Cheryl P. Lynch

Medication Nonadherence in Diabetes: Longitudinal effects on costs and potential cost savings from improvement

OBJECTIVE To examine the longitudinal effects of medication nonadherence (MNA) on key costs and estimate potential savings from increased adherence using a novel methodology that accounts for shared correlation among cost categories. RESEARCH DESIGN AND METHODS Veterans with type 2 diabetes (740,195) were followed from January 2002 until death, loss to follow-up, or December 2006. A novel multivariate, generalized, linear, mixed modeling approach was used to assess the differential effect of MNA, defined as medication possession ratio (MPR) ≥0.8 on healthcare costs. A sensitivity analysis was performed to assess potential cost savings at different MNA levels using the Consumer Price Index to adjust estimates to 2012 dollar value. RESULTS Mean MPR for the full sample over 5 years was 0.78, with a mean of 0.93 for the adherent group and 0.58 for the MNA group. In fully adjusted models, all annual cost categories increased ∼3% per year (P = 0.001) during the 5-year study time period. MNA was associated with a 37% lower pharmacy cost, 7% lower outpatient cost, and 41% higher inpatient cost. Based on sensitivity analyses, improving adherence in the MNA group would result in annual estimated cost savings ranging from ∼

Longitudinal Effects of Medication Nonadherence on Glycemic Control

661 million (MPR <0.6 vs. ≥0.6) to ∼

Using quantile regression to investigate racial disparities in medication non-adherence

1.16 billion (MPR <1 vs. 1). Maximal incremental annual savings would occur by raising MPR from <0.8 to ≥0.8 (

Medical care expenditures associated with chronic kidney disease in adults with diabetes: United States 2011

204,530,778) among MNA subjects. CONCLUSIONS Aggressive strategies and policies are needed to achieve optimal medication adherence in diabetes. Such approaches may further the so-called “triple aim” of achieving better health, better quality care, and lower cost.

Longitudinal ethnic differences in multiple cardiovascular risk factor control in a cohort of US adults with diabetes

Background: Medication nonadherence is known to worsen glycemic control. Few studies have examined this relationship over several years. Objective: The aim of this study was to examine the longitudinal effect of medication nonadherence on glycemic control among a large cohort of veterans. Methods: Analysis was performed on a cohort of 11 272 veterans with type 2 diabetes followed from April 1994 to May 2006. The primary outcome measures were mean glycosylated hemoglobin A1c (A1C) and proportion in poor control (A1C > 8%) over time. The main predictor was medication nonadherence based on medication possession ratio (MPR). Other covariates included sociodemographics and ICD-9 coded medical and psychiatric comorbidities. Generalized linear mixed models (GLMMs) were used to assess the relationship between MPR and A1C after adjusting for covariates. Results: Mean follow-up was 5.4 years. In the linear mixed model, after adjusting for baseline A1C and other confounding variables, mean A1C decreased by 0.24 (P < 0.001) for each 10% increase in MPR (95% CI = −0.27, −0.21). In the fully adjusted GLMM, each percentage increase in MPR was associated with a 48% lower likelihood of having poor glycemic control (odds ratio = 0.52; 95% CI = 0.4, 0.6). In both continuous and dichotomized A1C analyses, average A1C showed a decreasing trend over the study period (P < 0.001). Conclusions: In patients with type 2 diabetes, glycemic control worsens over time in the presence of medication nonadherence. Future studies need to take into account the complexity of patient- and system-level factors affecting long-term medication adherence to improve diabetes-related outcomes.

Geographic and Racial/Ethnic Variations in Patterns of Multimorbidity Burden in Patients with Type 2 Diabetes

BackgroundMany studies have investigated racial/ethnic disparities in medication non-adherence in patients with type 2 diabetes using common measures such as medication possession ratio (MPR) or gaps between refills. All these measures including MPR are quasi-continuous and bounded and their distribution is usually skewed. Analysis of such measures using traditional regression methods that model mean changes in the dependent variable may fail to provide a full picture about differential patterns in non-adherence between groups.MethodsA retrospective cohort of 11,272 veterans with type 2 diabetes was assembled from Veterans Administration datasets from April 1996 to May 2006. The main outcome measure was MPR with quantile cutoffs Q1-Q4 taking values of 0.4, 0.6, 0.8 and 0.9. Quantile-regression (QReg) was used to model the association between MPR and race/ethnicity after adjusting for covariates. Comparison was made with commonly used ordinary-least-squares (OLS) and generalized linear mixed models (GLMM).ResultsQuantile-regression showed that Non-Hispanic-Black (NHB) had statistically significantly lower MPR compared to Non-Hispanic-White (NHW) holding all other variables constant across all quantiles with estimates and p-values given as -3.4% (p = 0.11), -5.4% (p = 0.01), -3.1% (p = 0.001), and -2.00% (p = 0.001) for Q1 to Q4, respectively. Other racial/ethnic groups had lower adherence than NHW only in the lowest quantile (Q1) of about -6.3% (p = 0.003). In contrast, OLS and GLMM only showed differences in mean MPR between NHB and NHW while the mean MPR difference between other racial groups and NHW was not significant.ConclusionQuantile regression is recommended for analysis of data that are heterogeneous such that the tails and the central location of the conditional distributions vary differently with the covariates. QReg provides a comprehensive view of the relationships between independent and dependent variables (i.e. not just centrally but also in the tails of the conditional distribution of the dependent variable). Indeed, without performing QReg at different quantiles, an investigator would have no way of assessing whether a difference in these relationships might exist.

Association between spirituality and depression in adults with type 2 diabetes.

OBJECTIVE Approximately 1 in 3 adults with diabetes have CKD. However, there are no recent national estimates of the association of CKD with medical care expenditures in individuals with diabetes. Our aim is to assess the association of CKD with total medical expenditures in US adults with diabetes using a national sample and novel cost estimation methodology. RESEARCH DESIGN AND METHODS Data on 2,053 adults with diabetes in the 2011 Medical Expenditure Panel Survey (MEPS) was analyzed. Individuals with CKD were identified based on self-report. Adjusted mean health services expenditures per person in 2011 were estimated using a two-part model after adjusting for demographic and clinical covariates. RESULTS Of the 2,053 individuals with diabetes, approximately 9.7% had self-reported CKD. Unadjusted mean expenditures for individuals with CKD were

Effect of Trajectories of Glycemic Control on Mortality in Type 2 Diabetes: A Semiparametric Joint Modeling Approach

20,726 relative to

Impact of diabetes control on mortality by race in a national cohort of veterans

9,689.49 for no CKD. Adjusted mean expenditures from the 2-part model for individuals with CKD were

Effect of Perceived Control on Quality of Life in Indigent Adults With Type 2 Diabetes

8473 higher relative to individuals without CKD. Additional significant covariates were Hispanic/other race, uninsured, urban dwellers, CVD, stroke, high cholesterol, arthritis, and asthma. The estimated unadjusted total expenditures for individuals with CKD were estimated to be in excess of