Economic evaluation of single-pill combination of indapamide and amlodipine in the treatment of arterial hypertension in the Polish setting

Background: Arterial hypertension is a common disorder that affects around 9 million adults in Poland. Single-pill combinations (SPCs) for the treatment of arterial hypertension have significant advantages over the free combinations, resulting in lower risk of cardiovascular events and lower consumption of medical resources. The current ESC/ESH 2013 guidelines for the first time recommend treatment with a combination of thiazide-like diuretic with calcium channel blocker. Currently, no such combination is reimbursed from public funds in Poland. Aim: To assess the economic value of treatment with SPC of indapamide and amlodipine (Tertens-AM (R)) for hypertensive patients compared with free combination therapy (FC), in the Polish setting. Methods: As there are currently no published data directly estimating the additional effect of using indapamide + amlodipine SPC vs. FC, two extreme approaches are presented: with difference in effectiveness due to improved adherence to the treatment estimated from published studies on other molecules used in hypertension such as SPCs and FCs - the base-case approach (1); and assuming no difference of effectiveness or adherence between SPC and FC of indapamide and amlodipine - the conservative approach (2). Modelling was carried out based on the Markov process in lifetime horizon. In the base-case approach, with the difference in effectiveness between SPC and FC, it was assumed that the differences in compliance translate into the differences in systolic blood pressure. Patients' characteristics were correlated with the risk of events associated with cardiovascular disease, based on the prediction algorithms from the Framingham Heart Study. Costs were considered from a National Health Fund (NHF) perspective and NHF and patient's perspective, and therefore direct medical costs were only included. Results: The treatment with SPC of indapamide and amlodipine in place of FC resulted in 7.6 additional days of life in full health and longer overall patient survival by 2.9 days. The replacement of FC with SPC would result in national savings from both NHF perspective and NHF and patient's perspective, irrespective of the assumption of the difference in adherence between SPC and FC. The savings would amount to 1.602-3.954 million PLN and 16.498-19.186 million PLN from NHF perspective and NHF and patient's perspective, respectively. Conclusions: The treatment with SPC of indapamide and amlodipine for hypertensive patients was found to be dominant over FC or at least less expensive than treatment with FC when the difference in effectiveness was neglected. The replacement of FC with SPC would result in savings from both NHF perspective and NHF and patient's perspective.