Model predicts millions of dollars can be saved just by avoiding 3 high-cost, low-reward drugs.
Research published in Canadian Family Physician addressed improvements needed to help doctors make cost-effective decisions when prescribing medication. According to the report, intraclass medications often have equivalent levels of efficacy, toxicity, and convenience, creating an opportunity for doctors to base their product choice on comparative costs. Yet, prescribing doctors have very little training or resources to inform cost-based decisions.
Authors offered rational prescribing as a possible solution. Conservatively, they estimated that rational prescribing could save $521 million annually, and possibly as much as $1 billion. Although Canada has universal healthcare, like the United States they lack universal prescription coverage.
A rational prescribing model takes 4 principles into consideration when selecting an appropriate medication: efficacy, toxicity, cost, and convenience.
Obviously, efficacy is the top priority, without which no other factor is relevant. Under this model, efficacy outcomes, in order of importance, are (1) mortality, (2) morbidity, (3) surrogate markers (assessed for clinical relevance), and (4) symptomatic relief. These outcomes should be considered in the context of absolute effect size and quality of evidence.
Risks of toxicity, in order of importance, are (1) mortality, (2) morbidity, and (3) bothersome symptoms. The parameter of time is an important consideration here, since adverse events and key safety data are best derived from phase IV surveillance studies and not just preclinical trials, the authors said.
Provided that the first 2 principles are equivalent for the same therapeutic indication, drugs are compared on the basis of cost and convenience. Both of these principles have a potential impact on medication adherence. Differences in convenience may include (1) route, (2) frequency, and (3) timing of doses; also, (4) monitoring requirements, (5) potential for drug interactions, and (6) setting of administration.
This study began by looking at the 10 classes of prescription drugs with the highest national spending, as determined by the Canadian Institute for Health Information (CIHI). Researchers conducted a literature review to compare clinical outcomes and therapeutic indications within each class.
Antineovascularization agents were eliminated from the study because there was only 1 medication in the class. Several classes were eliminated from the study because of differing intraclass prescribing indications: tumor necrosis factor-a inhibitors; adrenergics and other agents for obstructive airway disease; natural opium alkaloids; diazepines, oxazepines, thiazepines, and oxepines; and other antidepressants.
This left 4 classes remaining: statins; proton pump inhibitors (PPIs); angiotensin-converting enzyme inhibitors (ACEIs); and selective serotonin reuptake inhibitors (SSRIs).
For these 4 drug classes, annual prescribing data were drawn from the 2013 National Prescription Drug Utilization Information Systems Database (NPDUIS). In each class, researchers calculated a conservative nonswitching constant: 94% for statins, 80% for PPIs, 92% for ACEIs, and 60% for SSRIs. Then, estimated market shares were projected under a rational prescribing model and compared with current pharmaceutical market shares.
Spending through public drug programs was based on actual data, and researchers extrapolated total national spending (including private insurance) by applying the appropriate public-to-private ratio from Rx Atlas, a publication from the UBC Centre for Health Services and Policy Research.
Authors determined that statins, PPIs, ACEIs, and SSRIs have class equivalence for efficacy, toxicity, and convenience. Current spending on these classes is $856 million through public drug programs and an estimated $1.97 billion annually in Canada. These are conservative estimates, since the most expensive patent-protected drugs may not be covered or represented in claims data.
Conservatively, rational prescribing could save $222 million for public drug programs and a total of $521 million per year.
Meanwhile, $403 million, or 78%, of these annual savings would be the direct result of lower prescription volumes for just 3 drugs: escitalopram, esomeprazole, and perindopril, the authors said.
Authors noted that actual spending on these 3 drugs could be twice as high as their estimate, or $850 million, based on data from the 2013 Rx Atlas. Accounting for spending not represented in the study data, the authors said that simply deprescribing these 3 most expensive drugs could lead to nearly $1 billion in savings annually.
This study found that the least expensive, therapeutically equivalent drugs in each class were rosuvastatin, rabeprazole, ramipril, and citalopram.