Low muscle mass and sarcopenia: common and predictive of osteopenia in inflammatory bowel disease

BACKGROUND

Body composition is poorly studied in inflammatory bowel disease (IBD). Sarcopenia describes a loss of muscle mass and strength.

AIM

To assess the prevalence of low lean mass (LM), sarcopenia and associated morbidity in an adult IBD cohort.

METHODS

Cross-sectional data were gathered on pre-menopausal 18- to 50-year-old patients with IBD. Whole-body dual-energy X-ray absorptiometry, anthropometric assessment and grip strength were performed. Low LM was defined as ≥1 s.d. below the population mean for appendicular skeletal muscle index [ASMI (kg)/height (m)²], and sarcopenia as both ASMI and grip strength ≥1 s.d. below population mean. Multivariate regression analyses were performed.

RESULTS

Of 137 participants (median age 31 years, BMI 24.8 kg/m(2) ), 56% were male and 69% had Crohn's disease (CD). Low LM and sarcopenia were observed in 21% and 12% of patients, respectively, and osteopenia/osteoporosis in 38% of patients (mean lumbar spine t-score -0.3 ± s.d. 1.1). Grip strength predicted low LM and sarcopenia better than did body mass index (BMI) (OR 4.8 vs. OR 0.7 for low-LM, P < 0.05 both). Normal BMI was falsely reassuring in 72% and 76% of patients with low ASMI and sarcopenia, respectively. Low LM and sarcopenia (OR = 3.6, P = 0.03; OR = 6.3, P = 0.02; respectively), but not BMI nor fat mass, predicted osteopenia/osteoporosis.

CONCLUSIONS

Low lean mass and sarcopenia are common in patients with IBD, and important to recognise as they predict osteopenia/osteoporosis. Grip strength testing should be incorporated into routine clinical practice to detect low lean mass deficits, which may go unrecognised using BMI alone.

Systematic review: body composition in adults with inflammatory bowel disease

BACKGROUND

There is a paucity of data on body composition in patients with inflammatory bowel disease (IBD). Alterations of fat and muscle may affect bone health, muscle performance, quality of life (QoL) and overall morbidity.

AIMS

To systematically review the literature on body composition in adults with IBD, and to discuss potential contributory factors and associations.

METHODS

A systematic search was performed in July 2012 of OVID SP MEDLINE, OVID EMBASE and National Library of Medicine's PubMed Central Medline (Limitations: English, humans, from 1992). A total of 19 articles comparing body composition in patients with IBD with healthy age- and sex-matched control populations were included in the primary analysis.

RESULTS

A total of 631 patients with Crohn's disease (CD) and 295 with ulcerative colitis (UC), mean age 37.1 (s.d. ± 9.2) years; 485 (52%) female, were reported upon. Data were heterogeneous and methodology varied. Compared with controls, a statistically significant reduction in body mass index (BMI) was reported in 37% of CD and 20% of UC patients; reduced fat-free mass in 28% CD and 13% UC patients, and reduced fat mass in 31% CD and 13% UC patients. There was no consistent association between body composition and disease activity, duration, extent or therapies. BMI did not accurately predict body composition.

CONCLUSIONS

Current data, although heterogeneous, suggest that many patients with IBD are affected by aberrations in fat and lean mass, which may not be detected during routine clinical assessment. The prevalence and impact of altered body composition amongst this population warrant further investigation.

Use of Technegas as a radiopharmaceutical for the measurement of gastric emptying

Many radiopharmaceuticals and test meals that are used to measure gastric emptying are less than optimal. A vegetable-based solid meal, such as rice, labelled with a radiopharmaceutical that also has the capacity to measure gastric emptying of liquids, is likely to be ideal. The role of Technegas as a radioisotopic marker to measure gastric emptying of rice and liquids was evaluated. Technegas-labelled rice was incubated in 0.9% saline, 1 M HCl and simulated gastric fluid (3.2 g/l pepsinogen, pH 2-3) to assess stability of the label. In eight healthy volunteers gastric emptying of two meals - 200 g rice (370 kcal) and 75 g dextrose dissolved in 300 ml water (300 kcal), both labelled with 20 MBq of Technegas - was measured scintigraphically. Over 4 h, the average label stability was 93.7%+/-0.5% in 0.9% saline, 91.0%+/-0.4% in 1 M HCl and 93.6%+/-0.7% in simulated gastric juice. The lag phase was longer for rice than dextrose (25+/-7 min vs 4+/-2 min; P<0.05), but there was no difference in the post-lag emptying rate (2.1+/-0.3 kcal/min vs 1.7+/-0.2 kcal/min; P=0.2) between the two meals. We conclude that Technegas is a suitable radiopharmaceutical for measurement of gastric emptying of rice and nutrient-containing liquids.

Relation between postprandial satiation and antral area in normal subjects

The factors influencing appetite in humans are poorly understood. There is a weak relation between appetite and gastric emptying in normal subjects. Recent studies have shown that fasting and postprandial antral areas increase in patients with functional dyspepsia compared with normal subjects. We evaluated the hypothesis that antral area, and hence antral distention, is a significant determinant of postprandial fullness. Fourteen normal subjects had simultaneous measurements of gastric emptying by scintigraphy and antral area by ultrasound after ingestion of 350 mL 20% glucose. Fullness and hunger were assessed by visual analog scales. Measurements of the gastric-emptying half time (t1/2) by scintigraphy and ultrasound were not significantly different (129.6 +/- 11.8 min compared with 115.6 +/- 11.4 min). Fullness increased (P < 0.001) and hunger decreased (P < 0.001) after the drink. Both fullness and the magnitude of the increase in fullness after the drink were related to antral area (r > 0.56, P < 0.05), the increase in antral area (r > 0.59, P < 0.05), and the scintigraphic content of the distal stomach (r > 0.57, P < 0.05), but not to the ultrasound or scintigraphic t1/2 values. In contrast, hunger and the magnitude of the decrease in hunger after the drink were not related to either antral area, the increase in antral area, or the rate of gastric emptying. We conclude that postprandial fullness, but not hunger, was closely related to antral distention in normal subjects.

The pharmacokinetics of ketoconazole after chronic administration in adults

We have studied the pharmacokinetics of the anti-mycotic ketoconazole in seven patients who took it for 1-6 months at a dose of 200 mg daily. The mean elimination half-life of the drug was 3.3 h, and although the ketoconazole was given only once daily, a satisfactory clinical response was obtained in all seven individuals. Only a small fraction of the absorbed drug (mean 0.22%) was excreted unchanged in the urine, suggesting almost complete metabolism. Our results support the concept that anti-mycotic activity in the tissues continues after the plasma drug concentration has fallen below a critical level. Our results also support the concept of a change in pharmacokinetics with chronic dosing.

Changes in plasma catecholamine levels during hemodialysis

The plasma concentrations of dopamine (DA), adrenaline (AD) and noradrenaline (NA) were measured during 29 routine hemodialysis (HD) treatments on 13 patients to determine whether any changes occurred in the concentrations of these substances during HD. All of the 13 patients studied demonstrated a fall in mean arterial pressure (MAP) when HD was commenced. Decreased concentrations of all three catecholamines were also demonstrated after the first hour of dialysis. Plasma AD rose after two hours, but NA and DA were still significantly lower than pre-dialysis values at the end of HD. Study of 12 further patients during the first hour of HD confirmed that the NA level had fallen significantly by the fifteenth minute of HD, while the DA and AD levels took somewhat longer to fall. Both NA and DA were present in the dialysate in substantial amounts. Although the fall in MAP which accompanies HD is probably multifactorial, the loss of plasma catecholamines during HD may possibly contribute to the hemodynamic changes.

Sea water. A novel self-medication for orthostatic hypotension

We report the case of a patient who ingested sea water to combat disabling postural hypotension secondary to autonomic failure. While drinking approximately 900 mL of brine each day he had no symptoms and felt well. Serum biochemical analysis showed a very significant hyperchloraemia. Persistent diarrhoea eventually forced the patient to discontinue this most unorthodox form of treatment.