Adults with mainly type 2 diabetes had gaps in the use of medications for managing blood glucose, hypertension, and lipids, in an analysis of nationally representative US survey data.
A mean of 19.5%, 17.1%, and 43.3% of survey participants had inconsistent use of glucose-, blood pressure-, or lipid-lowering medications, respectively, over 2 years in a series of successive 2-year surveys in 2005-2019.
A new group of participants was enrolled for each successive 2-year survey.
"We found persistent and sometimes increasing gaps in continuity of use of these [glycemia, hypertension, and lipid] treatments at the national level," the researchers summarize.
Moreover, "this outcome was found despite long-lasting guidelines that generally recommend medications as an ongoing part of therapy for adults with type 2 diabetes to reduce macrovascular and microvascular disease risk," they stress.
The data did not distinguish between type 1 and type 2 diabetes, but more than 90% of diabetes diagnoses in the United States are type 2 diabetes, the researchers note.
Therefore, it is "correct, our findings primarily reflect type 2 diabetes," lead author Puneet Kaur Chehal, PhD, assistant professor, Rollins School of Public Health, Emory University, Atlanta, clarified in an email to Medscape Medical News.
"The clinical guidelines for treatment of type 1 diabetes are distinct," she added, so "it is difficult to draw any conclusions from our study for this population."
"To observe national trends in continuous use decrease at the same time that diabetes complications are increasing and physicians are guided to shift away from treat-to-target and towards individual patient needs certainly caught our attention," she said.
"Our findings highlight the need for additional research to understand what is going on here," according to Chehal.
"We did not observe levels of glucose (or blood pressure and lipids) to explore if the decrease in glucose-lowering drugs was warranted," she added.
"Our evidence of differences in continuity in use across subgroups (by race/ethnicity, payer, and age) does warrant further analysis of whether the decreasing trends we observe are lapses in access or deliberate changes in treatment."
The study was published online January 30 in JAMA Network Open.
Investigating Trends in Medication Adherence
Type 2 diabetes is a chronic condition and medications to control blood glucose, blood pressure, and lipids lower the risk of diabetes-associated complications, Chehal and colleagues note.
After years of improvement, these cardiometabolic parameters plateaued and even decreased in 2013-2021, in parallel with increasing rates of diabetes complications, especially in younger adults, certain ethnic minority groups, and people with increased risks.
Suboptimal medication adherence among people with type 2 diabetes is associated with preventable complications and onset of heart disease, kidney disease, or diabetic neuropathy, which can lead to amputation.
However, previous studies of medication adherence were typically limited to patients covered by Medicare or commercial insurance, or studies only had 1-year follow-up.
Therefore, the researchers performed a cross-sectional analysis of a series of 2-year data from the Medical Expenditure Panel Survey (MEPS), in which participants reply to five interviews in 2 years and new participants are selected each year.
Researchers analyzed data from 15,237 adults aged 18 and older with type 2 diabetes who participated in one of fourteen 2-year MEPS survey panels in 2005-2019.
About half of participants (47.4%) were age 45-64 and about half (54.2%) were women.
They were racially diverse (43% non-Latino White, 25% Latino, and 24% non-Latino Black).
Participants were classified as having "inconsistent use" of glucose-lowering medication, for example, if they did not fill at least one prescription for a glucose-lowering drug in each of the 2 years.
"As long as [the medication] was some type of glucose, blood pressure, or lipid-lowering medication and was filled, it counted as continued use for that category," Chehal explained.
They are preparing another paper that explores changes in medication regimens.
The current study showed:
Continued use of glucose-lowering medication in both years decreased from 84.5% in 2005-2006 to 77.4% in 2018-2019.
No use of glucose-lowering medication in either of the 2 years increased from 8.1% in 2005-2006 to 12.9% in 2018-2019.
Inconsistent use of glucose-lowering medication increased from 3.3% in 2005-2006 to 7.1% in 2018-2019.
New use of glucose-lowering medications in year 2 fluctuated between 2% and 4% across panels.
Inconsistent use of blood pressure-lowering medication increased from 3.9% in 2005-2006 to 9.0% in 2016-2017.
Inconsistent use of lipid-lowering medication increased to a high of 9.9% in 2017-2018.
Younger and Black participants were less likely to consistently use glucose-lowering medication, Latino patients were less likely to consistently use blood pressure-lowering medications, and Black and Latino patients were less likely to continuously use lipid-lowering medications. Uninsured adults were more likely to use no medications or use medications inconsistently.
"Changes and inconsistencies in payer formularies and out-of-pocket cost burden, especially among adults with no or insufficient insurance (ie, Medicare Part D), remain prominent issues," according to Chehal and colleagues.
"Decreases in continuity in use of glucose-lowering medications in recent panels may explain worsening diabetes complications," they write.
This may be partly due to recommended decreases in sulfonylurea and thiazolidinedione use and increased prescribing of new and more cost-prohibitive medications, they suggest.
Or this may be due to the shift away from treating aggressively until a target is achieved toward individualizing treatment based on a patient's age, phenotype, or comorbidities (eg, kidney disease).
The study was supported by a grant from MSD, a subsidiary of Merck, to the Rollins School of Public Health. Some of the researchers received grants from Merck for the submitted work or were partially supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health to the Georgia Center for Diabetes Translation Research. Chehal has reported no relevant financial relationships. Disclosures for the other authors are listed with the article.
JAMA Netw Open. Article. Published online January 30, 2023.
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