How Comorbidities Affect Costs and Costs Impact Nonadherence in RA

For patients with rheumatoid arthritis (RA), cost can play a role in patient adherence to medication, but the presence of comorbidities does not impact cost of care for patients, according to 2 abstracts presented at the Virtual 2020 International Society for Pharmacoeconomics and Outcomes Research meeting.

In one study,¹ researchers used a pooled cross-sectional analysis of 2009-2013 Medicare Current Beneficiary Survey data to assess the association between drug coverage type and out-of-pocket (OOP) medication cost with cost-related nonadherence (CRN) for patients with RA in the Medicare population.

Drug coverage type included in the analysis could be no coverage, standalone Medicare prescription drug plan, Medicare Advantage Prescription Drug (MAPD) plan, prescription drug plan plus Medicaid, MAPD plus Medicaid, TRICARE, and private plans. There were 4 questions that identified CRN with either a yes or no:

1. Taking smaller doses
2. Skipping doses to make the medication last longer
3. Delaying getting a prescription filled
4. Deciding not to fill a prescription because of cost

In 1843 person-years, 14.6% had CRN. Patients with an OOP of 5% or greater of income were 2.3 times more likely to have CRN than patients with less than 1% of income.

“Patients with MADP plus Medicaid (HR, 0.18; 95% CI, 0.05-0.71; P = .01), TRICARE (HR, 0.12; 95% CI, 0.02-0.76; P = .02), or private plans (HR, 0.43; 95% CI, 0.26-0.73; P < .01) were less likely to report CRN than those without drug coverage,” the authors wrote.

In the second study,² researchers evaluated 2140 patients with RA to understand their RA-related outpatient treatment costs. All the patients included were being treated with biologic disease-modifying antirheumatic drugs between April 2016 and March 2018. They were followed for 12 months.

The majority (82%) had at least 1 comorbidity. Patients with comorbidities were more likely to be older, white, female, and Medicare insured compared with patients without comorbidities. Before accounting for demographics, patients with comorbidities had higher total RA costs ($56,405 vs $49,298), but after accounting for differences in demographics using generalized linear models, the difference in costs shrunk ($52,209 vs $48,484), and after using propensity score matching (350 patients per group matched without replacement by age, race, payer, and gender), the difference in costs disappeared ($47,697 vs $47,612).

References

1. Zheng D, Thomas J. Prescription drug coverage type, out-of-pocket spending, and cost-related nonadherence among Medicare beneficiaries with rheumatoid arthritis. Presented at: ISPOR 2020; May 18-20, 2020; Abstract PMS81. https://www.ispor.org/heor-resources/presentations-database/presentation/intl2020-3182/102115

2. Edgerton C, Radtchenko J, Holers VM. Outpatient costs in rheumatoid arthritis (RA) patients with vs without comorbidities. Presented at: ISPOR 2020; May 18-20, 2020; Abstract PMS4. https://www.ispor.org/heor-resources/presentations-database/presentation/intl2020-3182/99754