Economic Evaluation in Gastrointestinal Disease

Abstract

Safety and efficacy are not the only parameters of interest in the choice of medical technology—costs are playing an increasingly important role. There is growing interest in ‘value for money', which can be assessed economically by comparing the costs and consequences of alternative courses of action. A number of different economic evaluation methods may be used: cost-minimization (only costs examined with no consideration given to consequences); cost-effectiveness (in which a unidimensional clinical outcome is assessed, for example, life-years gained); cost-utility (multidimensional outcomes measured, for example quantity and quality of life); and cost-benefit (where outcome is considered in monetary terms). Ulcer disease offers several examples of how economic evaluation can be used to address issues related to efficiency and value for money in healthcare. In a study of reflux oesophagitis, omeprazole was shown to be more cost-effective than ranitidine in a 12-week treatment study. With omeprazole the costs were lower and the effectiveness better than with the H₂-receptor antagonist. In a later study the cost-effectiveness of omeprazole and ranitidine are compared for both intermittent and maintenance treatment in reflux oesophagitis. Using a Markov chain approach, Swedish cost data and studying a time period of 12 months, it is found that omeprazole is both more effective in providing healthy days and less costly than ranitidine for both treatment strategies. The comparison between intermittent treatment and maintenance treatment with omeprazole shows that the latter is more effective but also more costly. It is concluded that the relative cost-effectiveness of omeprazole maintenance treatment increases with the risk of relapse when off treatment, the severity of symptoms following relapse, and the value of healthy days, i.e. days free from reflux oesophagitis. A model analysis comparing Helicobacter pylori eradication with conventional treatments in patients with duodenal ulcer disease has shown H. pylori eradication to be cost-effective when compared with either episodic therapy using omeprazole or maintenance therapy with ranitidine. The study used a Markov chain approach, and included the cost of treatment, in Swedish crowns, in a Swedish primary care setting over a period of 5 years. In the analysis, patients receiving conventional therapy were initially healed with omeprazole, 20–40 mg once daily. Following healing, patients were either treated with further courses of omeprazole upon relapse or were given maintenance treatment with ranitidine, 150 mg once daily. The patients who were assigned to the H. pylori eradication therapy group were initially given an H. pylori test. Those patients who proved positive for the bacterium received omeprazole, 20 mg twice daily, plus amoxicillin, 2000 mg daily in divided doses, for 2 weeks, followed by omeprazole, 20 mg once daily, for a further 2 weeks to ensure healing. Patients who were H. pylori-negative were assigned to receive either episodic or maintenance therapy as described above. The model assumption applied in the H. pylori eradication group was that, following successful healing and H. pylori eradication, virtually all patients were cured and experienced no relapse during the following 5 years. By contrast, almost all the patients assigned to episodic therapy relapsed and, during maintenance therapy with H₂-receptor antagonists, most patients experienced at least one relapse. Although H. pylori eradication resulted in initial higher costs than the alternative strategies, it reduced the risk of recurrence and for most patients there were no future costs. The investment therefore paid off within a relatively short period of time. Even when unfavourable assumptions were made, such as an H. pylori eradication rate of only 50%, the H. pylori eradication strategy had a pay-off period of less than 1.3 years compared with maintenance treatment, and 3 years compared with episodic treatment. Based on an American multicentre study, an economic evaluation of prophylactic misoprostol was undertaken in Sweden. The study included 420 patients with osteoarthritis and nonsteroidal antinflammatory drug (NSAID)-associated abdominal pain, but no gastric ulcer at inclusion. The frequency of ulcer development with and without prophylactic misoprostol was assessed at 21.7% and 5.6%, respectively, for a 3-month period. All costs for drugs, ambulatory care, hospital care, loss of production, as well as factors such as dosage and compliance, were transferred to Swedish conditions. It was concluded that in patients with osteoarthritis and NSAID-induced abdominal pain prophylaxis with misoprostol is cost-effective in Sweden, which is similar to what is found in other countries. A prerequisite for this result is a frequency of ulcer development of 15%. A patient compliance to prophylactic treatment of more than 60% is also presupposed (79% was observed in the above study). Owing to the high age of the osteoarthritis patient population, cost-effectiveness is influenced to only a minor extent by whether indirect costs are included in the calculation. A review of studies about screening for colon cancer concludes the paper.

Key Words:

• Colon cancer
• cost-effectiveness
• misoprostol
• omeprazole
• pharmaco economics
• reflux oesophagitis
• ulcer disease