AAN 2011: Cost/Benefit Ratio Favors Transdermal Rivastigmine in Alzheimer's Disease

For patients with Alzheimer's disease (AD), transdermal rivastigmine provides an equal or larger number of quality-adjusted life-years at a lower cost than either galantamine or donepezil, according to a study presented at the 63rd Annual Meeting of the American Academy of Neurology.

The cost per quality-adjusted life-year (QALY) gained was 48,479 Mexican pesos for rivastigmine, 54,926 pesos for galantamine, and 55,526 pesos for donepezil. Converted to US dollars, the respective figures were approximately $4100, $4677, and $4729.

“Alzheimer's disease is a significant public health problem in Mexico,” said lead study author Samaria Cruz, of Novartis Pharmaceuticals in Mexico City. Alzheimer's disease prevalence is 5% in the elderly population, she noted, and costs for care are high for the Mexican Institute of Social Security, which provides health care reimbursement for approximately half of all AD patients in the country. All three cholinesterase inhibitors examined in this study are in the national formulary, and are recommended for symptomatic treatment of Alzheimer's disease by the Institute's guidelines.

The measurement of QALYs has become a standard tool in health outcomes research to compare the utility of different treatments. Quality of life is determined by comparing and ranking different health states, through a series of questions designed to assess their perceived value to the respondent.

To determine QALYs in their study, the authors used data from previous large studies of patients with Alzheimer's disease, in which patients and caregivers ranked the relative value of different levels of cognition (mild, moderate, or severe dementia) or death. These rankings were then used to analyze health outcomes in over 1200 patient records in the Mexican national database over a 10-year follow-up period. Data on cognitive levels were combined with adverse events and hospitalizations associated with each of the three cholinesterase inhibitors, to arrive at a measure of “utility” (efficacy plus adverse events) for each treatment.

Utility was 3.56 for rivastigmine transdermal system, 3.44 for galantamine, and 3.55 for donepezil. These were then weighed against 10-year cost for each treatment. The total 10-year cost for each agent was 172,683 pesos ($14,700) for rivastigmine TS, 189,007 pesos ($16,100) for galantamine, and 197,025 pesos ($16,780) for donepezil.

“From an institutional perspective, rivastigmine transdermal system represents the option with the lowest cost per QALY gained,” Cruz said, “making it the cost-saving alternative for the treatment of patients with Alzheimer's disease.” While all three drugs are in the formulary, she noted, physicians are expected to begin treatment with the least expensive effective option.

The study was funded by Novartis Pharmaceuticals.