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PubMed · 9683093

Sample size calculation in economic evaluations.

Abstract

A simulation method is presented for sample size calculation in economic evaluations. As input the method requires: the expected difference and variance of costs and effects, their correlation, the significance level (alpha) and the power of the testing method and the maximum acceptable ratio of incremental effectiveness to incremental costs. The method is illustrated with data from two trials. The first compares primary coronary angioplasty with streptokinase in the treatment of acute myocardial infarction, in the second trial, lansoprazole is compared with omeprazole in the treatment of reflux oesophagitis. These case studies show how the various parameters influence the sample size. Given the large number of parameters that have to be specified in advance, the lack of knowledge about costs and their standard deviation, and the difficulty of specifying the maximum acceptable ratio of incremental effectiveness to incremental costs, the conclusion of the study is that from a technical point of view it is possible to perform a sample size calculation for an economic evaluation, but one should wonder how useful it is.

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BibTeXRIS

M J Al, B A van Hout, B C Michel, F F Rutten. 1998. Sample size calculation in economic evaluations.. https://doi.org/10.1002/(sici)1099-1050(199806)7%3A4%3C327%3A%3Aaid-hec342%3E3.0.co%3B2-u

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Lansoprazole compared with ranitidine for the treatment of nonerosive gastroesophageal reflux disease.

BACKGROUND: Traditionally, proton pump inhibitors are used primarily for patients with esophagitis. However, patients with nonerosive reflux disease may also benefit from these powerful medications. OBJECTIVE: To compare the safety and symptom relief efficacy of lansoprazole with ranitidine therapy and with placebo. METHODS: In 2 randomized, double-blind, multicenter trials of 901 patients with symptomatic reflux disease, which was confirmed by endoscopy to be nonerosive, received lansoprazole, 15 or 30 mg once daily; ranitidine, 150 mg twice daily; or placebo for 8 weeks. RESULTS: Analysis of daily diary data during the first 4 weeks and for the entire 8 weeks of treatment revealed that patients who were treated with either dosage of lansoprazole reported significantly (P<.05) lower percentages of days and nights with heartburn, less pain severity of both day and night heartburn, fewer days of antacid use, and smaller amounts of antacid use compared with patients who were treated with ranitidine or placebo. The incidence of possible or probable treatment-related adverse reactions was comparable among the treatment groups; abdominal pain and diarrhea were the most commonly reported adverse events. No statistically significant differences were noted between treatment groups in laboratory analyses. CONCLUSION: Lansoprazole therapy is more effective than standard dosages of ranitidine or placebo in relieving symptoms in patients with endoscopically confirmed non-erosive reflux esophagitis.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Superiority of lansoprazole vs ranitidine in healing nonsteroidal anti-inflammatory drug-associated gastric ulcers: results of a double-blind, randomized, multicenter study. NSAID-Associated Gastric Ulcer Study Group.

BACKGROUND: The usefulness of nonsteroidal anti-inflammatory drugs (NSAIDs) is limited by adverse gastrointestinal tract events. OBJECTIVE: To identify the optimal antisecretory therapy for healing of gastric ulcer in patients using NSAIDs and the impact of concurrent Helicobacter pylori infection on ulcer healing. DESIGN: Prospective, double-blind, multicenter, parallel-group study. SETTING: Gastroenterology practices in ambulatory and referral center settings. PATIENTS: Three hundred fifty-three patients with an active, nonmalignant gastric ulcer at least 5 mm in diameter confirmed by endoscopy and biopsy and who continued to receive stable doses of NSAIDs. INTERVENTION: Patients were randomized to receive ranitidine hydrochloride, 150 mg twice daily, or lansoprazole, 15 mg or 30 mg once daily, for 8 weeks. MEASUREMENTS: Healing was assessed by endoscopy at 4 and 8 weeks in an intent-to-treat population. Helicobacter pylori status was assessed by histological examination. RESULTS: After 8 weeks of treatment, healing was observed in 61 (53%) of 115, 81 (69%) of 118, and 85 (73%) of 117 patients receiving ranitidine lansoprazole, 15 mg, and lansoprazole, 30 mg, respectively (P<.05 for ranitidine vs both lansoprazole doses; 95% confidence interval, 3.2-28.0 for ranitidine vs lansoprazole, 15 mg, and 7.4-31.8 for ranitidine vs lansoprazole, 30 mg). The gastric ulcer healing rates were similar between H pylori-infected and -noninfected patients, with a statistically significant increase with the use of lansoprazole vs ranitidine. CONCLUSIONS: In patients who require continuous treatment with NSAIDs, lansoprazole is superior to ranitidine for healing of NSAID-associated gastric ulcers. Healing is not delayed by the presence of H pylori infection.

2-Pyridinylmethylsulfinylbenzimidazoles↗