A Fresh Look at Co-morbidity

You may think you understand a disease. But then it arrives in tandem. A new survey takes a fresh look at co-morbidity.
Jan 01, 2006

As americans age, they are likely to suffer from more than one chronic condition at a time. So as the country's population grays, the rate at which patients presenting co-morbid indications will increase, as will the absolute number of patients whose treatment must be adjusted for more than one disease. These are not surprising facts, but they deserve careful consideration by pharma manufacturers and marketers.

The National Health and Wellness Survey (NHWS), a look at patient attitudes, behaviors, characteristics and demographics in about 80 markets in the United States and Europe, puts numbers to co-morbidity. By age 45, patients who suffer from one condition on a list of 20 chronic but serious diseases ranging from angina pectoris to thyroid condition are, on average, likely to have another condition from the list as well. By age 65, the average number of co-morbid conditions reaches two and a half. A better understanding of how such patients present can ultimately help produce better health outcomes for millions of Americans.

The survey also uncovers new facts about co-morbidities that are well known to be related—even if the nature of symptom overlaps are vaguely understood, or sometimes even go unrecognized—by non-specialists. Among the 214 million adults in the United States, for example, more than four in 10 have high cholesterol, hypertension, or type-II diabetes. The NHWS shows how many in this vast group of patients suffer from more than one of each of these conditions. As it turns out (see diagram, right), type-II diabetes better indicates the presence of high cholesterol and high blood pressure than the other way around.

The data also reveal new connections between symptoms and diseases, for example, pain and depression. Intuitively, pain and depression go together like mortar and pestle. That the two conditions often feed on one another has been observed for centuries. As the September 2004 Harvard Mental Health Letter put it: "Pain is depressing, and depression causes and intensifies pain."

The data bear this out. Nearly a third (31 percent) of American adults who experience pain two to three times a week have been diagnosed with depression, according to the NHWS, compared with about 18 percent of the general population. On the flip side, more than half (56.4 percent) of the people diagnosed with depression report that they experienced pain the past 12 months, compared with 37 percent in the total US population. Manufacturers of anti-depressants know this. But does the industry really know enough know about recognizing and treating depression that is co-morbid with pain-inducing diseases, such as arthritis and migraine? And how often do clinicians recognize depression among people suffering from a physically painful condition? How do physicians treat co-existing depression and what effect does it have on the experience of pain?

The topic certainly deserves further research. In fact, just over a year ago, in late 2004, the National Institutes of Health (NIH) called for more studies on the frequency and distribution of co-morbid mental and physical disorders. NIH stressed the importance of understanding the basic attitudinal and behavioral processes that could aid in the prevention and treatment of mental disorders that occur simultaneously with physical disorders.

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