Impact of the COVID-19 pandemic on prescription refills for immune-mediated inflammatory disorders: a time series analysis (January 2019 to January 2021) using the English Prescribing Dataset

OBJECTIVE: To investigate monthly prescription refills for common immunosuppressive/immunomodulatory therapy (sulfasalazine, hydroxychloroquine, azathioprine, methotrexate, leflunomide) prescriptions in England during the complete first wave of the COVID-19 pandemic. Secondary analysis examined unit cost analysis and regional use. DESIGN AND SETTING: A national cohort of community-based, primary care patients who anonymously contribute data to the English Prescribing Dataset, dispensed in the community in England, were included. Descriptive statistics and interrupted time series analysis over 25 months (14 months before, 11 months after first lockdown) were evaluated (January 2019 to January 2021, with March 2020 as the cut-off point). OUTCOME MEASURES: Prescription reimbursement variance in period before the pandemic as compared with after the first lockdown. RESULTS: Fluctuation in monthly medicines use is noted in March 2020: a jump is observed for hydroxychloroquine (Mann-Whitney, SE 14.652, standardised test statistic 1.911, p value=0.059) over the study period. After the first lockdown, medicines use fluctuated, with wide confidence intervals. Unit-cost prices changed substantially: sulfasalazine 33% increase, hydroxychloroquine 98% increase, azathioprine 41% increase, methotrexate 41% increase, leflunomide 20% decrease. London showed the least quantity variance, suggesting more homogeneous prescribing and patient access compared with Midlands and East of England, suggesting that some patients may have received medication over/under requirement, representing potential resource misallocation and a proxy for adherence rates. Changepoint detection revealed four out of the five medicines' use patterns changed with a strong signal only for sulfasalazine in March/April 2020. CONCLUSIONS: Findings potentially present lower rates of adherence because of the pandemic, suggesting barriers to care access. Unit price increases are likely to have severe budget impacts in the UK and potentially globally. Timely prescription refills for patients taking immunosuppressive/immunomodulatory therapies are recommended. Healthcare professionals should identify patients on these medicines and assess their prescription-day coverage, with planned actions to flag and follow-up adherence concerns in patients.