The Spectrum of Constipation-Predominant IBS
The Spectrum of Constipation-Predominant IBS
This study assessed the symptom profile, symptom burden, and disease burden in individuals who met the Rome III criteria for IBS-C or CIC (Rome III criteria use the term functional constipation). For each of the symptoms evaluated in the study (five abdominal symptoms and seven bowel symptoms), the frequency and bothersomeness were significantly greater in the IBS-C respondents than in the CIC respondents.
Among the CIC respondents, the symptoms experienced with the highest frequencies were constipation, straining, and hard/lumpy stool. Also, notable among the CIC respondents, the mean frequencies for the abdominal symptoms of bloating, gas pain, abdominal discomfort, and abdominal pain were each greater than once per week. The reporting of abdominal symptoms in the CIC respondents is consistent with earlier studies that have quantified the presence of abdominal symptoms among CIC patients.
In considering reports of abdominal symptoms in CIC patients, it is important to note that, according to the Rome III diagnostic criteria, the diagnosis of CIC (or functional constipation) excludes any patient who meets the criteria for IBS. The criterion for IBS, with symptom onset ≥6 months before diagnosis, is recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months that is associated with at least two of the following three conditions: (i) the pain or discomfort is improved with defecation, (ii) the onset of the pain or discomfort is associated with a change in stool frequency, and (iii) the onset of the pain or discomfort is associated with a change in the form of stool. Aside from the exclusion of IBS diagnoses, the Rome III criteria for CIC (or functional constipation) do not address abdominal symptoms.
In keeping with the Rome III diagnostic criteria, the IBS and CIC respondents in this study were mutually exclusive groups. Two points are important to emphasize regarding the distinction between the IBS-C and CIC-A groups identified in this study. Although CIC respondents may have reported experiencing abdominal pain or discomfort at a frequency at or above the Rome III IBS frequency threshold, they were necessarily excluded from the IBS group if they did not report at least two of the three required conditions associating pain/discomfort with bowel habits. Also, for the CIC-A group, any combination of abdominal symptoms (cramping and bloating in addition to pain and discomfort) could have been reported at a frequency of more than once per week.
To explore the impact of abdominal symptoms in CIC, we analyzed the CIC respondents in two groups: those who reported experiencing at least one abdominal symptom (abdominal pain, abdominal discomfort, stomach cramping, and/or bloating) at least once per week and those who did not. Of the 552 CIC respondents, 363 experienced abdominal symptoms at least once per week and 189 did not. For the CIC respondents with abdominal symptoms, the bothersomeness of all symptoms (bowel as well as abdominal) was significantly greater compared with the bothersomeness experienced by the CIC respondents without abdominal symptoms. Comparing the IBS-C respondents and the CIC respondents with abdominal symptoms, the bothersomeness of each symptom appeared to be greater in the IBS-C respondents, with 5 of the 12 symptoms—abdominal discomfort, bloating, constipation, straining, and pellet-like stools—statistically significantly more bothersome in IBS-C compared with CIC with abdominal symptoms.
The reports of bothersomeness suggest that the presence of abdominal symptoms in CIC patients may affect patients' overall symptom experience and may be associated with increased intensity of bowel symptoms. The study findings are consistent with a recent analysis of two phase 3 clinical trials in patients meeting the Rome II criteria for CIC that concluded that, in CIC patients with abdominal pain, it is the abdominal symptoms rather than the bowel symptoms alone that may drive patient assessment of constipation severity, HRQOL, and overall response to treatment.
Several studies have established the impact of IBS on HRQOL, with IBS patients consistently scoring lower than non-IBS patients. Physical HRQOL in IBS is the same or lower when compared with HRQOL in diabetes, depression, and gastroesophageal reflux disease, whereas mental HRQOL is lower than in patients with chronic renal failure. Recently published studies have shown that IBS-C and CIC are associated with substantial disease burden, in terms of both overall costs and HRQOL. An economic-burden analysis found that patients with IBS-C incurred significantly higher health-care costs that were nearly double that of matched controls and similar in magnitude to costs of other chronic conditions such as migraine and asthma. An analysis of health-care costs in CIC patients found direct health-care costs to be significantly higher compared with matched controls; the analysis also found the costs to be significantly higher for CIC patients with abdominal symptoms compared with costs for those without abdominal symptoms.
Our study assessed disease burden in terms of missed days and disrupted productivity. Missed days due to GI symptoms were similar in IBS-C and CIC respondents with abdominal symptoms and somewhat less in CIC respondents without abdominal symptoms; the difference between the two CIC groups, those with abdominal symptoms and those without, did not reach statistical significance. Productivity was disrupted due to GI symptoms significantly more in the IBS-C respondents when compared with each CIC group; productivity disruption was also significantly greater in CIC with abdominal symptoms when compared with CIC respondents without abdominal symptoms.
Among the three groups analyzed in the study, the IBS-C respondents were the most likely to seek physician evaluation for GI symptoms (52%), followed by CIC respondents with abdominal symptoms (43%) and followed in turn by CIC respondents without abdominal symptoms (34%). These results are consistent with those of a population-based survey in Spain that found that approximately 40% of chronic constipation respondents sought medical care for constipation and that seeking medical care was correlated with the symptoms of abdominal pain and prolonged defecation. In addition to assessing health-care-seeking behavior, our survey assessed satisfaction with the physician care that respondents received. The IBS-C and CIC patients with abdominal symptoms were significantly less likely to be very or extremely satisfied with their care than CIC patients without abdominal symptoms.
This study is a post-hoc analysis of a cross-sectional population survey, reflecting respondents' retrospective assessment of symptom experience, bothersomeness, and symptom frequency at a single point in time. An inherent limitation is that respondents reported symptoms based on a list of individual symptoms; the responses do not reflect how patients may experience symptoms in conjunction with one another, nor do they reflect how respondents may experience or define individual symptoms (e.g., the term "stomach cramping" may, to some, specifically indicate gastric pain, whereas to others it may be a general cramping; patients may or may not experience gas and bloating as two distinct symptoms).
The study findings highlight the substantial burden of IBS-C and CIC, centered on the impact of the bothersomeness of these diseases, resulting in decreased work productivity and increased physician-seeking care. Furthermore, the severity and impact of disease appears to be greatest in the IBS-C population and greater in the CIC respondents with weekly abdominal symptoms than in the CIC respondents without weekly abdominal symptoms. In total, our data suggest that patient-reported disease severity tracks closely with the presence or absence of abdominal symptoms. Therefore, the presence of abdominal symptoms may provide a proxy for disease severity along a continuum. This notion of a spectrum of disease severity is consistent with observations expressed in recent literature that, despite the research value for treating the mutually exclusive diagnostic categories of IBS-C and CIC established by the Rome III criteria, in clinical practice there is not necessarily a clear separation between the two disorders, with many patients migrating between the diagnoses over time. It is this view that prompted the American College of Gastroenterology's Task Force on the management of functional bowel disorders to revise its approach and review treatments for IBS-C and CIC within one integrated clinical framework. Viewing these two disorders as part of a spectrum of disease severity conveys the clinical value of considering the full range of symptoms in IBS-C and CIC that patients may experience.
Discussion
This study assessed the symptom profile, symptom burden, and disease burden in individuals who met the Rome III criteria for IBS-C or CIC (Rome III criteria use the term functional constipation). For each of the symptoms evaluated in the study (five abdominal symptoms and seven bowel symptoms), the frequency and bothersomeness were significantly greater in the IBS-C respondents than in the CIC respondents.
Among the CIC respondents, the symptoms experienced with the highest frequencies were constipation, straining, and hard/lumpy stool. Also, notable among the CIC respondents, the mean frequencies for the abdominal symptoms of bloating, gas pain, abdominal discomfort, and abdominal pain were each greater than once per week. The reporting of abdominal symptoms in the CIC respondents is consistent with earlier studies that have quantified the presence of abdominal symptoms among CIC patients.
In considering reports of abdominal symptoms in CIC patients, it is important to note that, according to the Rome III diagnostic criteria, the diagnosis of CIC (or functional constipation) excludes any patient who meets the criteria for IBS. The criterion for IBS, with symptom onset ≥6 months before diagnosis, is recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months that is associated with at least two of the following three conditions: (i) the pain or discomfort is improved with defecation, (ii) the onset of the pain or discomfort is associated with a change in stool frequency, and (iii) the onset of the pain or discomfort is associated with a change in the form of stool. Aside from the exclusion of IBS diagnoses, the Rome III criteria for CIC (or functional constipation) do not address abdominal symptoms.
In keeping with the Rome III diagnostic criteria, the IBS and CIC respondents in this study were mutually exclusive groups. Two points are important to emphasize regarding the distinction between the IBS-C and CIC-A groups identified in this study. Although CIC respondents may have reported experiencing abdominal pain or discomfort at a frequency at or above the Rome III IBS frequency threshold, they were necessarily excluded from the IBS group if they did not report at least two of the three required conditions associating pain/discomfort with bowel habits. Also, for the CIC-A group, any combination of abdominal symptoms (cramping and bloating in addition to pain and discomfort) could have been reported at a frequency of more than once per week.
To explore the impact of abdominal symptoms in CIC, we analyzed the CIC respondents in two groups: those who reported experiencing at least one abdominal symptom (abdominal pain, abdominal discomfort, stomach cramping, and/or bloating) at least once per week and those who did not. Of the 552 CIC respondents, 363 experienced abdominal symptoms at least once per week and 189 did not. For the CIC respondents with abdominal symptoms, the bothersomeness of all symptoms (bowel as well as abdominal) was significantly greater compared with the bothersomeness experienced by the CIC respondents without abdominal symptoms. Comparing the IBS-C respondents and the CIC respondents with abdominal symptoms, the bothersomeness of each symptom appeared to be greater in the IBS-C respondents, with 5 of the 12 symptoms—abdominal discomfort, bloating, constipation, straining, and pellet-like stools—statistically significantly more bothersome in IBS-C compared with CIC with abdominal symptoms.
The reports of bothersomeness suggest that the presence of abdominal symptoms in CIC patients may affect patients' overall symptom experience and may be associated with increased intensity of bowel symptoms. The study findings are consistent with a recent analysis of two phase 3 clinical trials in patients meeting the Rome II criteria for CIC that concluded that, in CIC patients with abdominal pain, it is the abdominal symptoms rather than the bowel symptoms alone that may drive patient assessment of constipation severity, HRQOL, and overall response to treatment.
Several studies have established the impact of IBS on HRQOL, with IBS patients consistently scoring lower than non-IBS patients. Physical HRQOL in IBS is the same or lower when compared with HRQOL in diabetes, depression, and gastroesophageal reflux disease, whereas mental HRQOL is lower than in patients with chronic renal failure. Recently published studies have shown that IBS-C and CIC are associated with substantial disease burden, in terms of both overall costs and HRQOL. An economic-burden analysis found that patients with IBS-C incurred significantly higher health-care costs that were nearly double that of matched controls and similar in magnitude to costs of other chronic conditions such as migraine and asthma. An analysis of health-care costs in CIC patients found direct health-care costs to be significantly higher compared with matched controls; the analysis also found the costs to be significantly higher for CIC patients with abdominal symptoms compared with costs for those without abdominal symptoms.
Our study assessed disease burden in terms of missed days and disrupted productivity. Missed days due to GI symptoms were similar in IBS-C and CIC respondents with abdominal symptoms and somewhat less in CIC respondents without abdominal symptoms; the difference between the two CIC groups, those with abdominal symptoms and those without, did not reach statistical significance. Productivity was disrupted due to GI symptoms significantly more in the IBS-C respondents when compared with each CIC group; productivity disruption was also significantly greater in CIC with abdominal symptoms when compared with CIC respondents without abdominal symptoms.
Among the three groups analyzed in the study, the IBS-C respondents were the most likely to seek physician evaluation for GI symptoms (52%), followed by CIC respondents with abdominal symptoms (43%) and followed in turn by CIC respondents without abdominal symptoms (34%). These results are consistent with those of a population-based survey in Spain that found that approximately 40% of chronic constipation respondents sought medical care for constipation and that seeking medical care was correlated with the symptoms of abdominal pain and prolonged defecation. In addition to assessing health-care-seeking behavior, our survey assessed satisfaction with the physician care that respondents received. The IBS-C and CIC patients with abdominal symptoms were significantly less likely to be very or extremely satisfied with their care than CIC patients without abdominal symptoms.
This study is a post-hoc analysis of a cross-sectional population survey, reflecting respondents' retrospective assessment of symptom experience, bothersomeness, and symptom frequency at a single point in time. An inherent limitation is that respondents reported symptoms based on a list of individual symptoms; the responses do not reflect how patients may experience symptoms in conjunction with one another, nor do they reflect how respondents may experience or define individual symptoms (e.g., the term "stomach cramping" may, to some, specifically indicate gastric pain, whereas to others it may be a general cramping; patients may or may not experience gas and bloating as two distinct symptoms).
The study findings highlight the substantial burden of IBS-C and CIC, centered on the impact of the bothersomeness of these diseases, resulting in decreased work productivity and increased physician-seeking care. Furthermore, the severity and impact of disease appears to be greatest in the IBS-C population and greater in the CIC respondents with weekly abdominal symptoms than in the CIC respondents without weekly abdominal symptoms. In total, our data suggest that patient-reported disease severity tracks closely with the presence or absence of abdominal symptoms. Therefore, the presence of abdominal symptoms may provide a proxy for disease severity along a continuum. This notion of a spectrum of disease severity is consistent with observations expressed in recent literature that, despite the research value for treating the mutually exclusive diagnostic categories of IBS-C and CIC established by the Rome III criteria, in clinical practice there is not necessarily a clear separation between the two disorders, with many patients migrating between the diagnoses over time. It is this view that prompted the American College of Gastroenterology's Task Force on the management of functional bowel disorders to revise its approach and review treatments for IBS-C and CIC within one integrated clinical framework. Viewing these two disorders as part of a spectrum of disease severity conveys the clinical value of considering the full range of symptoms in IBS-C and CIC that patients may experience.
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