Analysis from Medicare claims data from Precision’s Research Economist Joanna MacEwan, PhD at the American Diabetes Association 2015 Scientific Sessions.

By Miriam E. Tucker

BOSTON — Among US Medicare beneficiaries with type 2 diabetes, out-of-pocket expenses diminish adherence to medication and may end up increasing overall healthcare costs in the long run, a new study finds.

The results, from an analysis of Medicare claims data for 2006–2009, were presented by research economist Joanna P MacEwan, PhD, of Precision Health Economics, at the American Diabetes Association (ADA) 2015 Scientific Sessions.

The findings indicate that what Medicare may believe it is saving by having patients pay high copays could end up costing it more for other medical expenses. “While increased cost-sharing may lower pharmacy costs, it may also decrease adherence and raise total expenditures,” Dr MacEwan said in her introduction. She told Medscape Medical News, “Elderly patients are sensitive to treatment costs, and their adherence may decline if the addition of new drugs or rising cost of current therapies increases their out-of-pocket spending, and poor adherence is associated with higher medical costs. “Clinicians should consider patients’ costs as a factor in determining patient-adherence behavior and reinforce good adherence because, although adherent patients may spend more out of pocket on medications, this cost will likely be more than offset by savings in medical expenditures.”

Asked to comment on the study, session moderator Erinn T Rhodes, MD, director, endocrinology healthcare research and quality at Boston Children’s Hospital, Massachusetts, said, “The question would be, ‘Could this have implications for how clinicians talk to their patients?’…More work needs to be done, but I think it’s worth thinking about.”

Medical Expenditures Account for the Vast Majority of Costs in Diabetes

Dr. MacEwan’s presentation was titled “Penny-wise, Pound-foolish: Association Between Medication Adherence, Out-of-Pocket Expenses, and Healthcare Costs in Medicare Patients with Type 2 Diabetes.” The study involved claims data from a random sample of 12,197 Medicare beneficiaries with a new or existing diagnosis of type 2 diabetes. The patients in the upper decile of total spending were more likely to also have heart failure, complicated hypertension, depression, and some degree of renal impairment. They were also more likely to use insulin therapy. Age and gender balance did not differ significantly across deciles of total cost. Adherence was measured as proportion of days covered over the first 12-month window of observation.

Although the most adherent (tenth decile) of patients had somewhat higher total pharmacy costs compared with the least adherent (first decile) patients ($4839 vs $3046), these patients had much lower total expenditures ($12,531 vs $24,468) and medical expenditures ($7692 vs $21,421), which include costs for doctor visits, hospitalization, and surgery, among other things.

Total out-of-pocket spending for patients in the lowest decile of adherence was $2116 vs $1344 for patients in the highest decile of adherence. Again, out-of-pocket pharmacy spending was moderately higher for patients in the highest vs lowest deciles of adherence, $737 vs $441, respectively. However, most of the overall difference was attributable to out-of-pocket medical spending between patients in the lowest and highest deciles of adherence, $1675 vs $607, respectively.

The results of a sensitivity analysis using a different measure of adherence (medication/possession ratio)

corroborated the main analysis, Dr. MacEwan reported. “Medical expenditures account for the vast majority of expenditures in type 2 diabetes patients…and reduced medication adherence in this group could further exacerbate this skewed medical spending,” she told Medscape Medical News.

In response to a question from Medscape Medical News about the specific drivers of those medical costs, Dr. MacEwan responded, “We have the data and could look at the types of services patients in the higher deciles of spending received, but we did not in this study. Given the higher prevalence of comorbidities like heart failure and complicated hypertension, it is likely that these costs are in part explained by more frequent and/or longer inpatient hospital stays, but we would have to do additional analysis to be sure.”

As a next step, she said, “we are designing a study to identify the effect of insurance/benefit-plan generosity on medication adherence, diabetes complication rates, and spending in the type 2 diabetes population.”

The study was funded by AstraZeneca. Dr MacEwan is an employee of Precision Health Economics, which provides consulting and other research support to pharmaceutical, device, governmental, and nongovernmental organizations; she has consulted for AstraZeneca. Disclosures for the coauthors are listed in the abstract. Dr. Rhodes receives research funding from Merck, and her spouse has stock in Pfizer.