Disease and illness are two different phenomena that overlap to a widely varying degree1. Disease is a problem with the structure or function of an organ or organ system in the body. Illness, in contrast, refers to the behavioral, emotional and cognitive reactions or consequences of that disease (for example, the behavior of lying in bed, feeling lousy and considering oneself to be unhealthy are all very common illness consequences of having the viral disease influenza). It is of course, possible to have disease without any illness if there are no troublesome symptoms. And conversely, it is possible for people to feel ill without any physical disease, for example because of psychological upset, physical over-exertion, or extreme fatigue. However, most disease produces some physical symptoms that in turn result in some degree of illness. How much a given amount of disease results in the patient being ill and perceiving himself/herself to be in poor health varies a lot from person to person, though. And in chronic diseases, where physical symptoms are present frequently over time, the degree to which people feel in poor health and have illness with their disease is of major importance, for it will likely affect their entire life outlook and functioning.
When I was the Director of a Behavioral Medicine Clinic at Eastern Virginia Medical School, where we treated a large number individuals with IBS, we had this standard questions on our health history intake form: “How would you rate your overall health?”. The were four answer options: Poor, Fair, Good, and Excellent. I found it very intriguing to see that sometimes we would get IBS patients with severe bowel symptoms who rated their overall health on this four-point scale as “Excellent” at the very time that they were coming to us seeking help for a disease that was causing them considerable trouble and suffering. And conversely, IBS patients in our clinic with only mild bowel symptoms would sometimes rate their health as “Poor” even though they did not report any other serious medical problems. In short, it became clear to me that self-perceived health of IBS patients was commonly not very closely tied to the status of the bowel symptoms that define the disorder. Many people who work a lot with IBS or other chronic illness have noted similar discrepancy between disease severity and sense of health, but what other factors than disease determines how much illness is associated with a disease has generally been poorly understood.
Today at Digestive Disease Week 2013 in Orlando, Lackner and colleagues presented an interesting analysis of this in IBS that sheds some light on this matter. They studied 235 IBS patients who had no other gastrointestinal disease. The patients completed a whole battery of questionnaires to measure their self-rated health (using a 5-point rating scale) along with psychological symptoms, general (non-gastrointestinal) physical symptoms, quality-of-life impact of the IBS symptoms, and social functioning. The investigators found that the actual severity of IBS symptoms (measured on the validated IBS Severity Scale) and how much the IBS affected life functioning only predicted self-ratings of poor health to a very minor degree (even though it was statistically significant in this large sample). Instead, a whole group of other factors that had nothing to do with bowel symptoms were more substantially associated with poor health, including fatigue, the amount of general non-gastrointestinal body symptoms or non-GI diagnoses, negative social interactions, and feeling anxious or depressed. Because so many different variables correlated with poor self-rated health, the investigators simplified their explanatory model by picking the statistically strongest contributing factors, and found in the end that three separate variables — fatigue, somatization (that is, the amount of general non-GI symptoms) and negative social interactions — added together in predicting self-ratings of poor health, and added together to produce a sense of poor health. Together, these three variables explained a total of 35% of the variability in health self-ratings.
Assuming that the three key variables identified in this study to be associated with poor self-perceived health hold up in analysis of other patient samples, these observations have clear implications for treatment of IBS (and perhaps for other chronic disease conditions as well). They confirm that IBS bowel symptoms actually play a relatively minor role in patients’ personal sense of health, and point instead to specific other aspects of IBS functioning that should be addressed to improve this important aspect of personal well-being. It seems likely that some fine-tuning or shift in emphasis in the adjunctive psychological and educational interventions that are widely used to help IBS patients could accomplish this, because the tools for addressing each of these three variables that seem to contribute substantially to a sense of poor health already exist: Cognitive behavioral therapy is ideal for addressing and neutralizing the impact of negative social interactions; hypnosis treatment reduces somatization in IBS (and cognitive behavioral therapy does so as well to some extent); and teaching patients methods that improve sleep (something that in my opinion far too often neglected in IBS, which is a disorder notorious for impaired sleep) is already done in some places and could be done much more routinely and systematically.
What is missing now, of course — even in spite of these new insights — is to explain what accounts for the rest of the variability in how healthy or ill IBS patients feel (more than half of it is still unexplained). Further research will hopefully add those missing pieces in the future, but this is a great start and a valuable addition to the research literature.
Sa1326 “Psychosocial Predictors of Self Ratings of Health in Moderate to Severe IBS Patients: What’s Involved in Feeling Healthy Besides the Severity of GI Symptoms?” Jeffrey M. Lackner, Gregory D. Gudleski, Laurie Keefer, Darren M. Brenner, Travis J Stewart, Gary Iacobucci, Rebecca Firth, Camille Simonetti, Christopher Radziwon, Susan S. Krasner, Michael D. Sitrin, Leonard A. Katz, Sarah Quinton and Elyse Sklar. University at Buffalo, SUNY, Buffalo, NY; Northwestern University, Chicago; Wayne State University, Detroit, MI
Presented at Digestive Disease Week in San Diego, May 18, 2013.
Helman CG. Disease versus illness in general practice. J R Coll Gen Pract. 1981 September; 31(230): 548–552
Jeffrey Lackner, Ph.D., Associate Professor of Medicine at the University of Buffalo, SUNY, and Principal Author of this Study Report, in the Poster Session at Digestive Disease Week 2013 Today.