A Fresh Look at Co-morbidity

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.

Depression is Now a Household Word

Based on the 2005 NHWS, nearly one in every five American adults (18 percent, or about 39 million people) has been diagnosed with depression. That is low compared with the percentage of depressed people among arthritis and migraine patients.

What is a Marketer to Do?

The NHWS indicates that 28 percent of all diagnosed arthritics (and 34 percent of those diagnosed with rheumatoid arthritis) are also diagnosed with depression, as are 40 percent of migraine patients. It is interesting that the connection with depression is strong for both diseases, even though they are so dissimilar. Arthritis is a chronic condition with half the patients over 55 years of age, while migraine is an acute (albeit recurring) condition afflicting many younger people—half of migraine suffers are under 44. The common denominator is, of course, pain.

The number of patients afflicted with both high cholesterol and depression, at 23 percent, is much closer to the percentage of the population that suffers from depression (18 percent). People with high cholesterol experience no pain as a result of their condition, and not coincidentally, they don't experience depression with a much greater frequency than the overall US population.

An Age of Depression

Seniors are the patients least likely to be dianosed with depression. Just over 16 percent of the US population is over 65, but seniors represent only eight percent of the diagnosed depressed population. Similarly, one in three arthritics is over age 65, but seniors represent just 15.6 percent of arthritics who have been diagnosed with depression. And the distribution of diagnosed depression among patients with migraines tracks the distribution of depression in the general population—except for seniors. The incidence of migraine among seniors is small, but the incidence of concomitant depression is smaller than what would be expected.

There is no logical reason why depression should occur less frequently among the aged (and many reasons why it might occur more frequently). So undiagnosed cases are a better explanation of these statistical disparities than a lower incidence of depression.

The National Institute of Mental Health suggests that depression often goes undiagnosed or untreated in the elderly because:

• Older people are often reluctant to discuss their feelings with physicians.

• Depressive symptoms may be dismissed as a normal part of aging.

• Some symptoms may be excused as crankiness or grumpiness.

• Attention problems related to depression may look like Alzheimer's disease.

• Mood changes may also be caused by medicines for blood pressure or heart disease.

To marketers of antidepressants, the segment of patients over age 65 represents an underserved population—many of whom may be reached when they are visiting a physician because of pain symptoms.

On Remote Control

Clinical depression carries with it feelings of extreme sadness, guilt, helplessness, and hopelessness. It is thus easy to understand why people's fundamental attitudes toward health (and their ability to control it) correlate strongly to their tendency to be depressed when they have a pain-inducing illness.

Both arthritis and migraine sufferers with co-morbid depression are significantly more likely than their counterparts without depression to agree or strongly agree with the statement, "No matter what I do, if I'm going to get sick, I will." Similarly, they are significantly less likely to agree with the claims, "I am in control of my health" and "If I take the right actions, I can stay healthy."

Of course, it is not possible to untangle the cause-and-effect relationship between such a worldview and depression; these views could either contribute to, or be a byproduct of, depression. But people with such a fatalistic view of their health may exacerbate their conditions by being slow to seek treatment and noncompliant in following doctor's orders.

Well Treated

The NHWS data revealed that patients' primary care physicians, general practitioners, and internists diagnose depression slightly more often for people with arthritis and migraines than for the depressed population in general. Such doctors diagonse depression 44 percent of the time for all depressed patients, and 49 percent of the time for arthritis and migraine patients. Psychiatrists made the depression diagnosis about a third of the time across all three categories of patients. So patient pain does not impair physicians' ability to spot co-morbid depression (other than perhaps in the elderly, as discussed previously).

In fact, based on a comparison of self-reported cases of depression and diagnosed cases of depression, patients diagnosed with either arthritis or migraines actually stand a better chance than the population in general of having a physician diagnose their depression. Among respondents self-reporting depression, 28 percent say their condition has not been diagnosed, compared to 14 percent of people with arthritis or migraines along and depression, and 17 percent with high cholesterol and depression. Reporting a painful ailment to a doctor increases the likelihood that co-morbid depression will be noticed. Painful ailments do not obscure the mood disorder, at least when all patient ages are taken together.

What is more, a depression diagnosis leads to treatment somewhat more often for people with a painful physical condition than in the general, depressed patient population. And, for people with arthritis, the depression treatment is a little more likely to be a prescription medication.

For Better or Worse

How much does treating depression mater to the treatment of arthritis or migraine? Does treating co-morbid depression in arthritis and migraine patients enable patients to function at a different level? Are their health outcomes significantly improved on both the mental and physical front? How does the type of depression treatment make a difference?

It is possible to shed light on this by comparing "SF 8" scores across patients in both diseases, broken out by the type of depression treatment they receive (none, Rx, OTC, or Rx and OTC in combination). (Short Form 8 scores are a multi-purpose, generic measure of health status developed by Quality Metric that consists of eight questions designed to assess physical functioning, role limitations due to physical health problems, bodily pain, general health, vitality, social functioning, role limitations due to emotional problems, and mental health. A score of 50 is the norm.)

NHWS data confirm the fact that the presence of depression significantly impacts the mental and physical SF 8 scores for both arthritis and migraine patients. The mental SF 8 score for arthritis patients without co-existing depression is 51, and 40 for those with undiagnosed depression. For migraine sufferers, the presence of untreated depression pulls the mental SF 8 score down from 48 to 38. In both cases, the physical score drops two points with the presence of untreated depression.

Patients whose symptoms are severe enough to be receiving a prescription medication for their depression have even lower scores. Unfortunately, we don't know how low their scores were before they began depression treatment, only that even in treatment they remain markedly more limited than their counterparts without depression. It is important to note that this particular analysis did not take into account the type of concomitant treatment that patients may or may not receive for their arthritis or migraine (although this variable could easily be factored in).

Curiously, arthritis and migraine patients treating their depression with an OTC product score the highest of any of the depressed groups in the physical SF 8 score. This suggests that their symptoms may not have been as severe to begin with.

Pain and depression may be forever inextricably linked, but with proper diagnosis and treatment, the two conditions will not launch a downward spiral of greater suffering. The same is true of other co-morbid conditions. By sharing information on the incidence, symptoms, and treatment outcomes of people suffering more than one affliction at once, the pharmaceutical industry can work with healthcare providers to improve the quality of life for millions of Americans.

Michael Fronstin is vice president of sales for Consumer Health Sciences, which produces the National Health and Wellness Survey. He can be reached at michael.fronstin@chsinternational.com