A longitudinal study of the usage of acid reducing medicine using a medicine claims database
Janse van Rensburg, Hendrika Nicolien
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Acid-related disorders are common, chronic conditions that have considerable impact on a patient's quality of life. In a study conducted by Majumdar et al. (2003:2411) the prevalence of chronic acid-related disorders was 2.3%. Acid-related disorders represent a major financial consideration with respect to the costs of drug prescribing (Whitaker, 1998:6). Health care cost increases each year. This leads to an increased interest in economic evaluation of health care and medical technologies (Anell & Svarvar, 2000:175). Health care providers no longer make treatment decisions independent of the consideration of the resultant cost. The treatment provided must not only provide value but the value must be documented to justify spending money. Economic evaluation research has emerged to offer guidance to policy makers, practitioners, health plans and institutions facing difficult treatment and coverage decisions (Ellis era/., 2002:271). The main objectives of this study were to investigate the prescribing patterns and cost of acid reducing medicine with special reference to proton pump inhibitors and histamine-2 receptor antagonists in a section of the private health care sector of South Africa from 2001 to 2006. A longitudinal retrospective drug utilisation study was done on acid reducing medicine items claimed through a national medicine claims database. The five study years were 2001, 2002, 2004, 2005 and 2006. All the study years stretched from 1 January to 31 December. It was determined that acid reducing medicine items prescribed decreased from 2.74% during 2001 to 2.50% during 2006 of all medicine items claimed. The same decreasing trend was observed regarding the cost of acid reducing medicine items. The cost percentage decreased from 4.89% (2001) to 3.72% (2006). However, the average cost per medicine item for the acid reducers increased by 5.35% from 2001 (R230.04 ± 176.29) to 2002 (R243.72 ± 184.18) and then decreased by 15.23% from 2002 to 2004. It again decreased with 15.05% from 2004 (R206.19 ± 179.42) to 2006 (R175.70 ± 172.55). The changes in the average cost of acid reducers were of no practical significance. Proton pump inhibitors represented about half of the acid reducing medicine items prescribed and more than 70% of the total cost of acid reducing medicine items during the study years. The average cost of PPIs revealed a practical significant decrease (d > 0.8) from 2002 (R372.42 ± 156.62) to 2006 (R241.56 ± 177.21). H2RAs contributed between 15.00% and 18.26% of all acid reducing medicine items while contributing to between 9.68% and 16.85% of the total cost of all acid reducers. The active ingredient most often prescribed was lansoprazole during 2001 and 2002, esomeprazole during 2004 and omeprazole during 2005 and 2006. Lanzor® 30mg was the acid reducer with the highest cost from 2001 to 2005, while Pariet® 20mg took the lead in 2006. Zantac® 150mg effervescent tablets were the H2RA, with the highest cost, during the five study years. The percentage innovator items decreased by 4.50% from 2001 to 2002, increased by 1.01% from 2002 to 2004 and decreased again by 31.06% from 2004 to 2006. The slight increase in the percentage innovator medicine items claimed from 2002 to 2004 may be explained by the introduction of Nexiam® (esomeprazole) into the market in 2002. The total number of generic medicine items claimed contributed between 9.62% (n = R1 788 242.25) in 2001 and 30.75% (n = R3 196 163.34) in 2006 of the total cost of acid reducing medicine items. The average cost per day of innovator medicine items was higher than the average cost per day of generic medicine items. This might be explained by a lower average cost for generic medicine items. It was also determined that the prevalence of the two-drug regimens was the highest during the five study years. The Helicobacter pylori (H.pylori) eradication treatments, which included different antibiotics, increased from 2.72% in 2001 to 5.05% in 2006. The PDD for most of the active ingredients of H2RAs and PPIs remained stable during the study years. However, it appears that the PDDs, of the PPIs, active ingredients were more constant than the PDDs, or the H2RAs, active ingredients. The median of the different PPI active ingredients was reasonably more constant than the median of the different H2RA active ingredients. Thus the changes between the PPIs' and H2RAs' active ingredients might be explained by the variation in the median (the number of days the relevant medicine item was claimed for). It is then also recommended that the aspects of generic substitution as well as the usage of H2RAs as prescribed vs. self medication should be further investigated to increase possible cost savings.
- ETD@PUK