Georg A. Stalder

Performance of panel-based criteria to evaluate the appropriateness of colonoscopy: a prospective study

BACKGROUND Prospective data describing the appropriateness of use of colonoscopy based on detailed panel-based clinical criteria are not available. METHODS In a cohort of 553 consecutive patients referred for colonoscopy to two university-based Swiss outpatient clinics, the percentage of patients who underwent colonoscopy for appropriate, equivocal, and inappropriate indications and the relationship between appropriateness of use and the presence of relevant endoscopic lesions was prospectively assessed. This assessment was based on criteria of the American Society for Gastrointestinal Endoscopy and explicit American and Swiss criteria developed in 1994 by a formal panel process using the RAND/UCLA appropriateness method. RESULTS The procedures were rated appropriate or equivocal in 72.2% by criteria of the American Society for Gastrointestinal Endoscopy, in 68.5% by explicit American criteria, and in 74.4% by explicit Swiss criteria (not statistically significant, NS). Inappropriate use (overuse) of colonoscopy was found in 27.8%, 31.5%, and 25.6%, respectively (NS). The proportion of appropriate procedures was higher with increasing age. Almost all reasons for using colonoscopy could be assessed by the two explicit criteria sets, whereas 28.4% of reasons for using colonoscopy could not be evaluated by the criteria of the American Society for Gastrointestinal Endoscopy (p < 0.0001). The probability of finding a relevant endoscopic lesion was distinctly higher in the procedures rated appropriate or equivocal than in procedures judged inappropriate. CONCLUSIONS The rate of inappropriate use of colonoscopy is substantial in Switzerland. Explicit criteria allow assessment of almost all indications encountered in clinical practice. In this study, all sets of appropriateness criteria significantly enhanced the probability of finding a relevant endoscopic lesion during colonoscopy.

Failure of acyclovir to enhance the antiviral effect of α lymphoblastoid interferon on HBe-seroconversion in chronic hepatitis B: A multi-centre randomized controlled trial

Serum HBeAg levels and HBe-seroconversion were investigated in patients with chronic HBeAg-positive hepatitis who were randomized to receive either alpha lymphoblastoid interferon (5 megaunits subcutaneously daily for 16 weeks) plus acyclovir (2 g intravenously daily during weeks 1 and 2 and weeks 9 and 10) (n = 49) or no treatment (n = 48). HBeAg levels in serial dilutions of patient serum were assessed quantitatively by radioimmunoassay and compared with the values found for negative control serum. One year after the start of therapy 44 treated patients and 43 control patients were available for follow-up. A complete response (HBe-seroconversion) occurred in 11 treated patients (25%) and six controls (14%) (difference: 11%, 95% CI-5-28%). A partial response (HBeAg less than 50% of initial level) was found significantly more often for treated patients (n = 13, 30%) than for controls (n = 2, 5%) (difference: 25%, 95% CI 10-40%). During acyclovir-interferon combination therapy the decrease in HBeAg level was similar to that achieved during therapy with interferon alone. We conclude that acyclovir does not enhance the effect of interferon on serum HBeAg levels. Since HBeAg levels continue to decline during interferon treatment and rebound thereafter to pretreatment levels, prolongation of therapy may yield a higher response rate.

Mechanisms of terbutaline-induced inhibition of exocrine pancreatic secretion in humans.

Terbutaline, a selective P,-adrenoreceptor agonist, has recently been advocated as a potential agent for treating patients with pancreatic fistulae. In the present study, we attempted to quantify the presumed effects of terbutaline on exocrine pancreatic secretion in humans and to characterize possible mechanisms of action. In six healthy volunteers, the pancreas was stimulated by infusion of graded doses of secretin (15.5-250 ng/kg/h) or by infusion of secretin (15.5 ng/kg/h) plus graded doses of caerulein (3.3-30 ng/ kgh). The experiments were repeated in each subject without and with administration of terbutaline. Pancreatic secretion was assessed by a marker perfusion technique and plasma somatostatin and pancreatic polypeptide (PP) levels by radioimmunoassay. Terbutaline had no significant effect on secretinstimulated pancreatic secretion, but significantly inhibited caerulein-stimulated pancreatic fluid secretion and trypsin output. Plasma somatostatin and PP levels were not affected by terbutaline. The inhibitory effect required the administration of pharmacologically large doses of terbutaline. We conclude that the weak inhibitory effect of terbutaline on exocrine pancreatic secretion is not mediated via somatostatin nor PP and that our data do not support a major role for P-adrenergic mechanism as regulator of pancreatic secretion.

Effect of adding albumin to solutions of cholecystokinin on pancreatic protein output and pancreatic polypeptide release.

In four conscious dogs with chronic gastric and pancreatic Thomas fistulas we studied the effect of 99% pure cholecystokinin-33 (CCK-33) solutions on pancreatic secretion and PP release. CCK-33 was dissolved in 0.154 M NaCl alone or in the same solution containing 1 g per 100 ml dog albumin. The response of pancreatic protein output to increasing doses of CCK-33 (0.5, 1, 2, 4 IDU/kg per h) was significantly (P less than 0.05) higher when CCK was dissolved in NaCl with albumin than in NaCl alone. These results were confirmed by measuring CCK immunoreactivity in samples from tips of infusion lines by a gastrin radioimmunoassay. Release of pancreatic polypeptide (PP) following increasing doses of CCK-33 was also significantly (P less than 0.05) elevated when CCK was dissolved in an albumin-containing solution. There was a significant (P less than 0.02) correlation between plasma concentrations of PP and pancreatic protein output. This study suggests that albumin should be added to CCK-33 solutions to preserve biological activity. The biological effect of CCK-33 may be substantially underestimated if albumin is omitted.