Abstract
Context: Physicians often encounter patients with functional pain disorders such as irritable bowel syndrome (IBS), fibromyalgia (FM), and their co-occurrence. Although these diseases are diagnosed exclusively by patients' report of symptoms, there are few comparative studies about patients' perceptions of these diseases.
Objective: To compare perceptions of these conditions among 4 groups—3 clinical groups of older women with IBS, FM, or both disorders (IBS plus FM) and 1 similarly aged control group of women with no IBS or FM—using their responses to survey questions about stressful life events, general physical and mental health, and general medical, pain, and psychiatric comorbidities.
Method: Using data from the Biopsychosocial Religion and Health Study survey, responses from women were compared regarding a number of variables. To compare stress-related and physical-mental health profiles across the 4 groups, 1-way analyses of variance and χ2 tests (with Tukey-Kramer and Tukey post hoc tests, respectively) were used, with α set to .05.
Results: The present study comprised 3811 women. Participants in the control group, the IBS group, the FM group, and the IBS plus FM group numbered 3213 (84.3%), 366 (9.6%), 161 (4.2%), and 71 (1.9%), respectively, with a mean (standard deviation) age of 62.4 (13.6), 64.9 (13.7), 63.2 (10.8), and 61.1 (10.9) years, respectively. In general, participants in the control group reported fewer lifetime traumatic and major life stressors, better physical and mental health, and fewer comorbidities than respondents in the 3 clinical groups, and these differences were both statistically significant and substantial. Respondents with IBS reported fewer traumatic and major life stressors and better health (ratings and comorbidity data) than respondents with FM or respondents with IBS plus FM. Overall, respondents with both diseases reported the worst stressors and physical-mental health profiles and reported more diagnosed medical, pain, and psychiatric comorbidities.
Conclusion: The results revealed statistically significant, relatively large differences in perceptions of quality of life measures and health profiles among the respondents in the control group and the 3 clinical groups.
Physicians routinely encounter patients with functional pain disorders, which often present complex treatment challenges. Two common and frequently studied functional pain disorders are irritable bowel syndrome (IBS) and fibromyalgia (FM).
1-3 Although formal diagnostic criteria have been published, both syndromes lack objective findings and, generally, the diagnosis is made on the basis of patient's self-reported symptoms.
4,5 Irritable bowel syndrome is characterized by chronic abdominal pain with altered bowel function,
4 whereas FM is a disease of chronic widespread pain and pain in at least 11 of 18 predetermined tender points.
5 In some studies,
6-8 patients with IBS and patients with FM reportedly have similar psychosocial, medical, and psychiatric profiles, and in several community and clinical studies,
9-12 a substantial number of patients have comorbid IBS and FM. Both diseases occur in approximately one-third of patients
2 when either IBS or FM is the primary diagnosis.
13 Given the striking prevalence of comorbidity and similarities among individuals with these diseases, many investigators have hypothesized shared pathologic charactertistics
3-14 but with only partial success
15-19 at generating a unified explanation.
One study
20 reported patients with comorbid IBS and FM who scored lower on several indices (global feeling of wellness, sleep, anxiety, number of tender points, sense of coherence, concerns about illness and severity) than patients with IBS only and patients in a control group.
20 Similarly, patients with comorbid IBS and FM report lower health-related quality of life scores and more tender points than patients with IBS or FM and control group.
13-21 These results suggest that patients with both IBS and FM are more ill with a diminished quality of life than patients with either disease alone or control patients.
In many studies,
22-25 researchers have demonstrated the co-occurrence of IBS, FM, and psychiatric illnesses, which has generally been associated with more severe symptoms and less favorable outcomes. Moreover, traumatic events are associated with both increased prevalence and worse outcomes of IBS and FM; however, to our knowledge, no common interpretation has emerged.
26-29
In previous research,
20-29 patients with IBS have been compared with patients with comorbid IBS and FM, but these comparisons never have included patients with FM only; nor did past studies evaluate more comprehensive indices, such as perceived general medical, pain, and psychiatric comorbidities. Such comparison might reveal a progressively worsening disease burden among these groups. In the present study, we include 3 clinical groups and compare self-reported perceptions of respondents' medical and mental health. The use of self-reported information may reveal differences in how patients understand these diseases and in how they perceive their disease burden. These individual perceptions may yield insight into a possible underlying process that contributes to disease progression and ultimately may contribute to more effective treatments for patients with these diseases. Specifically, we compared 4 groups of women drawn from the same population—controls (no IBS or FM), those with IBS only, FM only, and both IBS and FM—on the following self-reported measures: physical health and symptoms; mental health assessments; medical-pain-psychiatric comorbidities; and traumatic and major life stressor experiences. We hypothesized that respondents with neither disorder would report better perceived physical and mental health and fewer perceived stressful events than respondents in the 3 clinical groups. We further predicted that, with the exception of gastrointestinal symptoms, self-reported health scores and stress profile scores would worsen, respectively, from IBS to FM to respondents with both disorders.
We evaluated a number of variables from the BRHS questionnaire. The selected variables were neither entirely independent nor redundant. We chose to be overinclusive, however, to facilitate comparisons among clinical data (eg, continuous measure of depression severity and a clinical diagnosis of depression in one's lifetime). Listed first are the continuous physical-mental health variables, followed by the categorical (in all instances, yes/no) variables.
Physical Health—To measure physical health, we used body mass index (BMI); interpretive score ranges were obese (>30), overweight (25-29.9), and normal (18.5-24.9). We also used the Short Form-12, version 2 (SF-12v2) physical health composite
32 for an overall assessment of physical health. Scores ranged from 0 (lowest health level) to 100 (highest health level).
Body pain was measured by means of respondents' answers to the SF-12v2 question “During the past 4 weeks, how much did pain interfere with your normal work (including both work outside the home and housework)?”
32 Ratings were on a 5-point scale, ranging from 1 (not at all) to 5 (extremely).
Physical Symptoms—Physical symptom frequency in the past month
33 was assessed by means of questions about how frequently respondents experienced headache, indigestion, constipation/diarrhea, and incontinence (ie, problem controlling urine or bowel movements). Each was rated on a 5-point scale: 1 (never), 2 (once), 3 (2-3 times), 4 (4-5 times), and 5 (>5 times) in the past month.
Sleep Quality—Sleep quality was assessed on the basis of averaged ratings of 3 items: trouble falling asleep, waking in the middle of the night with difficulty going back to sleep, and waking up very early with difficulty going back to sleep. Items were rated on a 4-point scale, from 1 (almost every day) to 4 (rarely or never). Lower scores indicated poor sleep quality and higher scores indicated good sleep quality. Total scores were expressed as mean (standard deviation [SD]) of available items (1 missing item was allowed).
Mental Health—We used the SF-12v2 mental health composite score
32 to assess overall mental health. Scores ranged from 0 (lowest mental health level) to 100 (highest level). For depressive symptom severity, we used the 11-item Center for Epidemiological Studies-Depression Scale (CES-D). Items are rated on a 3-point scale: 0, none/rarely; 1, occasionally or a moderate amount; and 2, most/all of the time. Scores were reported as the mean (SD) of completed items (2 missing items were allowed). Total scores were transformed to full 20-item CES-D equivalent scores
34; scores greater than or equal to 16 may reflect clinical depression (a cut-point for screening, not diagnostic, purposes).
To assess neuroticism, we used the 8-item Big Five Inventory Neuroticism Scale.
35 This scale assessed psychological functioning in the past month. Items were rated on a 7-point scale (modified from the original 5-point scale), ranging from “not true” (1) to “very true”(7). Total score was expressed as mean (SD) of completed items (1 missing item was allowed).
Medical-Pain-Psychiatric Diagnoses: Comorbidities—Medical, pain, and psychiatric diagnoses were binary variables (yes=1, no=0) from responses to a section that began with, “Mark the bubbles below to show which conditions/diseases you have ever had diagnosed by a physician.” The medical diagnoses included angina pectoris, asthma, type 2 diabetes mellitus, hypertension, hypothyroidism, and sleep apnea. The pain diagnoses were degenerative arthritis, degenerative disk disease, sciatica/arthritic back, and rheumatoid arthritis. The psychiatric diagnosis was depression.
Trauma and Major Life Stressors—Trauma and major life stress items were adapted from the Trauma Assessment in Adults scale and Ryff and colleagues' child abuse scales.
36-38 Respondents were asked about “different types of stressful or difficult life events.” We classified the items as either traumatic experiences or major life stressors. The traumatic experiences are those that likely involved death threats, witnessing another person's death, threats of serious injury, or threats to physical integrity that elicited intense reactions, such as fear, helplessness, or horror.
39-41 We then grouped the items by trauma type:
-
Life-threatening (4 questions regarding war, “really bad” accident [thoughts of death or severe injury], natural disaster, or witnessing someone seriously injured or killed)
-
Emotional abuse or neglect (2 questions about “mother/woman who raised you” or “father/man who raised you” insulting, swearing at, or ignoring when respondents were between ages 5 and 15 years)
-
Physical assault or abuse (2 assault questions, actual and threatened in participant's lifetime; 4 abuse questions from when respondents were between ages 5 and 15 years, mother or father pushing, slapping, throwing objects, kicking, biting, striking with an object)
-
Sexual assault/abuse (3 questions regarding actual and threatened events in one's lifetime)
The major life stressors (single yes/no items) were serious illness (eg, cancer, leukemia, AIDS, multiple sclerosis), abortion (for self or intimate partner), miscarriage (for self or intimate partner), divorce or separation, homelessness, and death of a child. For each of these 5 trauma and stressor variables, respondents were scored 0 points in the category if all responses were “no/never” and were scored 1 point if they answered “yes” to any of the questions in the category.
There were 3811 respondents who met the study criteria. Women in the control group, the IBS group, the FM group, and the IBS plus FM group numbered 3213 (84.3%), 366 (9.6%), 161 (4.2%), and 71 (1.9%), respectively, with a mean (SD) age of 62.4 (13.6), 64.9 (13.7), 63.2 (10.8), and 61.1 (10.9) years, respectively.
Table 3 shows the sample numbers and means (SDs) for the continuous physical health and symptoms, sleep quality, and mental health measures. All overall 1-way ANOVA tests were statistically significant. With 2 exceptions, women in the control group reported better physical and mental health, less pain, fewer physical symptoms, and better sleep quality, as determined by post hoc pairwise tests. Differences in mean BMI between the control group (26.4) and the IBS group (27.0) and mean (SD) incontinence scores between the control group and the FM group (1.7 [1.3] for both groups) were not statistically significant. The mean physical health composite score for women aged 55 to 64 years in the normative sample was 46.28. The mean mental health composite score for the same population in the normative sample was 50.14.
Table 3.
Physical Health and Symptoms, Sleep Quality, and Mental Health Scores of Women in the Control Group and Women With Irritable Bowel Syndrome, Fibromyalgia, or Both Disorders (N=3811)a
| Control (n=3213) | IBS (n=366) | FM (n=161) | IBS+FM (n=71) |
Variable | n | Mean (SD) | n | Mean (SD) | n | Mean (SD) | n | Mean (SD) |
Physical Health | | | | | | | | |
SF-12 physical healthb-f | 2950 | 48.6 (11.0) | 330 | 43.5 (12.4) | 145 | 37.1 (12.8) | 65 | 34.9 (13.1) |
SF-12 body painb-f | 3187 | 1.9 (1.1) | 357 | 2.4(1.2) | 159 | 3.2 (1.3) | 71 | 3.3 (1.2) |
Body mass indexc-f | 3203 | 26.4 (6.3) | 362 | 27.0 (6.4) | 159 | 29.0 (7.5) | 71 | 29.8 (9.1) |
Physical Symptoms | | | | | | | | |
Headachesb-d,f,g | 3190 | 2.3 (1.3) | 361 | 2.8 (1.3) | 160 | 2.8 (1.4) | 71 | 3.3 (1.4) |
Indigestionb-g | 3179 | 2.0 (1.2) | 355 | 2.9 (1.4) | 161 | 2.5 (1.4) | 67 | 3.5 (1.4) |
Constipation/diarrheab-g | 3157 | 1.8 (1.1) | 354 | 2.9 (1.5) | 161 | 2.0(1.3) | 69 | 3.5 (1.5) |
Incontinenceb,d,e,g | 3161 | 1.7 (1.3) | 358 | 2.4(1.6) | 157 | 1.7 (1.3) | 71 | 2.5 (1.6) |
Sleep | | | | | | | | |
Sleep qualityb-d | 3187 | 3.3 (0.7) | 358 | 3.0 (0.8) | 159 | 3.0 (0.8) | 71 | 2.9 (0.8) |
Mental Healthb-d,f,g | | | | | | | | |
SF-12 mental health | 2950 | 52.5 (8.9) | 330 | 50.0 (9.4) | 145 | 50.3 (11.5) | 65 | 46.7 (10.4) |
Depressive symptoms | 3196 | 9.1 (8.5) | 364 | 12.8 (9.9) | 161 | 14.4 (10.1) | 71 | 18.7 (10.5) |
Neuroticism | 3190 | 24.0 (8.9) | 363 | 27.2 (9.0) | 161 | 26.1 (9.3) | 71 | 30.8 (9.6) |
Table 3.
Physical Health and Symptoms, Sleep Quality, and Mental Health Scores of Women in the Control Group and Women With Irritable Bowel Syndrome, Fibromyalgia, or Both Disorders (N=3811)a
| Control (n=3213) | IBS (n=366) | FM (n=161) | IBS+FM (n=71) |
Variable | n | Mean (SD) | n | Mean (SD) | n | Mean (SD) | n | Mean (SD) |
Physical Health | | | | | | | | |
SF-12 physical healthb-f | 2950 | 48.6 (11.0) | 330 | 43.5 (12.4) | 145 | 37.1 (12.8) | 65 | 34.9 (13.1) |
SF-12 body painb-f | 3187 | 1.9 (1.1) | 357 | 2.4(1.2) | 159 | 3.2 (1.3) | 71 | 3.3 (1.2) |
Body mass indexc-f | 3203 | 26.4 (6.3) | 362 | 27.0 (6.4) | 159 | 29.0 (7.5) | 71 | 29.8 (9.1) |
Physical Symptoms | | | | | | | | |
Headachesb-d,f,g | 3190 | 2.3 (1.3) | 361 | 2.8 (1.3) | 160 | 2.8 (1.4) | 71 | 3.3 (1.4) |
Indigestionb-g | 3179 | 2.0 (1.2) | 355 | 2.9 (1.4) | 161 | 2.5 (1.4) | 67 | 3.5 (1.4) |
Constipation/diarrheab-g | 3157 | 1.8 (1.1) | 354 | 2.9 (1.5) | 161 | 2.0(1.3) | 69 | 3.5 (1.5) |
Incontinenceb,d,e,g | 3161 | 1.7 (1.3) | 358 | 2.4(1.6) | 157 | 1.7 (1.3) | 71 | 2.5 (1.6) |
Sleep | | | | | | | | |
Sleep qualityb-d | 3187 | 3.3 (0.7) | 358 | 3.0 (0.8) | 159 | 3.0 (0.8) | 71 | 2.9 (0.8) |
Mental Healthb-d,f,g | | | | | | | | |
SF-12 mental health | 2950 | 52.5 (8.9) | 330 | 50.0 (9.4) | 145 | 50.3 (11.5) | 65 | 46.7 (10.4) |
Depressive symptoms | 3196 | 9.1 (8.5) | 364 | 12.8 (9.9) | 161 | 14.4 (10.1) | 71 | 18.7 (10.5) |
Neuroticism | 3190 | 24.0 (8.9) | 363 | 27.2 (9.0) | 161 | 26.1 (9.3) | 71 | 30.8 (9.6) |
×
Table 2 displays sample numbers and percentages for the medical, pain, and psychiatric diagnoses and trauma/stressor variables (all categorical or yes/no). All overall χ
2 tests were statistically significant. With the exception of type 2 diabetes mellitus and rheumatoid arthritis, the control group showed statistically significant lower rates of general medical, pain, and psychiatric diagnoses than the IBS group. The percentage point differences were substantial, particularly between the control group and the IBS plus FM group. The widest percentage point differences were recorded for hypothyroidism (16.1% [control] and 52.2% [IBS plus FM]) and sleep apnea (3.8% [control] and 24.6% [IBS plus FM]).
Compared with the FM group, the control group reported lower rates of physical, sexual, and emotional trauma and lower major life stressor rates than those in the FM group (range, 10.2%-15.7%). Except in the category of type 2 diabetes mellitus, the control group reported lower rates of general medical, pain, and psychiatric diagnoses than the FM group.
Comparisons across all variables between the control and FM groups and the control and IBS plus FM groups were similar, with 2 exceptions. We observed no statistically significant differences between the control and IBS plus FM groups for variables in the emotional abuse/neglect category and for rheumatoid arthritis rates. There were no statistically significant differences between the control and IBS groups for the trauma/major life stressor variables.
The differences in self-reported physical and mental health problems, comorbidities, and stressors between women in the control and clinical groups were substantial. Moreover, there was an increase in self-reported disease burden for women with FM, who reported more illness and more comorbidities than women with IBS (with the exception of gastrointestinal symptoms). Moreover, women with both disorders self-reported more overall disease burden than women in the IBS or FM groups.
Two previous clinical studies
20,21 reported less severe illness for patients with IBS as measured by health-related quality of life scores and number of tender points than for patients with IBS plus FM but more severe illness than for those in a control group. In another clinical study,
13 patients with IBS plus FM were less severely ill as measured by number and severity of symptoms than patients with IBS or FM or those in the control group. Overall, our respondents' self-reports parallel these findings. Variation within groups in disease burden is common for patients with IBS and FM. Patients with IBS, for example, are heterogeneous in disease manifestations. As reported by 3 studies,
12,13,21 some patients meet diagnostic criteria for IBS but are able to cope adequately and do not have to seek medical care, whereas others are less able to cope, are more ill, and seek medical care. Patients with FM also experience a wide range of pain, stiffness, distress, and restrictions, as reported by other studies.
43,44 Our data demonstrated substantial differences in overall perceived disease burden.
In the present study, respondents in each clinical group perceived themselves as more ill than the control group and disease burden perceptions worsened progressively from IBS to FM to IBS plus FM. Future studies may investigate how this apparent perceived disease burden may contribute to a patient's overall health status.
In general, pain-related diagnoses—whether typically made by means of objective findings (eg, osteoarthritis, degenerative disk disease, sciatica/arthritic back) or, as with IBS and FM, dependent on self-reported criteria (eg, headaches)—also increased progressively across groups. The only exception was rheumatoid arthritis, with a slightly increased rate seen in the FM group. An increase in headaches was expected, but we did not expect to find an increase in self-reported nonfunctional pain disorders that paralleled the frequency and severity of self-reported functional pain-related disorders. There is no obvious explanation for the finding or for any common causal relationship, and, although we are cautious in our interpretation, we view this finding as interesting and worthy of further study. Subsequent investigations may reveal that patients with functional pain disorders attend to physical and psychological symptoms in a progressive manner. This may reveal a common underlying pathology, which increases across groups in the present study.
A consistent increased frequency in the self-reported medical diagnoses of hypothyroidism, hypertension, asthma, angina pectoris, and sleep apnea was seen across all 4 groups. Although these diagnoses are self-reported, there is a consistent pattern to our findings. Respondents with IBS plus FM report more functional, psychiatric, pain-related, and general medical diagnoses than the other groups, and higher scores were reported by the control group, followed by the IBS, FM, and IBS plus FM groups. Such consistency makes it difficult to argue that functional disorders are simply psychiatric or somatic complaints. These findings underscore the need to search for an underlying process.