Proton pump inhibitor use with aspirin secondary prevention 'cost-effective'

19 August 2008

MedWire News: Proton pump inhibitor (PPI) cotherapy in conjunction with low-dose aspirin for secondary cardiovascular disease prevention is cost-effective in average-risk patients at over-the counter (OTC) cost, but only in high risk patients at prescription cost, Markov model findings indicate.

Sameer Saini (University of Michigan, Ann Arbor, USA) and co-authors of the study explain that the risk for upper gastrointestinal bleeding (UGIB) in patients taking aspirin for secondary prevention can be minimized with PPI cotherapy.

To look at whether long-term PPI cotherapy is cost-effective from the perspective of a long-term medical insurance payer such as Medicare, the researchers developed a Markov model to compare the costs of secondary prevention with low-dose aspirin and low-dose aspirin plus PPI in patients with coronary heart disease who were aged at least 50 years.

Assuming patients had a starting age of 65 years, were at average risk for UGIB (had no established risk factors other than age), and that PPI therapy reduces the risk for UGIB by 66% (based on randomized data in high-risk Asian patients), the model indicated that using a PPI with aspirin rather than aspirin alone would reduce the lifetime risk for UGIB events from 9.5% to 3.1% and that for UGIB-related death from 1.4% to 0.4%.

At OTC cost, the authors say that the PPI plus aspirin combination in this scenario was cost effective, at a cost-effectiveness ratio per life-year gained of $40,090.

Patient age, the effectiveness of PPI for reducing UGIB, and the cost of PPI all affected how cost-effective the combination would be, with younger age, lower efficacy, and higher costs making the ratio less favorable.

Cost-effectiveness ratios per life-year gained varied from $35,315 up to $94,578 across starting ages ranging from 50 to 80 years.

And increasing the PPI cost to prescription prices made the strategy cost-ineffective in all but the highest risk patients. The cost-effectiveness ratio per life-year gained for patients at high risk (4-fold higher than average) for UGIB was $100,000 in 50-year-olds, $51,000 in 65-year-olds, and $25,000 in 80-year-olds.

In an accompanying editorial, Michael Pignone (University of North Carolina, Chapel Hill, USA) pointed out that achieving the cost-effectiveness ratios under $50,000 would currently require use of the generic omeprazole magnesium, which has not been evaluated for preventive efficacy.

Also, he said: "We need greater confidence about the risk for adverse effects of PPI from fractures, pneumonia, or other unrecognized conditions."

Arch Intern Med 2008; 168: 1684-1690