Cost‐effectiveness of alginic acid in combination with proton pump inhibitor for the treatment of gastroesophageal reflux disease in systemic sclerosis patients

Systemic sclerosis (SSc) patients often become refractory to proton pump inhibitors (PPI)-a standard treatment for gastroesophageal reflux disease (GERD)-and intolerant to PPI in combination with domperidone. PPI with alginic acid is an alternative treatment option, but alginic acid is costly.We compared the costs and effectiveness of alginic acid plus PPI versus standard treatments (PPI with/without antacids as needed and lifestyle modifications) for GERD in SSc patients unsuitable for, or intolerant to, domperidone.An economic evaluation using the Markov model was conducted among SSc patients aged between 40 and 65 years with GERD, having a partial or non-response to 4 weeks of standard-dose omeprazole (40 mg/day) and being unsuitable for or intolerant to domperidone. Using a societal perspective, we computed the incremental cost-effectiveness ratios (ICERs) in terms of Thai baht (THB) per quality-adjusted life-year (QALY) between a combination of alginic acid plus PPI and standard treatment for GERD. The lifetime time horizon was used.The ICER for alginic acid plus PPI versus standard treatments was 377 101 THB/QALY. According to the one-way sensitivity analysis, the cost of alginic acid was the most impactful parameter. If the market prices of alginic acid plus PPI were reduced by 61%, this treatment option would become cost-effective at the willingness-to-pay threshold of 160 000 THB/QALY (34.68 THB/USD data on 25 May 2023). Furthermore, if alginic acid were included in the public health insurance program, the national budget would be increased by 66 313 THB per patient, resulting in an overall budget increase of 5 106 101 to 8 885 942 THB compared with the standard treatment.Alginic acid plus PPI does not represent good value for money compared with the standard treatment among such SSc patients in Thailand unless its price is reduced significantly.