Cost-effectiveness of macrogol 4000 compared to lactulose in the treatment of chronic functional constipation in the UK

Objective: To estimate the cost-effectiveness of macrogol 4000 compared to lactulose in the treatment of chronic functional constipation, from the perspective of the National Health Service (NHS) in the UK. Methods: A decision model depicting the management of chronic functional constipation was constructed using clinical outcomes and resource use values derived from patients suffering from chronic functional constipation in The Health Improvement Network (THIN) Database. The model was used to estimate the cost-effectiveness of a general practitioner (GP) prescribing macrogol 4000 relative to lactulose to treat adults >= 18 years of age suffering from chronic functional constipation. Results: Forty-two per cent (95% confidence interval [CI]: 38%; 46%) of macrogol 4000-treated patients are expected to be successfully treated within 3 months after starting treatment, compared to 31% (95% CI: 27%; 37%) of lactulose-treated patients. Patients' health status at 3 months was estimated to be 0.213 (95% CI: 0.200; 0.223) and 0.210 (95% CI: 0.197; 0.220) quality-adjusted life years (QALYs) in the macrogol 4000 and lactulose groups, respectively. The total 3-monthly NHS cost of treating patients with macrogol 4000 or lactulose was estimated to be 115 pound (95% CI: 98; pound 132) pound and 102 pound (95% CI: 86; pound 119) pound, respectively. Hence, the cost per QALY gained with macrogol 4000 was estimated to be 4333 pound. Conclusion: Within the limitations of the model, treatment with macrogol 4000 relative to lactulose is expected to increase the probability of being successfully treated by 35% at 3 months (p<0.0001), although this yields only a 1% improvement in health gain. Nevertheless, macrogol 4000 affords a cost-effective addition to the range of laxatives available for this potentially resource-intensive condition, since it is clinically more effective than lactulose and the cost-effective strategy from the perspective of the NHS.