Epidemiology of ischaemic colitis

Influence of splanchnic artery stenosis on the in-hospital clinical course of elderly patients

BACKGROUND

Chronic mesenteric ischaemia (CMI) has a long asymptomatic period, but little is known about the clinical implications of this phase of the disease, particularly in the elderly, who are most exposed to the condition.

AIMS

The aim of the present observational study was to survey the in-hospital clinical course of elderly patients during the non-specific phase of the disease due to occlusion of at least one splanchnic artery.

METHODS

For a median of 29 months, we followed up 85 patients aged 65 and over who, for various clinical reasons, had undergone computed tomographic and magnetic resonance angiography during 2010 at Padua Teaching Hospital, assessing economic impact and reasons for admission.

RESULTS

Thirty-four of these patients had at least one occluded artery, and 68 % of them had at least one hospital admission. Elderly CMI patients were characterised by a higher number of admissions (median 2 vs 1 p = 0.05) and a higher cost (6044 vs 1733 Euros p = 0.04), but did not present typical gastrointestinal symptoms. The higher number of hospital admissions was not due to specific clinical risks (admitting wards: general medicine: 32 vs 29 %, p = 0.77; general surgery 8 vs 14 %, p = 0.73; vascular surgery: 26.5 vs 20 %, p = 0.46).

CONCLUSIONS

In the asymptomatic phase of CMI, hospitalised elderly patients with at least one occluded splanchnic artery can be subject to a more challenging in-hospital clinical course.

The Zelnorm epidemiologic study (ZEST): a cohort study evaluating incidence of abdominal and pelvic surgery related to tegaserod treatment

Background

Pre-marketing clinical studies of tegaserod suggested an increased risk of abdominal surgery, particularly cholecystectomy. We sought to quantify the association between tegaserod use and the occurrence of abdominal or pelvic surgery, including cholecystectomy.

Methods

This cohort study was conducted within an insured population. Tegaserod initiators and similar persons who did not initiate tegaserod were followed for up to six months for the occurrence of abdominal or pelvic surgery. Surgical procedures were identified from health insurance claims validated by review of medical records. The incidence of confirmed outcomes was compared using both as-matched and as-treated analyses.

Results

Among 2,762 tegaserod initiators, there were 94 abdominal or pelvic surgeries (36 gallbladder): among 2,762 comparators there were 134 abdominal or pelvic surgeries (37 gallbladder) (hazard ratio HR] = 0.70, 95% confidence interval [C.I.] = 0.54-0.91 overall, HR = 0.98, 95% C.I. = 0.62-1.55 for gallbladder). Current tegaserod exposure compared to nonexposure was associated with a rate ratio [RR] of 0.68 (95% C.I. = 0.48-0.95) overall, while the RR was 0.99 (95% C.I. = 0.56-1.77) for gallbladder surgery.

Conclusions

In this study, tegaserod use was not found to increase the risk of abdominal or pelvic surgery nor the specific subset of gallbladder surgery.

The risk of ischaemic colitis in irritable bowel syndrome patients treated with serotonergic therapies

Ischaemic colitis (IC) is the most common form of ischaemic injury to the gastrointestinal (GI) tract. IC typically presents with the sudden onset of lower abdominal pain, cramping and rectal bleeding, and is usually self-limited with low morbidity, although it may cause gangrenous or fulminant colitis, especially when the right colon is involved. Multiple medical conditions, as well as several pharmacological agents, are associated with IC, including irritable bowel syndrome (IBS) and drugs used for its treatment that act on gut serotonin 5-HT receptors. These include the selective 5-HT(3) receptor antagonist alosetron, currently approved for the treatment of severe diarrhoea-predominant IBS in women who fail to respond to conventional treatment, and cilansetron, another 5-HT(3) receptor antagonist that is no longer in clinical development. In addition, the 5-HT(4) receptor partial agonist tegaserod, which was approved for the treatment of constipation-predominant IBS in women, was associated with IC in the postmarketing setting, as was renzapride, a 5-HT(4) agonist/5-HT(3) antagonist. Although several hypotheses have been proposed, the pathophysiological basis for development of IC with 5-HT(3) receptor antagonists or 5-HT(4) receptor agonists remains unknown. Of interest, several population-based studies demonstrated that a diagnosis of IBS (independent of serotonergic therapies) increases the risk of developing IC 2- to 4-fold. As a result, IBS patients with the acute onset of abdominal pain, tenderness, diarrhoea or lower intestinal bleeding, especially those with predisposing conditions or medications, should be evaluated promptly for IC. The management of IC remains supportive; most cases of non-gangrenous IC, as seen in the alosetron and tegaserod databases, have been transient and have resolved spontaneously without complications or death. Despite the small number of deaths associated with alosetron in patients with complications of constipation and because of the ongoing requirement to prescribe alosetron under a risk management plan, misconceptions persist regarding the definition, incidence, severity and outcome of IC in clinical trials and the postmarketing setting. In this article, the frequency and clinical characteristics of IC associated with the use of alosetron and other serotonergic agents are examined, evidence of an association between IC and IBS is reviewed, and a scoring system to aid in the diagnosis of IC in any clinical situation is proposed.

Risk factors for intestinal ischaemia among patients registered in a UK primary care database: a nested case-control study

BACKGROUND

Intestinal ischaemia, including ischaemic colitis and acute mesenteric ischaemia, causes significant morbidity and mortality. Few population-based studies have estimated incidence and potential risk factors for this disease.

AIMS

To estimate the incidence of intestinal ischaemia and identify the associated risk factors in cohorts: (i) patients with irritable bowel syndrome and/or chronic constipation (IBS/CC/both), (ii) individuals free of these conditions.

METHODS

Population-based case-control analysis nested in a cohort of patients with first ever recorded diagnosis of IBS/CC/both and a cohort free of these conditions from general population using the General Practice Research Database.

RESULTS

Of 78 cases of intestinal ischaemia, 71 were from general population, seven from the IBS/CC/both cohort. Incidence rate of intestinal ischaemia in IBS/CC/both patients vs. general population was 4.49:1.09 per 100,000 person-years; age- and gender-adjusted incidence rate ratio (95% CI) was 2.7 (1.2-5.9). Inflammatory bowel disease and heart failure showed an association with ischaemic colitis [OR (95% CI): 4.2 (0.5-38.4) and 5.6 (2.2-14.1)], but none with acute mesenteric ischaemia. Diabetes and prior cardiovascular surgery were associated with higher risk of acute mesenteric ischaemia, but showed no association with ischaemic colitis.

CONCLUSIONS

Results suggest that different risk factors are associated with acute mesenteric ischaemia and ischaemic colitis. However, due to small number of patients, associations should be carefully interpreted.

An observational study of cholecystectomy in patients receiving tegaserod

BACKGROUND

Registrational studies of patients treated with tegaserod for irritable bowel syndrome (IBS) suggest an increased risk for cholecystectomy versus treatment with placebo.

OBJECTIVE

To study cholecystectomy rates in association with tegaserod within a large administrative medical claims database.

METHODS

Patients were drawn from a large population within the US with commercial medical insurance. The primary analysis consisted of a comparison of the observed incidence rate for cholecystectomy claims among a large cohort of new-to-therapy tegaserod users with an incidence rate published for tegaserod-naive patients classified with IBS within the same insured population.

RESULTS

An inception cohort of 7475 individuals with up to 103 weeks of claims history following initiation of therapy with tegaserod was identified. After a follow-up of 3 months (and thus similar to the longest registrational trials), the observed cholecystectomy incidence rate was 340 per 10,000 person-years (95% CI 258, 442). The rate of cholecystectomy was highest in the earliest months of observation following initiation of tegaserod. The observed cholecystecomy incidence rate is 2.9 times higher than an IBS-specific rate of 119 per 10,000 person-years as published for patients so classified within the same insured population.

CONCLUSION

Based on a large, inception cohort, we report a strong temporal association between the initiation of tegaserod therapy and an increased rate for cholecystectomy. The effect size at 3 months was similar to the relative risk for cholecystectomy reported in registrational studies comparing tegaserod with placebo. As misclassification of initial diagnosis for patients presenting with biliary colic-like symptoms may occur, precise measurements of tegaserod-related relative risk for cholecystectomy from observational studies are problematic and will require prospective studies.

Alosetron: ischemic colitis and serious complications of constipation

Drugs such as alosetron that modulate serotonin effects by stimulating or blocking its receptors may play an important role in the treatment of some patients with irritable bowel system. In the case of alosetron, a 5HT-3 antagonist, an analysis of data from randomized clinical trials and postmarketing experiences have demonstrated a causal relationship between this drug and ischemic colitis and serious complications of constipation. Because the mechanism(s) of drug-induced ischemic colitis and possibly other forms of intestinal ischemia associated with alosetron have not been elucidated, there is need to further assess risk with regard to patient susceptibility and other factors.