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Measuring the Impact of IBD When I was a medical student, I had an old, cantankerous professor who would always interrupt my carefully constructed presentation of a patient's history by barking, "Is the patient 'sick' or 'not sick'?" I would then dive back into my memorized speech and he would again interrupt with an expletive: "Enough of these details! What do you think when you look at the patient -- 'sick' or 'not sick'?" While this may be an effective way to teach medical students how to get to the point of a case history, it leaves a lot to be desired when trying to evaluate people with IBD.
About 40 years ago, doctors started to create more objective scales to rate disease severity in IBD patients. The introduction of these scales, or indices, was largely the result of the first clinical drug trials for IBD. In 1955, Drs. Truelove and Witts conducted the first such study, a placebo-controlled trial of steroid treatment in ulcerative colitis. In the course of their research, they devised a system for categorizing disease activity into mild, moderate, and severe colitis. The so-called Truelove and Witts Index measures the following variables:
- daily bowel movements
- rectal bleeding
- temperature
- heart rate
- hemoglobin
- sedimentation rate (the speed at which red blood cells settle to the bottom of a column of blood that has been treated chemically to prevent coagulation)
We still use the Truelove and Witts Index to evaluate disease severity in ulcerative colitis patients. Refinements to this index have produced other measuring tools such as the Lichtiger Index or the Mayo Clinic Score for ulcerative colitis severity.
It is very important to remember that all of these scores are useful primarily in conducting clinical studies of these diseases. They are rarely, if ever, used in clinical practice. Today, we use many indices to make it easier for patients and doctors to determine whether a patient is "sick or not sick." Some of the newer indices allow us to broaden our definition of severity to include how IBD affects everyday quality of life. Often, the definition of "sick" or "well" gets lost in the translation. As a result, a doctor may claim a treatment to be a success, while the patient still claims to feel lousy. Such scales try to dissect the elements of a person's condition, quantify them, and reduce the chance of disagreement among doctors-and between doctor and patient.
The Crohn's Disease Activity Index (CDAI), one of the most commonly used indices, gives a score based on a diary kept for 1-7 days, among other variables (e.g., the patient's weight and hematocrit -- the proportion of the blood that consists of red blood cells). The CDAI is only used for clinical trials and has several problems. Critics of the CDAI point out the fact that severe irritable bowel syndrome can give a high score in this index, and that the score for remission was chosen arbitrarily. However, with all of its faults it remains the most commonly used of the Crohn's disease activity indices. CDAI scores greater than 150 indicate active disease with a poorer prognosis than scores of less than 150. Since the CDAI is not as accurate for monitoring disease activity in children, a second scale known as the pediatric CDAI (PCDAI) was developed. The PCDAI correlates disease severity and activity to levels of serum albumin -- a group of proteins in the blood responsible for maintaining osmotic pressure. Once again, this index is primarily used in clinical research trials.
Multiple other indices assess disease severity for both Crohn's disease and ulcerative colitis. While these combine a person's subjective experience of the disease with objective data, they may still miss the mark in terms of describing the patient's complete experience of the illness. Clinicians have even tried to individualize these indices by focusing on specific goals for the improvement of each patient. The score reflects changes in the patient's condition, based on problems unique and important to that person.
Do any of the objective scales of disease activity consider the impact of IBD on everyday life? Not quite. The scores tend to rely on the number of bowel movements, presence or absence of bleeding, and the need for antidiarrheal medicines. But other indices, which explore the impact of IBD on broader quality-of-life experience, are being used increasingly in clinical trials. These scales can demonstrate the psychological and social impairment that can accompany IBD. The experience of IBD can vary from person to person, even when symptoms are identical. A symptom tolerable to one person may be intolerable to the next. Many quality-of-life indices can reveal degrees of impact on the patient's life that a standard clinical history might miss. Feeling good about yourself, achieving job satisfaction, happiness in a relationship, and the ability to enjoy sex are a few key issues that physicians tend to skirt.
As these rating systems come into wider use for clinical trials, we can compare them from study to study, and even country to country. Ultimately, we can use these newer scales to compare drug responses among people with IBD across cultural lines. The issue of quality of life has fully permeated the thinking of physicians and clinical investigators. People with IBD are sure to benefit from this development.
JAMES F. MARION, M.D.
Assistant Clinical Professor of Medicine
Mount Sinai School of Medicine
New York, NY
Date Posted: February 2, 2006 |
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