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Letters to the Editor |
Department of Internal Medicine Metabolic Unit, Università Cattolica S Cuore Largo A Gemelli, 8 Rome 00168 Italy E-mail: iclcm{at}rm.unicatt.it
Dear Sir:
We read with great interest the paper by Geerling et al (1) and the related editorial (2) regarding the usefulness of a comprehensive assessment of nutritional status in patients with inactive Crohn disease (CD). In Geerling et al's study, patients with inactive CD were found to have fat and fat-free mass contents (assessed by anthropometry and dual-energy X-ray absorptiometry) similar to those of control subjects. Our group previously reported the importance of studying CD patients during a remission phase because intercurrent factors related to inflammation can severely affect data measurement (3, 4). We found steroid treatment; the presence of clinical symptoms such as diarrhea, abdominal pain, and nausea; and the exclusion of patients who had undergone intestinal resection to be factors of primary importance for a correct evaluation of nutritional status in patients with inflammatory bowel disease (IBD). In addition, we suggested that the measurement of energy balance provides valuable information (5). We showed that CD patients with inactive disease had peculiar metabolic and body-composition features with respect to both control subjects and patients affected by ulcerative colitis (UC), the other major form of IBD. In particular, regardless of disease localization (ileal, ileocolonic, or colonic), patients with inactive CD had reduced fat mass with good preservation of fat-free mass and an enhanced utilization of lipids as a fuel substrate (3–5). This lack of similarity between patients with different IBDs with the same intestinal localization seems to strengthen the hypothesis of peculiar metabolic features in CD (3–5).
The differences between our data and those of Geerling et al could be due to several factors. First, as Geerling et al stated in their methods section, 15 patients (47% of the population examined) had a Crohn's Disease Activity Index >150; thus, although the C-reactive protein value for these patients was within the normal range, they were presumably not in clinical or histologic remission. It would have been of interest to evaluate whether differences existed in any of the variables examined between patients with different disease activity indexes.
Second, to obtain a homogeneous group, none of our patients with inactive CD had undergone intestinal resections because we do not think that patients with or without small-bowel resections can be considered to be similar from nutritional and metabolic points of view. On the contrary, 27 patients in Geerling et al's study (84% of the patient population) underwent an average intestinal resection of 75 cm.
We were surprised by the high lipid intakes reported by CD patients in Geerling et al's study. Subjects with diseases of the gastrointestinal tract usually become able to identify food items that may give rise to intestinal symptoms, such as those containing high amounts of lipids, and avoid them in their diets. Nutritional deficiencies of micro- or macronutrients could then easily occur. In CD, because of major disease symptoms including abdominal pain and nausea, decreased intakes of nutrients have been reported (6). In particular, consumption of energy, calcium, iron, vitamin A, vitamin B-12, and folate was found to be poorest in patients with CD (7). The inclusion of patients with small-bowel resections may have created a bias in energy intake evaluation, independent of disease activity. Moreover, Geerling et al stated that 13 patients (41%) were taking an average daily dose of prednisone of 5 mg. Our group showed recently that glucocorticoid therapy is positively correlated with energy intake in patients with active CD (5).
Finally, according to the difference between energy intake and energy expenditure, which was computed only in mathematical equations by the authors, CD patients seemed to be in positive energy balance (610 kJ/d) whereas control subjects were in negative energy balance (-585 kJ/d). These data suggest that indirect calorimetry assessment of energy requirements along with the measurement of energy loss, essentially with stools, might be of great use in evaluating energy balance, especially in patients with an inflammatory disease characterized by intestinal malabsorption (5). Many patients in Geerling et al's study had liquid stools, indicating increased energy loss.
We therefore suggest that in addition to the measurements given by Geerling et al, a comprehensive assessment of nutritional status in CD patients should include the study of energy requirements, which can be safely done and is easy to perform even in children. The combination of these diagnostic tools would allow clinicians, surgeons, and nutritionists to better manage impairments of nutritional status in these patients and consequently to improve their quality of life (8). In addition, great care should be taken in defining current remission and in choosing a homogeneous group of patients.
REFERENCES
Department of Gastroenterology and Hepatology University Hospital Maastricht PO Box 5800 6202 AZ Maastricht Netherlands E-mail: bgee{at}sint.azm.nl
Dear Sir:
We read with pleasure the letter by Capristo et al and appreciate their comments on our study (1). In a recent study, Capristo et al (2) reported a lower fat mass in patients with Crohn disease (CD) during a remission phase than in control subjects or patients with ulcerative colitis, whereas fat-free mass did not differ significantly between groups. Indeed, we also found a significantly lower fat mass and percentage body fat (measured by dual-energy X-ray absorptiometry) in male patients with long-standing CD currently in remission, in contrast with female CD patients in whom body composition did not differ from that in control subjects. The observed sex differences are interesting and are not often described. Data suggest that there may be sex differences in the efficiency of energy metabolism under metabolic stress. It was reported that daily exercise reduces fat mass, protein mass, and body mass in male but not female rats despite a more negative energy balance in female rats (3).
There is no general agreement regarding the assessment of disease activity in CD. The clinical index most frequently used is the Crohn's Disease Activity Index (CDAI), but its value is widely disputed. Most studies continue to use the CDAI because of the lack of a better index. Many complications of CD elevate the CDAI yet do not reflect active inflammation (4); this was illustrated by the increased stool frequency after small-bowel resection observed in our study. As we pointed out, all patients had stable body weights, no significant acute phase response (ie, normal C-reactive protein values), and no change in medication during the 3 mo preceding the study. This indicated that the patients included in the study were clinically in remission.
Capristo et al suggested that patients with and without small-bowel resection should not be pooled to study nutritional or metabolic changes. However, we were interested in the nutritional status of a representative sample of patients with long-standing CD. Exclusion of patients with small-bowel resections would have greatly impaired the clinical value of such a study. Second, in our opinion there is no essential metabolic difference in small-bowel function between patients with small-bowel resections and those in whom a small-bowel segment has been destroyed as the result of a previous inflammation. In both cases, small-bowel function is impaired, eventually resulting in malnutrition.
In our study, absolute daily fat intake was not significantly different between CD patients (35.1% of energy intake) and matched control subjects (33.6% of energy intake). Patients were clinically in remission and were not anorexic, in contrast with the patients in the study of Rigaud et al (5) who lost weight and reported decreased food intake. Although we did not measure energy metabolism directly, the patients in our study were presumably in energy balance because they all had stable body weights during the 3 mo preceding the study. It would be interesting from a scientific point of view, however, to measure energy expenditure in these patients because this may further our understanding of the pathophysiology of malnutrition in CD. Because of possible differences in daily total energy expenditure between patients and control subjects as a result of quantitative and qualitative differences in daily activities, the predictive value of resting energy expenditure measured by indirect calorimetry is limited. Hence, in this respect, the doubly labeled water technique seems to be the most adequate method (6).
REFERENCES
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