Geospatial analysis of statin adherence using pharmacy claims data in the state of Michigan

Geosocial Factors Associated With Adherence to Statin Medications

Background:

Individual patient characteristics, social determinants, and geographic access may be associated with patients engaging in appropriate health behaviors.

Objective:

To assess the relationship between statin adherence, geographic accessibility to pharmacies, and neighborhood sociodemographic characteristics in Michigan.

Methods:

The proportion of days covered (PDC) was calculated from pharmacy claims of a large insurer of adults who had prescriptions for statins between July 2009 and June 2010. A PDC ≥0.80 was defined as adherent. The predictor of interest was a ZIP code tabulation area (ZCTA)-level measure of geographic accessibility to pharmacies, measured using a method that integrates availability and access into a single index. We fit unadjusted models as well as adjusted models controlling for age, sex, and ZCTA-level measures of socioeconomic status (SES), racial isolation (RI) of non-Hispanic blacks, and urbanicity.

Results:

More than 174 000 patients’ claims data were analyzed. In adjusted models, pharmacy access was not associated with adherence (0.99; 95% CI: 0.96, 1.03). Greater RI (0.87; 95% CI: 0.85, 0.88) and urban status (0.93; 95% CI: 0.89, 0.96) were associated with lower odds of adherence. Individuals in ZCTAs with higher SES had higher odds of adherence, as were men and older age groups.

Conclusion and Relevance:

Adherence to statin prescriptions was lower for patients living in areas characterized as being racially segregated or lower income. Initiating interventions to enhance adherence, informed by understanding the social and systematic barriers patients face when refilling medication, is an important public health initiative that pharmacists practicing in these areas may undertake.

Use of Low-Density Lipoprotein-Lowering Therapies Before and After PCSK9 Inhibitor Initiation

Background Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are used to reduce low-density lipoprotein (LDL) cholesterol. PCSK9i use after initiation, as well as persistence with or alterations to other LDL-lowering therapy after PCSK9i initiation, is not well understood. Methods and Results We conducted a retrospective study of alirocumab or evolocumab (PCSK9i) new users from July 2015 to December 2017 in the MarketScan Early View database of US commercial insurance beneficiaries. We determined the prevalence of PCSK9i interruption (≥30-day gap in supply) and LDL-lowering therapy use in the year after PCSK9i initiation. The average age of 6151 patients initiating PCSK9i therapy was 63 years, 44.4% were women, and 76.8% had atherosclerotic cardiovascular disease. Overall, 52.2% (95% CI, 50.8%-53.7%) of patients had an interruption in PCSK9i therapy in the first year after treatment initiation and 62.5% remained on PCSK9i therapy at 1-year postinitiation. Also, 27.7% of patients were taking a statin at the time of PCSK9i initiation, with only 22.4% on statin therapy at 1 year after PCSK9i initiation. Ezetimibe use decreased from 20.9% at the time of PCSK9i initiation to 12.0% a year later. By 1 year after PCSK9i initiation, 44.0% of patients had experienced an interruption in all LDL-lowering therapies, and 26.6% were no longer on any LDL-lowering therapies. Conclusions After PCSK9i initiation, statins were often discontinued, whereas more than half of patients experienced an interruption in PCSK9i therapy. These results suggest that many new PCSK9i users may remain at high risk for cardiovascular events because of interruptions in LDL-lowering therapy.

Interrupted time series analysis on first cardiovascular disease hospitalization for adherence to lipid-lowering therapy

PURPOSE

We analysed lipid-lowering medication adherence before and after the first hospitalization for cardiovascular disease (CVD) to explore the influence hospitalization has on patient medication adherence.

METHODS

We extracted a sub-cohort for analysis from 313,207 patients who had primary CVD risk assessment. Adherence was assessed as proportion of days covered (PDC) ≥ 80% based on community dispensing records. Adherence in the 4 quarters (360 days) before the first CVD hospitalization and 8 quarters (720 days) after hospital discharge was assessed for each individual in the sub-cohort. An interrupted time series design using generalized estimating equations was applied to compare the differences of population-level medication adherence rates before and after the first CVD hospitalization.

RESULTS

Overall, a significant improvement in medication adherence rate from before to after the hospitalization was observed (odds ratio (OR) 2.49 [1.74-3.57]) among the 946 patients included in the analysis. Patients having diabetes history had a higher OR of adherence before the hospitalization than patients without diabetes (1.50 [1.03-2.22]) but no significant difference after the hospitalization (OR 1.13 [0.89-1.43]). Before the first hospitalization, we observed that quarterly medication adherence rate was steady at around 55% (OR 0.97 [0.93-1.01), whereas the trend in adherence over the post-hospitalization period decreased significantly per quarter (OR 0.97 [0.94-0.99]).

CONCLUSIONS

Patients were more likely to adhere to lipid-lowering therapy after experiencing a first CVD hospitalization. The change in medication adherence rate is consistent with patients having heightened perception of disease severity following the hospitalization.

Environmental and individual predictors of medication adherence among elderly patients with hypertension and chronic kidney disease: A geospatial approach

BACKGROUND

Few studies have examined how adherence to antihypertensive medications varies across different regions or how neighborhood-level factors were related to individuals' medication-taking behaviors in patients.

OBJECTIVE

To explore local variation in medication adherence and examine environmental and individual influences on adherence to angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) among elderly hypertensive patients with chronic kidney disease (CKD) in the United States.

METHODS

The Medicare 5% sample claim data (2006-2013), American Community Survey 5-Year Data (2005-2009) and the Health Resources and Services Administration Primary Care Service Area data (2007). The primary outcome was medication adherence, measured by Proportion of Days Covered (PDC). Geographically weighted regression (GWR) and linear mixed-effects models were used to investigate the relationship between environmental factors, individual risk factors and medication adherence.

RESULTS

A total of 70,201 hypertensive CKD patients residing in 2,981 counties of the US were selected. Significant spatial autocorrelation was observed in ACEIs/ARBs PDC. The West North Central and New England regions demonstrated higher adherence compared to the East South Central and West South Central regions. Residing in Medically Underserved Areas, counties with high deprivation scores, and not receiving Part D Low-income Subsidy were associated with poor medication adherence.

CONCLUSIONS

Medication adherence is geographically differentiated across the US. Environmental and individual factors identified may be helpful in the design of local interventions focused on improving patient outcomes from a population perspective.

Identifying Spatial Variation Along the HIV Care Continuum: The Role of Distance to Care on Retention and Viral Suppression

Distance to HIV care may be associated with retention in care (RIC) and viral suppression (VS). RIC (≥ 2 HIV visits or labs ≥ 90 days apart in 12 months), prescribed antiretroviral therapy (ART), VS (< 200 copies/mL at last visit) and distance to care were estimated among 3623 DC Cohort participants receiving HIV care in 13 outpatient clinics in Washington, DC in 2015. Logistic regression models and geospatial statistics were computed. RIC was 73%; 97% were on ART, among whom 77% had VS. ZIP code-level clusters of low RIC and high VS were found in Northwest DC, and low VS in Southeast DC. Those traveling ≥ 5 miles had 30% lower RIC (adjusted odds ratio (aOR) 0.71, 95% CI 0.58, 0.86) and lower VS (OR 0.70, 95% CI 0.52, 0.94). Geospatial clustering of RIC and VS was observed, and distance may be a barrier to optimal HIV care outcomes.

Mapping pharmacy deserts and determining accessibility to community pharmacy services for elderly enrolled in a State Pharmaceutical Assistance Program

Objectives

Limited studies have investigated geographic accessibility to a nearby community pharmacy for elderly which is an essential determinant of the access to medications and pharmacy services. This research identified pharmacy deserts and investigated availability of different types of community pharmacies and their services for elderly enrolled in a State Pharmaceutical Assistance Program (SPAP).

Methods

The state of Pennsylvania in the US was used as a case to demonstrate the geographic accessibility to community pharmacy and services for elderly enrolled in SPAP. The locations of community pharmacies and households of elderly enrolled in SPAP were derived from Pharmaceutical Assistance Contract for the Elderly programs’ database. The street addresses were geocoded and the distance to a nearby community pharmacy was calculated for study sample using the haversine formula. The demographic and geographic data were aggregated to Census Tracts and pharmacy deserts were identified using the predefined criteria. Descriptive statistical analysis was used to determine whether there are statistical differences in the socio-demographic profiles and distribution of different types of community pharmacies and their services in pharmacy deserts and non-deserts. This research used hot spot analyses at county level to identify clusters of pharmacy deserts, areas with high concentration of different racial/ethnic groups and clusters of high densities of chain and independent pharmacies.

Results

The Spatial analysis revealed that 39% and 61% Census Tracts in Pennsylvania were pharmacy deserts and non-deserts respectively (p < 0.001). Pharmacy deserts were found to have significantly more females, married and white elderly and fewer blacks and Hispanics compared to pharmacy non-deserts. Pharmacy deserts had significantly fewer chain and independent pharmacies and less delivery and 24-hour services in pharmacies than pharmacy non-deserts. Hot spot analyses showed that clusters of pharmacy deserts were more concentrated in southcentral, northwest and northeast regions of the state which represent rural areas and overlapped with clusters of high concentration of white individuals.

Conclusions

The findings suggest that urban-rural inequality, racial/ethnic disparity and differences in availability of pharmacies and their services exist between pharmacy deserts and non-deserts. The methodological approach and analyses used in this study can also be applied to other public health programs to evaluate the coverage and breadth of public health services.

PCSK9 inhibition in the management of hyperlipidemia: focus on evolocumab

Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases low-density lipoprotein cholesterol (LDL-C) concentrations through interference with normal physiologic hepatic LDL receptor (LDLR) recycling. Inhibiting PCSK9 results in improved LDLR recycling, increased LDLR availability on hepatocyte cell surfaces, and reduced blood LDL-C levels, making PCSK9 inhibition a novel therapeutic strategy for managing hypercholesterolemia. Monoclonal antibodies directed against PCSK9 have been developed for this purpose. A large number of clinical trials have demonstrated that monoclonal antibodies against PCSK9 yield substantial reductions in LDL-C when administered as monotherapy or in combination with statins to patients with nonfamilial and familial forms of hypercholesterolemia. Data from long-term trials demonstrate that the LDL-C-lowering effect of PCSK9 inhibitors is durable. These agents are generally well tolerated, and few patients discontinue treatment due to adverse events. Moreover, PCSK9 inhibitors do not appear to elicit the hepatic and muscle-related side effects associated with statin use. The ultimate value of PCSK9 inhibitors will be measured by their effect on clinical outcomes. Early evidence of a reduction in cardiovascular events after 1 year of treatment was shown in a prospective exploratory analysis of two ongoing long-term open-label extension evolocumab trials. Similarly, cardiovascular events were reduced in another exploratory analysis after >1 year of therapy with alirocumab. For the primary care physician, PCSK9 inhibitors represent a welcome additional option for lowering LDL-C in patients with familial forms of hypercholesterolemia and those with clinical atherosclerotic cardiovascular disease who are on maximally tolerated statin therapy.