AUTHOR=Tachkov Konstantin , Vassilev Anton , Kostova Stanislava 

TITLE=Modeling the Pharmacotherapy Cost and Outcomes of Primary Open-Angle Glaucoma With Dry Eye

JOURNAL=Frontiers in Public Health

VOLUME=Volume 7 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2019.00363

DOI=10.3389/fpubh.2019.00363

ISSN=2296-2565

ABSTRACT=We aimed to analyze and model the cost and results of current outpatient pharmacotherapy practice in patients with primary open angle glaucoma and concomitant with dry eye disease (POAG+DE). The point of view is that of the health care system and patients and time horizon was one year.
Data was collected through a prospective, observational, real-life study of therapy practice from patients admitted to the specialized ophthalmology clinic at the University hospital “Alexandrovska” in Sofia. Pharmacotherapy was recorded and analyzed by therapeutic group and INN. Probability of being prescribed preservative free or non-free formulations was calculated as well as cost of yearly therapy, reimbursed cost, and patient co-payment. A decision tree exploring cost-effectiveness of preservative free and preservative non-free formulations was built. Outcomes were recorded through three tests measuring tear film stability - TMS, NIBUT Ave and ST. TMS values below 3, ST above 10mm and NIBUT Ave above 14 sec were considered as an indicator for a good disease control. 
140 eyes were diagnosed with POAG  out of which 64 were with concomitant dry-eye disease and included in the analysis. 34 were prescribed monotherapy – 14 on preservative free formulations and 20 on non-free. 30 eyes received combination therapy – 6 on preservative-free and 24 on non-free. Monotherapy products consisted of Prostaglandin Analogues (PG – 73.5%); followed by beta blockers (BB - 26.5%). No carbonic anhydrase inhibitors (Ca AA) and alpha-2 adrenergic agonists (alfa 2 AA) were prescribed as monotherapy. Majority of patients showed poor disease control in all three measures. Incremental cost-effectiveness ratio (ICER) was 744BGN for TMS and 131 BGN for NUBIT for each successfully controlled eye - far below the 3 times GDP per capita. For ST the ICER is negative, benefiting non-free formulations.
Therapy of POAG+DED with preservatives free formulations is cost-effective according to the WHO threshold of 3 times GDP. Median costs between the two treatment modalities were similar. Current practice shows that patients experience a higher burden in terms of co-payment.