Although the authors say their findings shed light on possible disruptions to insulin supply during COVID-19, they note they could not adjust for those with diabetes who died.
Prescribing patterns for insulin went through peaks and valleys in the weeks before and after the United States shut down in early 2020 for the COVID-19 pandemic, suggesting that at least some of the 7 million people who use the hormone to treat diabetes may have unable to obtain it.
Swings in prescription counts for insulin were reported last week in a research letter in JAMA Network Open, with the insights gleaned from IQVIA claims data.
The analysis, led by Ismaeel Yunusa, PharmD, PhD, Department of Clinical Pharmacy and Outcomes Sciences, University of South Carolina College of Pharmacy, found signs that some patients stockpiled insulin in the weeks before the national state of emergency was declared March 16, 2020, marking the official start of the pandemic in the United States. This was followed by a brief, steep drop in insulin prescribing, and then a new, lower baseline of prescriptions for adults. New prescriptions also fell.
Insulin is used to treat both type 1 (T1D) and type 2 diabetes (T2D). Patients with T1D must rely on insulin for survival, while those with more severe T2D may use insulin to maintain glycemic control. However, patients with T2D can be treated with a variety of other therapies, including both oral and injectable drugs.
A major limitation of the study is the fact that researchers could not adjust for mortality based on the available data. People with diabetes were known to be at higher risk of serious illness and death from COVID-19; in July 2021, the American Diabetes Association reported that 40% of those who died from COVID-19 had diabetes. So, some of the drop off in prescribing could be due to patient deaths.
After an initial drop, the baseline for pediatric insulin prescriptions returned to pre-pandemic levels, the authors found. They speculated this is due to the fact that most pediatric patients use insulin to treat T1D. Overall, new prescriptions also fell.
“Reduced access to medical care and disruptions in supply related to the pandemic may have decreased access to insulin, with possible adverse consequences for diabetes control,” the authors wrote.
Conversely, they wrote, as more people signed up for Medicaid due to job losses, the expanded access to telemedicine may have offset initial disruptions, at least for some patients.
The study of prescription data assessed insulin prescribing starting in January 2019 to establish a baseline. At total of 285,343 people were included in the analysis; the group had a mean age of 56.6 years and 51.9% were women. Periods covering major holidays were excluded from the analysis.
The baseline count for all existing prescriptions was 17,037.5 per week before the pandemic (range of 16,728.7-17,346.3). In the months before the pandemic, prescribing rose steadily by an average of 11.0 prescriptions per week (range of increase, 2.0-19.3). During the week that immediately followed the start of the pandemic, prescription counts fell 395.6 (–933.5 to 142.4); including a 139.2 drop in pediatric prescriptions.
However, pediatric prescribing recovered, and weekly counts for pediatric users are only down 1.2 prescriptions per week. Overall, insulin prescriptions are down 55.3 per week among existing patients; including 54.2 per week among adults. Prescriptions for new insulin users are down 14.0 prescriptions per week.
Data presented with the research letter show that insulin prescribing for both adult and pediatric users peaked just prior to the March 16 emergency. Prescriptions for adults reached around 17,500 per week, while the pediatric peak reached above 1150 per week, with prescriptions settling back to 1018 per week afterward.
“This study found a considerable decrease in the average number of weekly insulin prescription fills during the COVID-19 pandemic. Reduced contact with prescribing clinicians during the pandemic, rationing, previous stockpiling, or loss of insurance could explain the decline,” the authors wrote.
Despite the limitation of being able to adjust for mortality, they said, “We believe that these findings contribute to a better understanding of the association of the pandemic with insulin treatment for diabetes. Future studies should examine whether the pandemic was associated with adverse health outcomes associated with suboptimal insulin treatment.”