RESUMEN
BackgroundAlthough studies have quantified adherence to medications among patients with rheumatic diseases (RD) during the COVID-19, lack of direct pre-pandemic comparison precludes understanding of impact of the pandemic.ObjectivesOur objective was to evaluate the effect of the COVID-19 pandemic on adherence to disease modifying drugs (DMARDs) including conventional synthetic (csDMARDs) and targeted synthetic (tsDMARDs).MethodsWe linked population-based health data on all physician visits, hospital admissions, and all dispensed medications, regardless of payer in British Columbia from 01/01/1996 to 3/31/2021. We identified prescriptions for csDMARDs (including methotrexate, hydroxychloroquine) and tsDMARDs, namely anti-TNFs (including infliximab, etanercept, adalimumab) and rituximab using drug identification numbers among indicated individuals with RD. We defined March 11, 2020, as the ‘index date' which corresponded to the date that mitigation measures for the COVID-19 pandemic were first introduced. We assessed adherence as proportion days covered (PDC), calculated monthly in the 12 months before and 12 months after the index date. We used interrupted time-series models, namely segmented regression to estimate changes and trends in adherence before and after the index date.ResultsOur analysis showed that the mean PDCs for all included DMARDs stayed relatively steady in the 12 months before and after mitigation measures were introduced (see Table 1). Adherence was highest among anti-TNFs, methotrexate, and azathioprine. Anti-TNFs were on a downward trajectory 12 months prior to the index date. Interrupted time-series modeling demonstrated statistically significant differences in the trends in PDCs post- vs. pre-mitigation measures for all anti-TNFS (slope [∂]: 1.38, standard error [SE]: 0.23), infliximab (∂: 1.35, SE: 0.23), adalimumab (∂: 0.82, SE: 0.25), and etanercept (∂: 1.07, SE: 0.25) (see Figure 1a). Conversely, the csDMARDs were on a flatter trajectory, and methotrexate (∂: -0.53, SE: 0.16), leflunomide (∂: 0.43, SE: 0.08), mycophenolate (∂: -1.26, SE: 0.48), cyclophosphamide (∂: 0.29, SE: 0.05), minocycline (∂: 0.04, SE: 0.02), chloroquine (∂: 0.02, SE: 0.00) showed statistically significant changes in estimated PDC trajectory after mitigation measures were introduced (see Figure 1b).ConclusionThis population-based study demonstrates that messaging and pandemic mitigation measures did not affect adherence to DMARDs.Table 1.Mean PDC 1 year before and after mitigation measures for the COVID-19 pandemic were introduced.MedicationMean PDC (%) 12 months before index dateMean PDC (%) 12 months after index datecsDMARDsmethotrexate28.926.8azathioprine21.819.5sulfasalazine16.214.9leflunomide14.313.0cyclosporine13.711.5hydroxychloroquine10.59.6mycophenolate4.52.9antimalarials4.43.9penicillamine3.53.4cyclophosphamide1.50.7chlorambucil1.20.4minocycline1.10.9gold0.50.2chloroquine0.10.0tsDMARDsanti-TNFs52.149.2infliximab41.838.3adalimumab40.336.8etanercept31.828.9rituximab3.42.9REFERENCES:NIL.Acknowledgements:NIL.Disclosure of InterestsNone Declared.