another may find none). Here we can get substantial variation in practice patterns. An example of this is chronically ill patients spending days in the Intensive Care Unit (ICU). The ICU is generally an intensive treatment for a patient that needs substantial support temporarily. A chronically ill patient will remain ill, but can have their symptoms managed, and that outcome is unlikely to be changed by putting them in the ICU. This is a "gray area" of medicine. There are not clear and widely accepted guidelines to be followed. In such areas of medicine, judgement (and therefore practice patterns) can vary widely across physicians, hospitals, and geographic regions. As you saw when we were examining variations in care, the number of days spent in ICU among chronically ill patients varies widely across hospital referral regions.

In one or two paragraphs, explain why there are wide variations in health care expenditure on treatments and services that fit in Chandra's category III health care?