Effect of medication adherence on long-term all-cause-mortality and hospitalization for cardiovascular disease in 65,067 newly diagnosed type 2 diabetes patients

This study determined the effects of anti-diabetic medication adherence on the long-term all-cause mortality and hospitalization for cerebrovascular disease and myocardial infarction among newly diagnosed patients. The study used retrospective cohort from the National Health Insurance Service. Study participants were 65,076 newly diagnosed type 2 diabetes mellitus patients aged ≥40 years. The medication adherence was evaluated from the proportion of days covered (PDC) between 2006 and 2007. Outcome variables were mortality, newly diagnosed cerebrovascular disease (CVD) and myocardial infarction (MI) in 2008–2017. Cox-proportional hazard regression analysis was performed. After adjusting for sex, age, monthly contribution, insurance type, medical institution type, Charlson comorbidity index score, disability, hypertension, and active ingredients of oral hypoglycemic agents, the adjusted hazard ratio (aHR) for all-cause-mortality of the lowest PDC group (<0.20) was 1.45 (95% confidence interval [CI] = 1.36–1.54) as compared to the highest PDC (≥0.8). The aHR for all-cause-mortality associated with PDC levels of 0.60–0.79, 0.40–0.59, and 0.20–0.39 were 1.19, 1.26, and 1.34, respectively (P_trend < 0.001). Compared to the highest PDC group, diabetic patients with the lowest PDC had elevated risk for CVD (aHR = 1.41; 95% CI = 1.30–1.52; P_trend < 0.001). Improving anti-diabetic medication adherence among newly diagnosed type 2 diabetes mellitus patients is essential to the reduce risk for cardiovascular disease and long-term all-cause mortality.

Association Between Adherence to Pharmacotherapy and Outcomes in Type 2 Diabetes: A Meta-analysis

OBJECTIVE

A previous study suggests an association between poor medication adherence and excess mortality in chronic disease. The purpose of this study was to assess the association between medication adherence and risk of cardiovascular disease (CVD), all-cause mortality, and hospitalization in type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted an electronic search on many electronic databases from inception to 27 April 2016. We selected randomized controlled trials and case-control and cohort studies reporting on CVD, all-cause mortality, or hospitalization outcomes by adherence in adults with type 2 diabetes. Two reviewers independently screened for eligible studies and extracted outcome data. Pooled relative risks (RRs) were calculated using a random-effects meta-analysis; risk of bias in each of the included studies was assessed using the GRADE approach.

RESULTS

Eight observational studies were included (n = 318,125). The mean rate of poor adherence was 37.8% (95% CI 37.6-38.0). Adjusted estimates were provided by five studies only. The RRs of good (≥80%) versus poor adherence to medication were 0.72 (95% CI 0.62-0.82, I² = 0%, three studies) for all-cause mortality and 0.90 (0.87-0.94, I² = 63%, seven studies) for hospitalization. No evidence of small study bias was observed. Only one study reported CVD outcomes by adherence.

CONCLUSIONS

We identified no trials reporting on outcomes by adherence, suggesting a systematic failure to include this information. Pooled estimates from available observational studies suggest that good medication adherence is associated with reduced risk of all-cause mortality and hospitalization in people with type 2 diabetes, although bias cannot be excluded as an explanation for these findings.

Cost-Effectiveness of Saxagliptin versus Acarbose as Second-Line Therapy in Type 2 Diabetes in China

Objective

This study assessed the long-term cost-effectiveness of saxagliptin+metformin (SAXA+MET) versus acarbose+metformin (ACAR+MET) in Chinese patients with type 2 diabetes mellitus (T2DM) inadequately controlled on MET alone.

Methods

Systematic literature reviews were performed to identify studies directly comparing SAXA+MET versus ACAR+MET, and to obtain diabetes-related events costs which were modified by hospital surveys. A Cardiff Diabetes Model was used to estimate the long-term economic and health treatment consequences in patients with T2DM. Costs (2014 Chinese yuan) were calculated from the payer’s perspective and estimated over a patient’s lifetime.

Results

SAXA+MET predicted lower incidences of most cardiovascular events, hypoglycemia events and fatal events, and decreased total costs compared with ACAR+MET. For an individual patient, the quality-adjusted life-years (QALYs) gained with SAXA+MET was 0.48 more than ACAR+MET at a cost saving of ¥18,736, which resulted in a cost saving of ¥38,640 per QALY gained for SAXA+MET versus ACAR+MET. Results were robust across various univariate and probabilistic sensitivity analyses.

Conclusion

SAXA+MET is a cost-effective treatment alternative compared with ACAR+MET for patients with T2DM in China, with a little QALYs gain and lower costs. SAXA is an effective, well-tolerated drug with a low incidence of adverse events and ease of administration; it is anticipated to be an effective second-line therapy for T2DM treatment.

Cost-Effectiveness of Dapagliflozin versus Acarbose as a Monotherapy in Type 2 Diabetes in China

OBJECTIVE

To estimate the long-term cost-effectiveness of dapagliflozin versus acarbose as monotherapy in treatment-naïve patients with type 2 diabetes mellitus (T2DM) in China.

METHODS

The Cardiff Diabetes Model, an economic model designed to evaluate the cost-effectiveness of comparator therapies in diabetes was used to simulate disease progression and estimate the long-term effect of treatments on patients. Systematic literature reviews, hospital surveys, meta-analysis and indirect treatment comparison were conducted to obtain model-required patient profiles, clinical data and costs. Health insurance costs (2015¥) were estimated over 40 years from a healthcare payer perspective. Univariate and probabilistic sensitivity analyses were performed.

RESULTS

The model predicted that dapagliflozin had lower incidences of cardiovascular events, hypoglycemia and mortality events, was associated with a mean incremental benefit of 0.25 quality-adjusted life-years (QALYs) and with a lower cost of ¥8,439 compared with acarbose. This resulted in a cost saving of ¥33,786 per QALY gained with dapagliflozin. Sensitivity analyses determined that the results are robust.

CONCLUSION

Dapagliflozin is dominant compared with acarbose as monotherapy for Chinese T2DM patients, with a little QALY gain and lower costs. Dapagliflozin offers a well-tolerated and cost-effective alternative medication for treatment-naive patients in China, and may have a direct impact in reducing the disease burden of T2DM.

Persistence and adherence to oral antidiabetics: a population-based cohort study

AIMS

A population-based cohort study design was used to estimate persistence rate, re-initiation rate after discontinuation, and adherence level among incident users of oral antidiabetics (OADs), and to investigate predictors of non-persistence and non-adherence.

METHODS

Incident OAD users were identified using healthcare databases of residents covered by the public drug insurance plan of the Province of Quebec, Canada. Patients initiated OAD therapy between January 2000 and October 2009 and were aged 45-85 years at cohort entry. Persistence rate, re-initiation after discontinuation, and adherence level were assessed over 2 years. Predictors of non-persistence and non-adherence were analyzed using Cox and logistic regression models, respectively.

RESULTS

The cohort included 160,231 incident OAD users at entry. One year after OAD initiation, persistence rate was 51 % and adherence level 67 %. Among those deemed non-persistent, 80.6 % re-initiated OAD therapy within 12 months of discontinuation; a proportion increasing with primary persistence duration. The 1-year persistence rate varied according to OAD classes; being the highest for thiazolidinediones (62 %) and the lowest for alpha-glucosidase inhibitors (30 %). The likelihood for non-persistence was 39-54 % higher when drug copayments were required. Conversely, OAD discontinuation was least likely for patients with schizophrenia [hazard ratio 0.70 (95 % CI 0.67-0.73)], dyslipidemia [0.85 (0.84-0.87)], anticoagulation [0.86 (0.83-0.88)], hypertension [0.87 (0.85-0.88)], and ≥7 medications [0.90 (0.88-0.91)]. Predictors of non-adherence were similar.

CONCLUSIONS

Non-persistence and non-adherence to OAD therapy were common, although re-initiation rate was high. OAD classes, drug copayments, comorbidities and co-medications may help identifying those who were more likely to benefit from counseling.

Retrospective analysis of long-term adherence to and persistence with DPP-4 inhibitors in US adults with type 2 diabetes mellitus

Introduction

Patients with type 2 diabetes mellitus (T2DM) must remain adherent and persistent on antidiabetic medications to optimize clinical benefits. This analysis compared adherence and persistence among adults initiating dipeptidyl peptidase-4 inhibitors (DPP-4is), sulfonylureas (SUs), and thiazolidinediones (TZDs) and between patients initiating saxagliptin or sitagliptin, two DPP-4is.

Methods

This retrospective cohort study utilized the US MarketScan^® (Truven Health Analytics, Ann Arbor, MI, USA) Commercial and Medicare Supplemental health insurance claims databases. Adults aged ≥18 years with T2DM who initiated a DPP-4i, SU, or TZD from January 1, 2009 to January 31, 2012 were included. Patients must have been continuously enrolled for ≥1 year prior to and ≥1 year following initiation. Adherence was measured using proportion of days covered (PDC), with PDC ≥ 0.80 considered adherent. Persistence was measured as time to discontinuation, defined as last day with drug prior to a 60+ days gap in therapy. Multivariable logistic regression and Cox proportional hazards models compared the outcomes between cohorts, controlling for baseline differences.

Results

The sample included 238,372 patients (61,399 DPP-4i, 134,961 SU, 42,012 TZD). During 1-year follow-up, 47.3% of DPP-4i initiators, 41.2% of SU initiators, and 36.7% of TZD initiators were adherent. Adjusted odds of adherence were significantly greater among DPP-4i initiators than SU (adjusted odds ratio [AOR] = 1.678, P < 0.001) and TZD initiators (AOR = 1.605, P < 0.001). During 1-year follow-up, 55.0% of DPP-4i initiators, 47.8% of SU initiators, and 42.9% of TZD initiators did not discontinue therapy. Adjusted hazards of discontinuation were significantly greater for SU (adjusted hazard ratio [AHR] = 1.390, P < 0.001) and TZD initiators (AHR = 1.402, P < 0.001) compared with DPP-4i initiators. Saxagliptin initiators had significantly better adherence (AOR = 1.213, P < 0.001) compared with sitagliptin initiators, and sitagliptin initiators had significantly greater hazard of discontinuation (AHR = 1.159, P < 0.001). Results were similar over a 2-year follow-up.

Conclusions

US adults with T2DM who initiated DPP-4i therapy, particularly saxagliptin, had significantly better adherence and persistence compared with patients who initiated SUs or TZDs.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0171-3) contains supplementary material, which is available to authorized users.

Estimating the Impact of Oral Diabetes Medication Adherence on Medical Costs in VA

Background. Despite evidence demonstrating clinical benefits of oral hypoglycemic agents (OHAs), adherence to OHAs is generally poor. The economic benefit of OHA adherence among patients in the Veterans Affairs Health System (VA) is unknown. Objective. This study assessed the impact of OHA adherence on medical costs and hospitalization probability in a VA population. Methods. This retrospective cohort study included 26 051 VA patients with diabetes who completed the 2006 Survey of Health Care Experiences of Patients. We calculated total costs in fiscal year (FY) 2007 from the VA perspective as the sum of costs for all inpatient and outpatient services provided by VA. We measured adherence using the medication possession ratio (MPR), which reflected the proportion of days covered in FY2007. Patients were classified as adherent if MPR ≥80%. Analyses using instrumental variables (IVs) addressed potential biases from unobserved confounding. Results. On average, adherent patients incurred lower total medical costs ($4051 vs $5133, P < 0.001) and were less likely to be hospitalized (4.6% vs 7.2%, P < 0.001) compared with nonadherent patients. After covariate adjustment, adherence was associated with a $170 reduction in total costs ( P < 0.011) and a 1.5 percentage point decrease ( P < 0.001) in hospitalization probability. IV estimates indicated that the impacts of OHA adherence were larger in magnitude. Conclusion. On average, OHA adherence was associated with lower medical costs of at least $170 per patient over a 1-year period. Results from this study are important for informing policy decisions to broadly disseminate programs to promote diabetes medication adherence, particularly in a VA setting.

How to use pharmacy claims data to measure patient nonadherence? The example of oral diabetics in therapy of type 2 diabetes mellitus

INTRODUCTION

The purpose of this study was to describe the methodological framework underlying nonadherence (NA) measurement based on pharmacy claims data, its quantitative impact on the results of NA studies, and to identify those methodological categories most likely to explain diabetes-related clinical outcomes. We use the example of oral antidiabetics in the treatment of diabetes mellitus type 2; 113,108 patients derived from a German statutory health insurance fund were analyzed.

METHODS

We identified 12 methodological categories as pervasive features in pharmacy claims data based NA analyses. The influence of the different methodological categories and their parameters on analysis results was tested using sensitivity analysis. To validate alternative methodological framework options, we performed multivariate logistical regression estimates using diabetes-related hospitalization/clinical events as a combined dichotomized dependent variable.

RESULTS

The choice of parameters within the identified 12 methodological categories available has exceptional impact on the results of pharmacy data based claims NA analyses. When the full range of theoretically possible cases is considered in our sample, it can be seen that the resulting NA range is between 15.7% and 97.0%. The definition of the required daily dose, the decision to use either a prescription-/interval-based approach, and the classes of medication analyzed exert a notable influence on the study results. In our analysis, 69.4% of the 216 different study design options analyzed significantly explain the likelihood of diabetes-related clinical events.

CONCLUSIONS

We recommend strongly that methodological transparency is awarded a much more important role in the conduct of NA analyses made on the basis of pharmacy claims data.

Adherence and persistence to a regimen of basal insulin in a pre-filled pen compared to vial/syringe in insulin-naïve patients with type 2 diabetes

OBJECTIVE

This study was conducted to compare adherence and persistence of patients initiating basal insulin therapy with Levemir FlexPen versus those initiating basal insulin therapy with NPH via vial and syringe.

MATERIALS AND METHODS

Data were gathered from a large US retrospective claims database, and included patients with type 2 diabetes that initiated basal insulin therapy with either Levemir FlexPen or NPH in vials. Patients were defined as adherent to therapy if they had a medication possession ratio (MPR) of ≥80% in the 12-month follow-up period and were defined as persistent with therapy if they had no gaps in insulin therapy in the follow-up period.

RESULTS

After controlling for confounders using logistic regression, patients initiating therapy with Levemir FlexPen had 39% higher adjusted odds of achieving an MPR ≥80% versus patients initiating therapy with NPH vial (OR 1.39; 95% CI: 1.04-1.85). Analysis of persistence using a Cox proportional hazards model indicated that patients initiating Levemir FlexPen had a 38% lower hazard of discontinuation compared to NPH vial (HR 0.62, 95% CI: 0.55-0.70).

LIMITATIONS

Claims-based studies are limited to the extent that they accurately capture medical and pharmacy use. Also, relying on claims-based data limits the generalizability of the findings to similar populations and treatments.

CONCLUSIONS

These results suggest that persistence and adherence with insulin may be improved for patients initiating basal insulin therapy with Levemir FlexPen versus NPH vial.

Emergency department care of seizure patients: demographic trends in southern Arizona

The aim of this study was to describe the epidemiology of epilepsy and characteristics of patients with seizures who presented at the Yuma Regional Medical Center Emergency Department (YRMC ED) from 2005 to 2008. A seizure diagnosis was present in 2.7% of the patients, and accounted for 1.7% of all ED visits. Visits by patients identified as having epilepsy accounted for 0.3% of all ED visits. Patients with seizures were 2.8 times more likely to have used the ED for 2 or more years of the study period compared with control patients. Patients with at least one ED visit because of seizures were more likely to have multiyear visits, 43.6% visiting the ED within 2 or more years. Patients with epilepsy and seizures were significantly younger than the no-seizure control group. Patients who had ever been admitted to the ED for seizures or epilepsy had higher ED utilization even if the subsequent admissions were not seizure related.

Relationships among self-management, patient perceptions of care, and health economic outcomes for decision-making and clinical practice in type 2 diabetes

OBJECTIVES

Type 2 diabetes (T2D) treatment involves complex interactions between biological, psychological, and behavioral factors of care, requiring multifaceted efforts in clinical practice and disease management to reduce health and economic burdens. We aimed to quantify correlations among these factors and characterize their level of inclusion in economic analyses that are part of informed medical decision-making.

METHODS

A comprehensive, stepwise systematic literature review was performed on published articles dated 1993 to 2008 using medical subject heading and keyword searches in electronic reference libraries. Data were collected using standardized techniques and were analyzed descriptively.

RESULTS

A total of 97 articles fulfilling all inclusion criteria were reviewed, including 16 on economic models (17% of articles). Most studies were retrospective (41 of 97; 42%) and from managed care perspectives (66%). Oral antidiabetic drugs were a central focus, appearing in 83% of studies. Patient behaviors, particularly medication adherence and persistence in real-world settings, are well researched (n=65) and may influence diabetes outcomes, cardiovascular risk, mortality rates, and treatment-specific resource use (e.g., hospitalizations) and costs (<or=$3400 annually per patient). Nevertheless, they are absent from current economic models.

CONCLUSIONS

Strong correlations exist between patient behaviors, perspectives of care, health outcomes, and costs in T2D. Enhancing their inclusion in pharmacoeconomic modeling, notably the influence on clinical effectiveness of variation in self-management between treatments, should ultimately lead to more accurate estimates of comparative cost-effectiveness, and thereby improve value-based resource allocation and patient access to appropriate therapy.

Costs of medication nonadherence in patients with diabetes mellitus: a systematic review and critical analysis of the literature

OBJECTIVES

Information on the health care costs associated with nonadherence to treatments for diabetes is both limited and inconsistent. We reviewed and critically appraised the literature to identify the main methodological issues that might explain differences among reports in the relationship of nonadherence and costs in patients with diabetes.

METHODS

Two investigators reviewed Medline, EMBASE, Cochrane library and CINAHL and studies with information on costs by level of adherence in patients with diabetes published between January 1, 1997 and September 30th 2007 were included.

RESULTS

A total of 209 studies were identified and ten fulfilled the inclusion criteria. All included studies analyzed claims data and 70% were based on non-Medicaid and non-Medicare databases. Low medication possession ratios were associated with higher costs. Important differences were found in the ICD-9/ICD-9 CM codes used to identify patients and their diagnoses, data sources, analytic window period, definitions of adherence measures, skewness in cost data and associated statistical issues, adjustment of costs for inflation, adjustment for confounders, clinical outcomes and costs.

CONCLUSIONS

Important variation among cost estimates was evident, even within studies of the same population. Readers should be cautious when comparing estimated coefficients from various studies because methodological issues might explain differences in the results of costs of nonadherence in diabetes. This is particularly important when estimates are used as inputs to pharmacoeconomic models.

Impact of nonadherence to antiepileptic drugs on health care utilization and costs: findings from the RANSOM study

PURPOSE

To study the impact of nonadherence to antiepileptic drugs (AEDs) on health care utilization and direct medical costs in a Medicaid population.

METHODS

A retrospective cohort design was employed using state Medicaid claims data from Florida, Iowa, and New Jersey during the period from January 1997 to June 2006. Patients aged >or=18 years with one or more neurologist visit with an epilepsy diagnosis and two or more pharmacy claims for AEDs were included. Medication possession ratio (MPR) was used to evaluate AED adherence with MPR >or= 0.80 considered adherent and <0.80 considered nonadherent. The association of nonadherence with utilization outcomes [hospitalizations, inpatient days, emergency department (ED), and outpatient visits] was assessed with univariate and multivariate Poisson regressions. Quarterly per-patient inpatient, outpatient, ED, and pharmacy costs were calculated across nonadherent and adherent quarters for the younger than 65 population (under-65) and cost differences were computed. Adjusted incremental costs of nonadherence were estimated with multivariate Tobit regression models.

RESULTS

A total of 33,658 patients were included (28,470 under-65), together contributing 388,564 treated quarters (26% nonadherent). In multivariate analyses, AED nonadherence was associated with significantly higher incidence of hospitalizations [incident rate ratio (IRR) = 1.39, 95% confidence interval (CI) = 1.37-1.41], inpatient days (IRR = 1.76, 95% CI = 1.75-1.78), and ED visits (IRR = 1.19, 95% CI = 1.18-1.21). Nonadherence was associated with cost increases related to serious outcomes, including inpatient ($4,320 additional cost per quarter, 95% CI = $4,077-$4,564) and ED services ($303 additional cost per quarter, 95% CI = $273-$334), but lower costs for outpatient and pharmacy services, likely because of nonadherent behavior.

DISCUSSION

Nonadherence to AEDs appears to be associated with serious outcomes, as evidenced by increased utilization and costs of inpatient and ED services.

The association of adherence to antiretroviral therapy with healthcare utilization and costs for medical care

BACKGROUND

The association between antiretroviral adherence, healthcare utilization and medical costs has not been well studied.

OBJECTIVE

To examine the relationship of adherence to antiretroviral medications to healthcare utilization and healthcare costs.

METHODS

A retrospective cohort study was conducted using data from 325 previously antiretroviral medication-naive HIV-infected individuals initiating first antiretroviral therapy from 1997 through 2003. The setting was an inner-city safety net hospital and HIV clinic in the US. Adherence was assessed using pharmacy refill data. The average wholesale price was used for prescription costs. Healthcare utilization data and medical costs were obtained from the hospital billing database, and differences according to quartile of adherence were compared using analysis of variance (ANOVA). Multivariate logistic regression was used to assess predictors of higher annual medical costs. Sensitivity analyses were used to examine alternative antiretroviral pricing schemes. The perspective was that of the healthcare provider, and costs were in year 2005 values.

RESULTS

In 325 patients followed for a mean (+/- SD) 3.2 (1.9) years, better adherence was associated with lower healthcare utilization but higher total medical costs. Annual non-antiretroviral medical costs were $US 7,612 in the highest adherence quartile versus $US 10,190 in the lowest adherence quartile. However, antiretroviral costs were significantly higher in the highest adherence quartile ($US 17,513 vs $US 8,690), and therefore the total annual medical costs were also significantly higher in the highest versus lowest adherence quartile ($US 25,125 vs $US 18,880). In multivariate analysis, for every 10% increase in adherence, the odds of having annual medical costs in the highest versus lowest quartile increased by 87% (odds ratio 1.87; 95% CI 1.45, 2.40). In sensitivity analyses, very low antiretroviral prices (as seen in resource-limited settings) inverted this relationship - excellent adherence was cost saving.

CONCLUSION

Better adherence to antiretroviral medication was associated with decreased healthcare utilization and associated costs; however, because of the high cost of antiretroviral therapy, total medical costs were increased. Combination antiretroviral therapy is known to be cost effective; lower antiretroviral costs may make it cost saving as well.