Willingness to take less medication for type 2 diabetes among older patients: The Diabetes & Aging Study.

BACKGROUND: To examine the willingness of older patients to take less diabetes medication (de-intensify) and to identify characteristics associated with willingness to de-intensify treatment. METHODS: Survey conducted in 2019 in an age-stratified, random sample of older (65-100 years) adults with diabetes on glucose-lowering medications in the Kaiser Permanente Northern California Diabetes Registry. We classified survey responses to the question: "I would be willing to take less medication for my diabetes" as willing, neutral, or unwilling to de-intensify. Willingness to de-intensify treatment was examined by several clinical characteristics, including American Diabetes Association (ADA) health status categories used for individualizing glycemic targets. Analyses were weighted to account for over-sampling of older individuals. RESULTS: A total of 1337 older adults on glucose-lowering medication(s) were included (age 74.2 ± 6.0 years, 44% female, 54.4% non-Hispanic white). The proportions of participants willing, neutral, or unwilling to take less medication were 51.2%, 27.3%, and 21.5%, respectively. Proportions of willing to take less medication varied by age (65-74 years: 54.2% vs. 85+ years: 38.5%) and duration of diabetes (0-4 years: 61.0% vs. 15+ years: 44.2%), both p < 0.001. Patients on 1-2 medications were more willing to take less medication(s) compared with patients on 10+ medications (62.1% vs. 46.6%, p = 0.03). Similar proportions of willingness to take less medications were seen across ADA health status, and HbA1c. Willingness to take less medication(s) was similar across survey responses to questions about patient-clinician relationships. CONCLUSIONS: Clinical guidelines suggest considering treatment de-intensification in older patients with longer duration of diabetes, yet patients with these characteristics are less likely to be willing to take less medication(s).

Lessons From Insulin: Policy Prescriptions for Affordable Diabetes and Obesity Medications.

Escalating insulin prices have prompted public scrutiny of the practices of drug manufacturers, pharmacy benefit managers, health insurers, and pharmacies involved in production and distribution of medications. As a result, a series of policies have been proposed or enacted to improve insulin affordability and foster greater equity in access. These policies have implications for other diabetes and obesity therapeutics. Recent legislation, at both the state and federal level, has capped insulin out-of-pocket payments for some patients. Other legislation has targeted drug manufacturers directly in requiring rebates on drugs with price increases beyond inflation rates, an approach that may restrain price hikes for existing medications. In addition, government negotiation of drug pricing, a contentious issue, has gained traction, with the Inflation Reduction Act of 2022 permitting limited negotiation for certain high expenditure drugs without generic or biosimilar competition, including some insulin products and other diabetes medications. However, concerns persist that this may inadvertently encourage higher launch prices for new medications. Addressing barriers to competition has also been a priority such as through increased enforcement against anticompetitive practices (e.g., "product hopping") and reduced regulatory requirements for biosimilar development and market entry. A novel approach involves public production, exemplified by California's CalRx program, which aims to provide biosimilar insulins at significantly reduced prices. Achieving affordable and equitable access to insulin and other diabetes and obesity medications requires a multifaceted approach, involving state and federal intervention, ongoing policy evaluation and refinement, and critical examination of corporate influences in health care.

Association Between Rental Assistance Programs and Undiagnosed Diabetes Among U.S.

BACKGROUND: Rental assistance programs have been linked to better housing quality, stability, healthcare access, and reduced likelihood of uncontrolled diabetes. However, its direct association with diabetes screening is uncertain. OBJECTIVE: To determine whether federal rental assistance programs are associated with lower odds of undiagnosed diabetes. DESIGN: We used a quasi-experimental approach, comparing outcomes among adults receiving rental assistance to those who entered assisted housing within 2 years after their health data were collected. We test the a priori hypothesis that rental assistance will be associated with decreased odds of undiagnosed diabetes. PARTICIPANTS: Participants in the National Health and Nutrition Examination Survey 1999-2018 who received rental assistance and who had diabetes. INTERVENTION: Current rental assistance participation, including specific housing programs. MAIN MEASURES: Undiagnosed diabetes based on having hemoglobin A1c ≥ 6.5% but answering no to the survey question of being diagnosed with diabetes. KEY RESULTS: Among 435 eligible adults (median age 54.5 years, female 68.5%, non-Hispanic white 32.5%), 80.7% were receiving rental assistance programs at the time of the interview, and 19.3% went on to receive rental assistance within 2 years. The rates of undiagnosed diabetes were 15.0% and 25.3% among those receiving rental assistance programs vs. those in the future assistance group (p-value = 0.07). In an adjusted logistic regression model, adults receiving rental assistance had lower odds of undiagnosed diabetes (OR 0.52, 95% CI 0.28-0.94) than those in future assistance groups. Sex, race and ethnic group, educational level, and poverty ratio were not significantly associated with having undiagnosed diabetes, but individuals aged 45-64 years had significantly lower odds of undiagnosed diabetes (OR 0.21, 95% CI 0.08-0.53) compared with those aged 18-44. CONCLUSIONS: Rental assistance was linked to lower odds of undiagnosed diabetes, suggesting that affordable housing programs can aid in early recognition and diagnosis, which may improve long-term outcomes.

Severe hypoglycemia and falls in older adults with diabetes: The Diabetes & Aging Study.

Objective: To estimate rates of severe hypoglycemia and falls among older adults with diabetes and evaluate their association. Research Design and Methods: Survey in an age-stratified, random sample adults with diabetes age 65-100 years; respondents were asked about severe hypoglycemia (requiring assistance) and falls in the past 12 months. Prevalence ratios (adjusted for age, sex, race/ethnicity) estimated the increased risk of falls associated with severe hypoglycemia. Results: Among 2,158 survey respondents, 79 (3.7%) reported severe hypoglycemia, of whom 68 (86.1%) had no ED visit or hospitalization for hypoglycemia. Falls were reported by 847 (39.2%), of whom 745 (88.0%) had no fall documented in outpatient or inpatient records. Severe hypoglycemia was associated with a 70% greater prevalence of falls (adjusted prevalence ratio = 1.7 (95% CI, 1.3-2.2)). Conclusion: While clinical documentation of events likely reflects severity or care-seeking behavior, severe hypoglycemia and falls are common, under-reported life-threatening events.

Glycemic control and diabetes complications across health status categories in older adults treated with insulin or insulin secretagogues: The Diabetes & Aging Study.

BACKGROUND: For older adults with type 2 diabetes (T2D) treated with insulin or sulfonylureas, Endocrine Society guideline recommends HbA1c between 7% to <7.5% for those in good health, 7.5% to <8% for those in intermediate health, and 8% to <8.5% for those in poor health. Our aim was to examine associations between attained HbA1c below, within (reference), or above recommended target range and risk of complication or mortality. METHODS: Retrospective cohort study of adults ≥65 years old with T2D treated with insulin or sulfonylureas from an integrated healthcare delivery system. Cox proportional hazards models of complications during 2019 were adjusted for sociodemographic and clinical variables. Primary outcome was a combined outcome of any microvascular or macrovascular event, severe hypoglycemia, or mortality during 12-month follow-up. RESULTS: Among 63,429 patients (mean age: 74.2 years, 46.8% women), 8773 (13.8%) experienced a complication. Complication risk was significantly elevated for patients in good health (n = 16,895) whose HbA1c was above (HR 1.97, 95% CI 1.62-2.41) or below (HR 1.29, 95% CI 1.02-1.63) compared to within recommended range. Among those in intermediate health (n = 30,129), complication risk was increased for those whose HbA1c was above (HR 1.45, 95% CI 1.30-1.60) but not those below the recommended range (HR 0.99, 95% CI 0.89-1.09). Among those in poor health (n = 16,405), complication risk was not significantly different for those whose HbA1c was below (HR 0.98, 95% CI 0.89-1.09) or above (HR 0.96, 95% CI 0.88-1.06) recommended range. CONCLUSIONS: For older adults with T2D in good health, HbA1c below or above the recommended range was associated with significantly elevated complication risk. However, for those in poor health, achieving specific HbA1c levels may not be helpful in reducing the risk of complications.

The Growing Role of Technology in the Care of Older Adults With Diabetes.

The integration of technologies such as continuous glucose monitors, insulin pumps, and smart pens into diabetes management has the potential to support the transformation of health care services that provide a higher quality of diabetes care, lower costs and administrative burdens, and greater empowerment for people with diabetes and their caregivers. Among people with diabetes, older adults are a distinct subpopulation in terms of their clinical heterogeneity, care priorities, and technology integration. The scientific evidence and clinical experience with these technologies among older adults are growing but are still modest. In this review, we describe the current knowledge regarding the impact of technology in older adults with diabetes, identify major barriers to the use of existing and emerging technologies, describe areas of care that could be optimized by technology, and identify areas for future research to fulfill the potential promise of evidence-based technology integrated into care for this important population.

Development and Validation of the Life Expectancy Estimator for Older Adults with Diabetes (LEAD): the Diabetes and Aging Study.

BACKGROUND: Estimated life expectancy for older patients with diabetes informs decisions about treatment goals, cancer screening, long-term and advanced care, and inclusion in clinical trials. Easily implementable, evidence-based, diabetes-specific approaches for identifying patients with limited life expectancy are needed. OBJECTIVE: Develop and validate an electronic health record (EHR)-based tool to identify older adults with diabetes who have limited life expectancy. DESIGN: Predictive modeling based on survival analysis using Cox-Gompertz models in a retrospective cohort. PARTICIPANTS: Adults with diabetes aged ≥ 65 years from Kaiser Permanente Northern California: a 2015 cohort (N = 121,396) with follow-up through 12/31/2019, randomly split into training (N = 97,085) and test (N = 24,311) sets. Validation was conducted in the test set and two temporally distinct cohorts: a 2010 cohort (n = 89,563; 10-year follow-up through 2019) and a 2019 cohort (n = 152,357; 2-year follow-up through 2020). MAIN MEASURES: Demographics, diagnoses, utilization and procedures, medications, behaviors and vital signs; mortality. KEY RESULTS: In the training set (mean age 75 years; 49% women; 48% racial and ethnic minorities), 23% died during 5 years follow-up. A mortality prediction model was developed using 94 candidate variables, distilled into a life expectancy model with 11 input variables, and transformed into a risk-scoring tool, the Life Expectancy Estimator for Older Adults with Diabetes (LEAD). LEAD discriminated well in the test set (C-statistic = 0.78), 2010 cohort (C-statistic = 0.74), and 2019 cohort (C-statistic = 0.81); comparisons of observed and predicted survival curves indicated good calibration. CONCLUSIONS: LEAD estimates life expectancy in older adults with diabetes based on only 11 patient characteristics widely available in most EHRs and claims data. LEAD is simple and has potential application for shared decision-making, clinical trial inclusion, and resource allocation.

Validation of a Hypoglycemia Risk Stratification Tool Using Data From Continuous Glucose Monitors.

This cohort study uses data from continuous glucose monitoring to validate a hypoglycemia risk stratification tool.

Data-driven classification of health status of older adults with diabetes: The diabetes and aging study.

BACKGROUND: We set out to identify empirically-derived health status classes of older adults with diabetes based on clusters of comorbid conditions which are associated with future complications. METHODS: We conducted a cohort study among 105,786 older (≥65 years of age) adults with type 2 diabetes enrolled in an integrated healthcare delivery system. We used latent class analysis of 19 baseline comorbidities to derive health status classes and then compared incident complication rates (events per 100 person-years) by health status class during 5 years of follow-up. Complications included infections, hyperglycemic events, hypoglycemic events, microvascular events, cardiovascular events, and all-cause mortality. RESULTS: Three health status classes were identified: Class 1 (58% of the cohort) had the lowest prevalence of most baseline comorbidities, Class 2 (22%) had the highest prevalence of obesity, arthritis, and depression, and Class 3 (20%) had the highest prevalence of cardiovascular conditions. The risk for incident complications was highest for Class 3, intermediate for Class 2 and lowest for Class 1. For example, the age, sex and race-adjusted rates for cardiovascular events (per 100 person-years) for Class 3, Class 2 and Class 1 were 6.5, 2.3, and 1.6, respectively; 2.1, 1.2, 0.7 for hypoglycemia; and 8.0, 3.8, and 2.3 for mortality. CONCLUSIONS: Three health status classes of older adults with diabetes were identified based on prevalent comorbidities and were associated with marked differences in risk of complications. These health status classes can inform population health management and guide the individualization of diabetes care.

Adjustment for Social Risk Factors in a Measure of Clinician Quality Assessing Acute Admissions for Patients With Multiple Chronic Conditions.

Importance: Adjusting quality measures used in pay-for-performance programs for social risk factors remains controversial. Objective: To illustrate a structured, transparent approach to decision-making about adjustment for social risk factors for a measure of clinician quality that assesses acute admissions for patients with multiple chronic conditions (MCCs). Design, Setting, and Participants: This retrospective cohort study used 2017 and 2018 Medicare administrative claims and enrollment data, 2013 to 2017 American Community Survey data, and 2018 and 2019 Area Health Resource Files. Patients were Medicare fee-for-service beneficiaries 65 years or older with at least 2 of 9 chronic conditions (acute myocardial infarction, Alzheimer disease/dementia, atrial fibrillation, chronic kidney disease, chronic obstructive pulmonary disease or asthma, depression, diabetes, heart failure, and stroke/transient ischemic attack). Patients were attributed to clinicians in the Merit-Based Incentive Payment System (MIPS; primary health care professionals or specialists) using a visit-based attribution algorithm. Analyses were conducted between September 30, 2017, and August 30, 2020. Exposures: Social risk factors included low Agency for Healthcare Research and Quality Socioeconomic Status Index, low physician-specialist density, and Medicare-Medicaid dual eligibility. Main Outcomes and Measures: Number of acute unplanned hospital admissions per 100 person-years at risk for admission. Measure scores were calculated for MIPS clinicians with at least 18 patients with MCCs assigned to them. Results: There were 4 659 922 patients with MCCs (mean [SD] age, 79.0 [8.0] years; 42.5% male) assigned to 58 435 MIPS clinicians. The median (IQR) risk-standardized measure score was 38.9 (34.9-43.6) per 100 person-years. Social risk factors of low Agency for Healthcare Research and Quality Socioeconomic Status Index, low physician-specialist density, and Medicare-Medicaid dual eligibility were significantly associated with the risk of hospitalization in the univariate models (relative risk [RR], 1.14 [95% CI, 1.13-1.14], RR, 1.05 [95% CI, 1.04-1.06], and RR, 1.44 [95% CI, 1.43-1.45], respectively), but the association was attenuated in adjusted models (RR, 1.11 [95% CI 1.11-1.12] for dual eligibility). Across MIPS clinicians caring for variable proportions of dual-eligible patients with MCCs (quartile 1, 0%-3.1%; quartile 2, >3.1%-9.5%; quartile 3, >9.5%-24.5%, and quartile 4, >24.5%-100%), median measure scores per quartile were 37.4, 38.6, 40.0, and 39.8 per 100 person-years, respectively. Balancing conceptual considerations, empirical findings, programmatic structure, and stakeholder input, the Centers for Medicare & Medicaid Services decided to adjust the final model for the 2 area-level social risk factors but not dual Medicare-Medicaid eligibility. Conclusions and Relevance: This cohort study demonstrated that adjustment for social risk factors in outcome measures requires weighing high-stake, competing concerns. A structured approach that includes evaluation of conceptual and contextual factors, as well as empirical findings, with active engagement of stakeholders can be used to make decisions about social risk factor adjustment.

Rental assistance improves food security and nutrition: An analysis of National Survey Data.

The U.S. is experiencing a severe housing affordability crisis, resulting in households having to make difficult trade-offs between paying for a place to live and basic health necessities such as food. Rental assistance may mitigate these strains, improving food security and nutrition. However, only one in five eligible individuals receive assistance, with an average wait time of two years. Existing waitlists create a comparable control group, allowing us to examine the causal impact of improved housing access on health and well-being. This national quasi-experimental study utilizes linked NHANES-HUD data (1999-2016) to investigate the impacts of rental assistance on food security and nutrition using cross-sectional regression. Tenants with project-based assistance were less likely to experience food insecurity (B = -0.18, p = 0.02) and rent-assisted individuals consumed 0.23 more cups of daily fruits and vegetables compared the pseudo-waitlist group. These findings suggest that the current unmet need for rental assistance and resulting long waitlists have adverse health implications, including decreased food security and fruit and vegetable consumption.

Navigating barriers to affording and obtaining insulin and diabetes supplies.

Highlights Our study suggests that people with diabetes (PWD) face issues of affording and obtaining insulin and diabetes supplies, even in a population predominantly on private health insurance. Financially independent young adults reported increased compensatory strategies and resulting perilous behaviors to ration or obtain insulin and supplies, indicating that additional issues may arise once transitioning into adulthood. This study suggests that improved access and affordability of insulin and diabetes supplies is needed to reduce the financial burden and prevent adverse outcomes among PWD.

Association Between Rental Assistance Programs and Hemoglobin A1c Levels Among US Adults.

Importance: Programs that provide affordable and stable housing, such as federal rental assistance, may be associated with improved mean blood glucose levels and related diabetes outcomes. Objective: To assess whether 2 different types of federal rental assistance programs are associated with glycated hemoglobin A1c (HbA1c) levels among middle-aged and older US adults. Design, Setting, and Participants: This cohort study used data from the National Health and Nutrition Examination Survey (NHANES) linked with US Department of Housing and Urban Development records of rental assistance participation. Adults aged 45 years or older who were receiving 2 types of rental assistance (project-based housing or housing vouchers) at the time of the NHANES interview and those who would receive rental assistance within the subsequent 2 years (waitlist group) were included. Data were collected from January 1999 to December 2016 and analyzed in October 2021. Exposures: Rental assistance participation, including project-based housing (subsidized housing developments including public housing) and housing vouchers (tenant-based subsidies for private market housing). Main Outcomes and Measures: The primary outcome was continuous HbA1c level, a common measure of blood glucose reflecting diabetes control. Linear regression was used to estimate the association between the 2 rental assistance programs and HbA1c level. Logistic regression was used to assess the association between rental assistance programs and HbA1c cut points (prediabetes: 5.7% to ≤6.5%; diabetes: >6.5%; uncontrolled diabetes: ≥9% [to convert to proportion of total Hb, multiply by 0.01]). Analyses used weights created by the National Center for Health Statistics that adjust for linkage eligibility. Results: Among 1050 adults in the study (41.6% aged ≥65 years; 70.1% female), 795 were receiving rental assistance at time of the NHANES interview (450 lived in project-based housing, and 345 had housing vouchers), and 255 received rental assistance within 2 years after the interview. Participants in project-based housing had lower HbA1c levels compared with individuals in the waitlist group (ß, -0.290; 95% CI, -0.599 to 0.020), but the difference was not significant. No significant differences in HbA1c levels were found between those receiving housing vouchers and those in the waitlist group (ß, 0.051; 95% CI, -0.182 to 0.284). Receiving project-based housing was associated with a reduced likelihood of uncontrolled diabetes (-3.7 percentage points; 95% CI, -7.0 to -0.0 percentage points) compared with being in the waitlist group. Conclusions and Relevance: In this cohort study of a nationally representative sample of US adults, living in project-based, federally subsidized housing was associated with a reduced likelihood of uncontrolled diabetes. The findings suggest that affordable housing programs may be associated with improved diabetes outcomes.

Catastrophic Spending On Insulin In The United States, 2017-18.

Insulin is considered an essential medicine for people with diabetes, but its price has doubled during the past decade, posing substantial financial barriers to patients in the US. In this article we describe out-of-pocket spending on insulin and consider risk factors that could contribute to the likelihood of a person experiencing catastrophic spending, defined as spending more than 40 percent of their postsubsistence family income on insulin alone. Using nationally representative data from the 2017 and 2018 Medical Expenditure Panel Surveys, we examined out-of-pocket spending on insulin among people who filled at least one insulin prescription. Among Americans who use insulin, 14.1 percent reached catastrophic spending over the course of one year, representing almost 1.2 million people. Nearly two-thirds of patients who experienced catastrophic spending on insulin were Medicare beneficiaries. Catastrophic spending was 61 percent less likely among Medicaid beneficiaries than among Medicare beneficiaries, suggesting that factors other than income, such as different types of insurance coverage, may influence catastrophic insulin spending. Policy reform is needed to curb out-of-pocket spending, especially for Medicare beneficiaries and people with low incomes, who appear to be particularly vulnerable to catastrophic spending.

Defining Minimum Necessary Communication During Care Transitions for Patients on Antihyperglycemic Medication: Consensus of the Care Transitions Task Force of the IPRO Hypoglycemia Coalition.

INTRODUCTION: Antihyperglycemic agents are significant contributors to adverse drug events, responsible for emergency department visits, hospitalizations, and death. Nationally, the rate of serious hypoglycemic events associated with these agents remains high despite widespread efforts to improve drug safety. Transitions of care between healthcare settings can lead to communication challenges between care professionals and increase the risk of adverse drug events. System-based improvements are needed to assure the safe transitions for patients with diabetes who are on antihyperglycemic agents. The objective of this study was to develop a consensus list of requisite elements that should be communicated between care settings during transitions of patients who are prescribed antihyperglycemic agents. METHODS: The Island Peer Review Organization (IPRO) Hypoglycemia Coalition identified suboptimal transitions of care as a barrier to improving patient safety and quality of diabetes care. The Coalition formed a multidisciplinary Task Force with experts in the field of diabetes care. The Task Force created a draft list of requisite communication elements through literature review and deliberation on monthly conference calls. A blinded iterative Delphi process was subsequently performed to generate a consensus list of requisite communication elements that participating experts agreed were necessary to safely and effectively assume the management of patients with diabetes upon care transitions. RESULTS: The Task Force completed a series of four iterative polls from September 2015 to August 2016, resulting in a final list of 22 requisite communication elements (the Diabetes Management Discharge Communication List), with the elements conceptually categorized into three domains: diagnosis and treatment, factors affecting glycemic control or patient risk, and patient self-management. CONCLUSIONS: The Diabetes Management Discharge Communication List provides an initial framework for the development of diabetes-specific resources to improve clinical communication between care settings.

Association Between Generic-to-Generic Levothyroxine Switching and Thyrotropin Levels Among US Adults.

IMPORTANCE: Switching among generic levothyroxine sodium products made by different manufacturers typically occurs at the pharmacy and may affect serum thyrotropin (TSH) levels. OBJECTIVE: To compare TSH levels between patients who continued taking the same sourced generic levothyroxine product and those who switched. DESIGN, SETTING, AND PARTICIPANTS: This comparative effectiveness research study with 1:1 propensity matching used data from OptumLabs Data Warehouse, a national administrative claims database linked to laboratory test results. Adults aged 18 years or older were included if they filled a generic levothyroxine prescription between January 1, 2008, and June 30, 2019, and had a stable drug dose, the same drug manufacturer, and a normal TSH level (0.3-4.4 mIU/L) for at least 3 months before either continuing to take the same product or switching among generic levothyroxine products (index date). Patients were excluded if they were pregnant, had diagnosed hypopituitarism or hyperthyroidism, or had a medical condition or used medications that could affect thyrotropin levels. They were also excluded if they filled a prescription for other forms of thyroid replacement therapy between 6 months before the index date and when the first TSH level was obtained 6 weeks to 12 months after the index date. Data were analyzed from December 1, 2019, to November 24, 2021. MAIN OUTCOMES AND MEASURES: Proportion of individuals with a normal (0.3-4.4 mIU/L) or markedly abnormal (<0.1 or >10.0 mIU/L) TSH level using the first available laboratory result 6 weeks to 12 months after the index date. A propensity score model was developed to minimize confounding using logistic regression with the binary outcome of continuing the same sourced levothyroxine product vs switching generic levothyroxine. Covariates were demographics, comorbidities, and baseline TSH level. The balance among the treatment groups was evaluated by comparing standardized mean differences of baseline covariates between the groups. RESULTS: A total of 15 829 patients filled generic levothyroxine (mean [SD] age, 58.9 [14.6] years; 73.4% [11 624] were women; 4.5% [705] were Asian, 10.2% [1617] were Black, 11.4% [1801] were Hispanic, and 71.4% [11 295] were White individuals); of these patients, 56.3% [8905] received a daily levothyroxine dose of 50 µg or less. A total of 13 049 patients (82.4%) continued taking the same sourced preparation, and 2780 (17.6%) switched among generic levothyroxine preparations. Among 2780 propensity-matched patient pairs, the proportion of patients with a normal TSH level after the index date was 82.7% (2298) among nonswitchers and 84.5% (2348) among switchers (risk difference, -0.018; 95% CI, -0.038 to 0.002; P = .07). The proportion of patients with a markedly abnormal TSH level after the index date was 3.1% (87) among nonswitchers and 2.5% (69) among switchers (risk difference, 0.007; 95% CI, -0.002 to 0.015; P = .14). The mean (SD) TSH levels after the index date were 2.7 (2.3) mIU/L among nonswitchers and 2.7 (3.3) mIU/L among switchers (P = .94). CONCLUSIONS AND RELEVANCE: Results of this comparative effectiveness research study suggest that switching among different generic levothyroxine products was not associated with clinically significant changes in TSH level. These findings conflict with the current guideline recommendation that warns clinicians about potential changes in TSH level associated with switching among levothyroxine products sourced from different manufacturers.

Rates of, and factors associated with, switching among generic levothyroxine preparations in commercially insured American adults.

IMPORTANCE: Some practice guidelines warn against generic L-thyroxine preparation switching. OBJECTIVE: To examine the rates of generic L-thyroxine preparation switching within one year of initiating L-thyroxine, and to examine factors associated with switching. DESIGN AND SETTING: Retrospective study using national data from a large administrative claims database from January 2008 through November 2018. PATIENTS: Medicare or commercially insured adults (≥18 years) who filled a generic L-thyroxine preparation. MAIN OUTCOME MEASURES: At least one switch from one generic L-thyroxine preparation to another within 1 year of L-thyroxine initiation defined by prescription fills. RESULTS: From January 2008 to November 2018, we included 483,390 patients who initiated generic L-thyroxine: mean (SD) age was 61.4 years (15.2), 75.2% were female, 72.6% were white. Within 1 year of initiating therapy, 98,013 (20%) switched to another L-thyroxine generic preparation at least once. In a multivariate logistic regression analysis, factors associated with switching included the number of pharmacies visited to fill L-thyroxine (>2 vs 1 adjusted OR [aOR] 7.15, 95% confidence interval [CI] 6.97-7.34), age ≥75 vs. <45 years (aOR 1.29, 95% CI 1.26-1.33), history of thyroid surgery (aOR 1.22, 95% CI 1.13-1.31), and first L-thyroxine fill date in 2018 vs. 2008 (aOR 3.32, 95% CI 3.14-3.51). CONCLUSIONS AND RELEVANCE: One in five patients switched among generic L-thyroxine manufacturers within one year of treatment initiation. Generic L-thyroxine switching occurred more often when more pharmacies were used to fill L-thyroxine. Given existing guideline recommendations, additional studies should clarify the impact of generic L-thyroxine switching on thyroid hormone values.