Differences in health outcomes associated with initial adherence to oral antidiabetes medications among veterans with uncomplicated Type 2 diabetes: a 5-year survival analysis

Estimating the effect of realistic improvements of metformin adherence on COVID-19 mortality using targeted machine learning

Background

Type 2 diabetes elevates the risk of severe outcomes in COVID-19 patients, with multiple studies reporting higher case fatality rates. Metformin is a widely used medication for glycemic management. We hypothesize that improved adherence to metformin may lower COVID-19 post-infection mortality risk in this group. Utilizing data from the Mexican Social Security Institute (IMSS), we investigate the relationship between metformin adherence and mortality following COVID-19 infection in patients with chronic metformin prescriptions.

Methods

This is a retrospective cohort study consisting of 61,180 IMSS beneficiaries who received a positive polymerase chain reaction (PCR) or rapid test for SARS-CoV-2 and had at least two consecutive months of metformin prescriptions prior to the positive test. The hypothetical intervention is improved adherence to metformin, measured by proportion of days covered (PDC), with the comparison being the observed metformin adherence values. The primary outcome is all-cause mortality following COVID-19 infection. We defined the causal parameter using shift intervention, an example of modified treatment policies. We used the targeted learning framework for estimation of the target estimand.

Findings

Among COVID-19 positive patients with chronic metformin prescriptions, we found that a 5% and 10% absolute increase in metformin adherence is associated with a respective 0.26% (95% CI: -0.28%, 0.79%) and 1.26% (95% CI: 0.72%, 1.80%) absolute decrease in mortality risk.

Interpretation

Subject to the limitations of a real-world data study, our results indicate a causal association between improved metformin adherence and reduced COVID-19 post-infection mortality risk.

Adherence to Oral Antidiabetic Drugs in Patients with Type 2 Diabetes: Systematic Review and Meta-Analysis

Poor adherence to oral antidiabetic drugs (OADs) in patients with type 2 diabetes (T2D) can lead to therapy failure and risk of complications. The aim of this study was to produce an adherence proportion to OADs and estimate the association between good adherence and good glycemic control in patients with T2D. We searched in MEDLINE, Scopus, and CENTRAL databases to find observational studies on therapeutic adherence in OAD users. We calculated the proportion of adherent patients to the total number of participants for each study and pooled study-specific adherence proportions using random effect models with Freeman-Tukey transformation. We also calculated the odds ratio (OR) of having good glycemic control and good adherence and pooled study-specific OR with the generic inverse variance method. A total of 156 studies (10,041,928 patients) were included in the systematic review and meta-analysis. The pooled proportion of adherent patients was 54% (95% confidence interval, CI: 51-58%). We observed a significant association between good glycemic control and good adherence (OR: 1.33; 95% CI: 1.17-1.51). This study demonstrated that adherence to OADs in patients with T2D is sub-optimal. Improving therapeutic adherence through health-promoting programs and prescription of personalized therapies could be an effective strategy to reduce the risk of complications.

Impact of Medication Adherence and Glycemic Control on the Risk of Micro- and Macrovascular Diseases in Patients with Diabetes

PURPOSE

Our purpose in the research was to clarify the impact of medication adherence to oral hypoglycemic agents during a 1-year period and subsequent glycemic control on the risk of micro- and macrovascular diseases.

METHODS

Examined was a nationwide claims database on 13,256 individuals with diabetic eye disease without requiring prior treatment, 7,862 without prior initiation of dialysis, 15,556 without prior coronary artery disease, 16,243 without prior cerebrovascular disease, and 19,386 without prior heart failure from 2008 to 2016 in Japan. Medication adherence was evaluated by the proportion of days covered. Patients were considered to have poor adherence if the proportion of days covered was <80%. Multivariate Cox regression model identified risks of micro- and macrovascular diseases.

RESULTS

In each group, mean age was 53 to 54 years, HbA1c was 7.1% to 7.2%, and median follow-up period was 4.6 to 5.1 years, and the percentage of poor adherence was approximately 30%. During the study period, 532 treatment-requiring diabetic eye disease, 75 dialysis, 389 coronary artery disease, 316 cerebrovascular disease, and 144 heart failure events occurred. Multivariate Cox regression model revealed that the hazard ratio (95% confidence interval) of dialysis in the poor adherence group was 2.04 (1.27-3.30) compared with the good adherence group. The hazard ratios in the poor adherence/poor glycemic control group were 3.34 (2.63-4.24) for treatment-requiring diabetic eye disease, 4.23 (2.17-8.26) for dialysis, 1.69 (1.23-2.31) for coronary artery disease, and 2.08 (1.25-3.48) for heart failure compared with the good adherence/good glycemic control group.

CONCLUSIONS

Poor medication adherence was an independent risk factor for the initiation of dialysis, suggesting that clinicians must pay close attention to these patients.

Adherence to and persistence with antidiabetic medications and associations with clinical and economic outcomes in people with type 2 diabetes mellitus: A systematic literature review

We designed a systematic literature review to identify available evidence on adherence to and persistence with antidiabetic medication in people with type 2 diabetes (T2D). Electronic screening and congress searches identified real-world noninterventional studies (published between 2010 and October 2020) reporting estimates of adherence to and persistence with antidiabetic medication in adults with T2D, and associations with glycaemic control, microvascular and/or macrovascular complications, hospitalizations and healthcare costs. Ninety-two relevant studies were identified, the majority of which were retrospective and reported US data. The proportions of patients considered adherent (median [range] 51.2% [9.4%-84.3%]) or persistent (median [range] 47.7% [16.9%-94.0%]) varied widely across studies. Multiple studies reported an association between greater adherence/persistence and greater reductions in glycated haemoglobin levels. Better adherence/persistence was associated with fewer microvascular and/or macrovascular outcomes, although there was little consistency across studies in terms of which outcomes were improved. More adherent and more persistent patients were typically less likely to be hospitalized or to have emergency department visits/admissions and spent fewer days in hospital annually than less adherent/persistent patients. Greater adherence and persistence were generally associated with lower hospitalization costs, higher pharmacy costs and lower or budget-neutral total healthcare costs compared with lower adherence/persistence. In conclusion, better adherence and persistence in people with T2D is associated with lower rates of microvascular and/or macrovascular outcomes and inpatient hospitalization, and lower or budget-neutral total healthcare expenditure. Education and treatment strategies to address suboptimal adherence and persistence are needed to improve clinical and economic outcomes.

Medication adherence in young adults with youth-onset type 2 diabetes: iCount, an observational study

AIMS

To assess prevalence of, and factors associated with, medication adherence of young adults with youth-onset type 2 diabetes.

METHODS

Oral hypoglycaemia agent (OHA) adherence was measured with unannounced telephone pill counts, insulin adherence was self-reported. Those taking ≥ 80% of pills/insulin were classified "high-adherent," <80% of pills/insulin "low-adherent." Analyses included unadjusted, and adjusted linear and logistic regressions assessing associations of participant factors with adherence.

RESULTS

For people taking OHAs (N = 212, mean age 26 yrs, 67% women, 18% non-Hispanic White, 35% non-Hispanic Black, 41% Hispanic), 69.8% were low-adherent. HbA1c was lower in the high-adherent group (9.2%/77 mmol/mol vs. 10.0%/86 mmol/mol, p < 0.04). More non-Hispanic Blacks were low-adherent (85.7%) than Hispanics (60.2%) and non-Hispanic whites (55.3%, p < 0.002); 91.4% of participants without healthcare coverage were low-adherent vs. 65.5% of those with coverage (p < 0.004). After adjustment, gender (p = 0.024), race/ethnicity (p < 0.001) and healthcare coverage (p = 0.001) remained related to OHA adherence. For insulin (N = 192), 37% were low-adherent. HbA1c was associated with insulin adherence (low = 11.2%/99 mmol/mol vs. high = 10.0%/86 mmol/mol, p < 0.001) with and without adjustment.

CONCLUSIONS

Young adults with youth-onset type 2 diabetes, especially females, non-Hispanic Blacks and those without healthcare coverage, commonly had low-OHA adherence. Glycaemic control was also poor. Interventions to improve medication adherence are needed for this vulnerable group.

Non-adherence to antidiabetic and cardiovascular drugs in type 2 diabetes mellitus and its association with renal and cardiovascular outcomes: A narrative review

Cardiovascular and renal complications are a major burden for individuals with type 2 diabetes mellitus (T2DM). Besides lifestyle interventions, current guidelines recommend combination drug therapy to prevent or delay the incidence and progression of comorbidities. However, non-adherence to pharmacotherapy is common in chronic conditions such as T2DM and a barrier to successful disease management. Numerous studies have associated medication non-adherence with worse outcome as well as higher health care costs. This narrative review provides (i) an overview on adherence measures used within and outside research settings, (ii) an estimate on the prevalence of non-adherence to antidiabetic and cardiovascular drugs in T2DM, and (iii) specifically focuses on the association of non-adherence to these drugs with renal and cardiovascular outcomes.

Treatment Patterns and Persistence With GLP-1 RA Treatments Among Patients With Type 2 Diabetes in France: A Retrospective Cohort Analysis

INTRODUCTION

In type 2 diabetes (T2D), persistence with injectable glucose-lowering therapy is associated with better outcomes. This study used real-world pharmacy data to report on persistence with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with T2D in France.

METHODS

This retrospective cohort analysis presents longitudinal data from approximately 7500 French retail pharmacies that filled GLP-1-RA prescriptions for GLP-1 RA-naïve patients with T2D ('index therapy': dulaglutide; once-weekly exenatide [exenatide QW]; twice-daily exenatide [exenatide BID]; liraglutide) between January 2015 and December 2016 (follow-up ≥ 12 months). The main outcome was treatment persistence (absence of discontinuation [gap following index therapy prescription ≥ 2-fold the expected duration of that prescription] or switch [new non-index glucose-lowering prescription issued ≤ 30 days before/after index therapy discontinuation]). Persistence was calculated as the median duration through Kaplan-Meier survival analysis over the variable follow-up period and as the proportion of patients persistent at 12 months. In addition to persistence outcomes (discontinuation/switch), three other treatment modifications were assessed: augmentation/intensification with a new non-index glucose-lowering therapy; off-label dose increase (daily dose > 20 μg for exenatide BID; two consecutive prescriptions with daily dose > 1.8 mg for liraglutide); and off-label dose decrease (two consecutive prescriptions with average daily dose lower than the index dose). Off-label dose changes were not assessed for dulaglutide or exenatide QW (as single-dose, prefilled pens).

RESULTS

Median persistence was longest for dulaglutide (373 days) versus liraglutide (205 days), exenatide QW (184 days) and exenatide BID (93 days). Twelve months after treatment initiation, the percentage of persistent patients ranged from 51% (dulaglutide) to 21% (exenatide BID). Overall, treatment modification occurred less commonly for dulaglutide than for the other index GLP-1 RAs.

CONCLUSION

This analysis revealed marked differences in persistence among GLP-1 RAs, which was highest for dulaglutide and lowest for exenatide BID. The prospective TROPHIES study will provide additional information about persistence with dulaglutide and liraglutide, including reasons for treatment modifications.

Glucagon-Like Peptide 1 Receptor Agonists in Type 2 Diabetes Mellitus: Data from a Real-World Study in Spain

INTRODUCTION

This study aimed to describe utilization patterns, persistence, resource utilization and costs in patients with type 2 diabetes mellitus initiating treatment with glucagon-like peptide 1 receptor agonists in routine clinical practice in Spain.

METHODS

This retrospective study of medical records in the Big-Pac database identified adults starting treatment with once-weekly (QW) dulaglutide, exenatide-QW or once-daily liraglutide between 1 November 2015 and 30 June 2017. Patients were followed for up to 18 months from treatment initiation. Data on clinical characteristics of patients, treatment patterns, average daily dose and costs were obtained for the three cohorts. Persistence over the 18-month period was evaluated using Kaplan-Meier curves. All analyses were descriptive.

RESULTS

A total of 1402 patients were included in this study (dulaglutide [n = 492], exenatide-QW [n = 438] or liraglutide [n = 472]); 52.8% were men, and the mean (SD) age was 62 (11) years, glycated haemoglobin (HbA1c) was 8.1% (1.2) and body mass index was 35.5 (3.2) kg/m² at treatment initiation. Persistence at 18 months was 59.1% (95% confidence interval [CI] 54.8-63.4) for dulaglutide, 45.7% (95% CI 41.0-50.4) for exenatide-QW and 46.6% (95% CI 42.1-51.1) for liraglutide. The average (SD) dose was 1.2 (0.4) mg/week for dulaglutide, 1.9 (0.3) mg/week for exenatide-QW and 1.1 (0.3) mg/day for liraglutide. The average reduction in HbA1c levels at 1 year was - 0.68% for patients who initiated dulaglutide, - 0.54% for patients who initiated exenatide-QW and - 0.50% for patients who initiated liraglutide. The mean (SD) total annual health care costs were €4072 (1946) for dulaglutide, €4418 (2382) for exenatide-QW and €4382 (2389) for liraglutide.

CONCLUSION

Results suggest that patients who started treatment with dulaglutide had higher persistence over 18 months, presented lower HbA1c levels at 12 months and incurred lower annual total healthcare costs than patients who initiated exenatide-QW or liraglutide.

Racial and Regional Disparities in Outcomes Among Veterans Initially Adherent to Oral Antidiabetic Therapies: an Observational Cohort Study

BACKGROUND

Adherence to prescribed medications is connected with, but is not a guarantee of, improved disease management and health outcomes. It remains unclear whether underlying health disparities exist among patients adherent to therapy and whether differences in outcomes vary by race and residential areas of the country.

OBJECTIVE

To determine the extent of racial and regional variation in outcomes within 5 years of oral antidiabetic drug initiation among veterans adherent to therapy.

DESIGN

Retrospective cohort study of 83,265 US Veterans Health Administration data, 2002-2014 PATIENTS: US veterans with uncomplicated diabetes and taking oral antidiabetic agents MAIN MEASURES: Veterans initially adherent to oral antidiabetic therapy were followed for up to 5 years, and comparisons focused on differences between non-Hispanic White and non-Hispanic Black veterans across geographic region and residential type (urban or rural). Outcomes included composite cardiovascular events, composite cerebrovascular events, or all-cause mortality using Poisson and adjusted Cox proportional hazards models.

KEY RESULTS

Cardiovascular event and all-cause mortality rates differed by race and region, while urban/rural differences were evident for cerebrovascular events and all-cause mortality. For non-Hispanic Blacks, the mortality rate was half that compared to non-Hispanic Whites (6.5 [95% CI 5.8-7.2] versus 13.3 [95% CI 12.9-13.8], p < 0.0001). Compared to the Northeast, all other regions had higher adjusted hazards for cardiovascular or cerebrovascular events (with a single exception), but no regional differences in all-cause mortality were observed. Models with interactions demonstrated that racial differences in cardiovascular events and all-cause mortality were isolated to the Midwest (HR 1.99 [95% CI 1.301-3.06; HR 1.64 [95% CI 1.210-2.215]) and South (HR 1.69 [85% CI 1.347-2.131]; HR 1.27 [95% CI 1.095-1.470]).

CONCLUSIONS

Despite adherence to therapy, differences in outcomes are likely among veterans with diabetes based on race and geography. Localized analyses may uncover specific social determinants contributing to differences in outcomes.

Oral antidiabetic medication adherence and glycaemic control among patients with type 2 diabetes mellitus: a cross-sectional retrospective study in a tertiary hospital in Saudi Arabia

OBJECTIVES

The purpose of this study is to measure the adherence rates of oral antidiabetic drugs (OADs) in patients with type 2 diabetes mellitus (T2DM) and assess the relationship of glycaemic control and adherence to OADs after controlling for other associated factors.

DESIGN

Cross-sectional retrospective study.

SETTING

Large tertiary hospital in the central region of Saudi Arabia.

PARTICIPANTS

5457patients aged 18 years and older diagnosed with T2DM during the period from 1 January 2016 to 31 December 2016.

PRIMARY AND SECONDARY OUTCOME MEASURES

The modified medication possession ratio (mMPR) was calculated as a proxy measure for adherence of OADs. The factors associated with OADs non-adherence and medication oversupply were assessed using multinomial logistic regression models. The secondary outcomes were to measure the association between OADs adherence and glycaemic control.

RESULTS

Majority of patients with T2DM were females (n=3400, 62.3%). The average glycated haemoglobin was 8.2±1.67. Among the study population, 48.6% had good adherence (mMPR >0.8) and 8.6% had a medication oversupply (mMPR >1.2). Good adherence was highest among those using repaglinide (71.0%) followed by pioglitazone (65.0%) and sitagliptin (59.0%). In the multivariate analysis, women with T2DM were more likely to have poor adherence (adjusted OR (AOR)=0.76, 95% CI=0.67, 0.86) compared with men. Also, medication oversupply was more likely among patients with hyperpolypharmacy (AOR=1.88, 95% CI=1.36, 2.63), comorbid osteoarthritis (AOR=1.72, 95% CI=1.20, 02.45) and non-Saudi patients (AOR=1.53, 95% CI=1.16, 2.01). However, no association was found between glycaemic control and adherence to OADs.

CONCLUSION

The study findings support the growing concern of non-adherence to OADs among patients with T2DM in Saudi Arabia. Decision makers have to invest in behavioural interventions that will boost medication adherence rates. This is particularly important in patients with polypharmacy and high burden of comorbid conditions.

Lack of Treatment Persistence and Treatment Nonadherence as Barriers to Glycaemic Control in Patients with Type 2 Diabetes

Treatment persistence (continuing to take medication for the prescribed period) and treatment adherence (complying with the prescription in terms of drug schedules and dosage) are both important when treating chronic diseases such as type 2 diabetes (T2D). They can be indicators of patient satisfaction with treatment. In T2D, the achievement of optimal outcomes requires both persistence with and adherence to prescribed therapy. Poor persistence with and adherence to T2D medication can have profound consequences for the patient, including non-achievement of glycaemic goals and an increased risk of long-term complications and mortality. Therefore, poor treatment persistence and adherence may also have economic consequences, including increased healthcare resource utilization and healthcare costs. Treatment persistence and adherence are affected by several factors, including the mode of administration, administration frequency/regimen complexity, and patient expectations. The aims of this review are as follows: to provide an overview of persistence with and adherence to different antidiabetes therapies for patients with T2D in the real-world setting; examine factors contributing to poor treatment persistence and adherence; and assess available data on the impact of poor treatment persistence and/or adherence on clinical and economic outcomes. Numerous potential targets for improving treatment persistence and/or adherence are identified, including developing less complex treatment regimens with lower pill burdens or less frequent injections, improving the convenience of drug-delivery systems, such as the use of insulin pen devices rather than the conventional vial and syringe, and developing therapies with an improved safety profile to alleviate patient fears of adverse effects, such as weight gain and risk of hypoglycaemia.Funding: Sanofi.