LITERATURE REVIEW

1.Cost Sharing and Decreased Branded Oral Anti-Diabetic Medication Adherence Among
Elderly Part D Medicare Beneficiaries

The article "Cost Sharing and Decreased Branded Oral Anti-Diabetic Medication Adherence
Among Elderly Part D Medicare Beneficiaries" by Naomi C. Sacks and colleagues (2013)
examines how cost-sharing affects the adherence to oral anti-diabetic (OAD) medications
among elderly Medicare Part D beneficiaries. The authors specifically look at the impact of the
Medicare Part D coverage gap and other cost-related factors on the adherence to both generic
and branded OADs.

Using a retrospective cohort design, the study analyzes prescription data from both low-income
subsidy (LIS) and non-LIS beneficiaries. The findings indicate that non-LIS beneficiaries, who
face higher out-of-pocket expenses, show lower adherence rates to more expensive branded
medications like DPP-4 inhibitors and Thiazolidinediones (TZDs) compared to their LIS
counterparts. In contrast, adherence to generic drugs, such as Biguanides and
Sulfonylureas/Glinides, was not significantly affected by cost-sharing mechanisms. The study
suggests that the lower price of generic drugs helps to minimize the impact of cost-related
nonadherence (CRN), which is more evident with branded medications.

The authors propose that eliminating the Medicare Part D coverage gap, a change set to be
completed by 2020, may reduce CRN for branded OADs but will likely have little effect on
adherence to generic medications, which are already affordable. The paper advocates for policy
reforms to alleviate cost barriers, especially for patients with complex health needs who depend
on branded medications, and calls for further investigation into non-cost factors that influence
adherence to generic medications.

This research contributes to the understanding of how medication costs affect adherence,
particularly among elderly individuals with chronic illnesses like diabetes, and highlights the
need for healthcare policies that address financial obstacles to treatment.

2. Impact of Out-of-Pocket Pharmacy Costs on Branded Medication Adherence Among

The study "Impact of Out-of-Pocket Pharmacy Costs on Branded Medication Adherence Among
Patients with Type 2 Diabetes," conducted by Wendy S. Bibeau and colleagues, investigates
how out-of-pocket (OOP) expenses affect adherence to antihyperglycemic medications in
individuals with type 2 diabetes mellitus (T2DM). Utilizing data from the IMS Health Medical
Claims database, the research aims to determine the specific cost level at which adherence to
medications significantly decreases. The authors emphasize the critical role of medication
adherence in diabetes management and note that higher OOP costs are associated with
reduced adherence, which can lead to poorer health outcomes and increased healthcare
expenditures.
The study examined 15,416 patients, categorizing them into four groups based on their
likelihood of incurring high OOP costs. These patients were further divided into five OOP cost
categories, ranging from $0-$10 to more than $75. Through multivariate regression models, the
researchers found that adherence dropped significantly when OOP costs reached the $51-$75
range, with even more substantial declines for costs exceeding $75. Sensitivity analyses
revealed that total OOP costs between $91 and $150 similarly impacted adherence negatively.

This research sheds light on the relationship between cost-sharing and medication adherence,
pinpointing a cost threshold beyond which financial pressures hinder effective diabetes
management. The findings suggest that healthcare plans with high copayments may
unintentionally reduce adherence, contributing to worse health outcomes and higher overall
healthcare costs. The authors recommend that healthcare plans be structured to minimize
financial barriers, helping patients maintain proper medication adherence.

3.Older Adults: Standards of Care in Diabetes—2024

The guidelines stress the need for a comprehensive evaluation that covers medical,
psychological, functional, and social aspects to customize treatment plans for the elderly
population. With more than 25% of individuals over 65 diagnosed with diabetes and many
others with prediabetes, the prevalence of the condition in this age group is rising quickly. Given
the diversity of older adults with both type 1 and type 2 diabetes, individualized care is essential.

Key recommendations include regular screening for geriatric conditions such as cognitive
decline, depression, and frailty, which can affect a patient's ability to manage their diabetes.
Cognitive decline, in particular, poses a significant challenge for older adults, increasing the risk
of hypoglycemia and complications. The guidelines suggest annual cognitive assessments and
modifying care plans to reflect the individual’s cognitive and functional capabilities.

The American Diabetes Association (ADA) prioritizes reducing hypoglycemia through the use of
continuous glucose monitoring (CGM) and advanced insulin delivery systems for both type 1
and type 2 diabetes patients. These technologies have been shown to reduce hypoglycemic
episodes and improve glucose control in older adults by increasing the time spent within target
glucose ranges.

Treatment goals vary depending on the health status of older adults: those in good health
should aim for tighter glycemic control (A1C <7.0–7.5%), while those with more complicated
health issues or limited life expectancy should target a less strict A1C of <8.0% to reduce the
risks associated with intensive treatment.

The article also emphasizes the need for personalized medication management, favoring drugs
with a low risk of hypoglycemia and recommending treatment de-escalation when appropriate in
older adults. It also highlights the importance of lifestyle interventions, including proper nutrition
and physical activity, in enhancing the quality of life for older adults with diabetes.
4.Pharmacologic Approaches to Glycemic Treatment: Standards of Care in
Diabetes—2024

The American Diabetes Association's (ADA) 2024 Standards of Care in Diabetes outlines
detailed guidelines for managing glycemic treatment in adults with both type 1 and type 2
diabetes. For type 1 diabetes, insulin therapy remains essential, with recommendations favoring
continuous subcutaneous insulin infusion (CSII) or multiple daily injections of basal and prandial
insulin. Insulin analogs, particularly rapid-acting and long-acting basal analogs, are
recommended over human insulin to reduce the risk of hypoglycemia.

for type 1 diabetes, the management include Automated Insulin Delivery (AID) systems and
continuous glucose monitoring (CGM) improve glycemic control, quality of life, and reduce
hypoglycemia.
Prandial insulin should be dosed based on carbohydrate intake, with consideration for fat,
protein, concurrent blood glucose levels, and physical activity.
Glucagon is important for treating hypoglycemia, and family members should be trained in its
use.
For type 2 diabetes, the ADA recommends a personalized approach, selecting pharmacologic
treatments based on comorbidities, weight management, and glycemic control needs. The
guidelines stress early initiation of combination therapies, such as GLP-1 receptor agonists and
SGLT2 inhibitors, particularly for individuals with cardiovascular or kidney conditions.
For type 2 diabetes the management include Early combination therapy is advised to achieve
and sustain glycemic control more effectively.
For patients at high cardiovascular or kidney risk, SGLT2 inhibitors and GLP-1 receptor agonists
are recommended for both glucose control and organ protection.
Insulin therapy should be considered for individuals with severe hyperglycemia or catabolic
symptoms, with basal insulin dosing guidelines based on body weight.
The ADA/EASD consensus emphasizes a tailored approach to hyperglycemia management in
type 2 diabetes, the importance of addressing clinical inertia, and assessing the patient’s ability
to afford and access medications.

5.Determinants of Adherence to Diabetes Medications: Findings from a Large Pharmacy

This paper is based on an analysis of data obtained from the information warehouse of a U.S.
based large pharmacy company. The information warehouse includes information like
demographic, eligibility, pharmacy claims information, etc (Kirkman, et al., 2015). A dataset of a
cohort of more than 200,000 patients taking noninsulin diabetes medication was used for logistic
regression analysis. Three predictor variables were defined prior to the analysis, i.e. patient
factors including age; sex; education; etc., prescription factors including refill channel; total pill
burden per day; etc., and prescriber factors including age; sex and speciality (Kirkman, et al.,
2015). Medication possession ratio (MPR) is the proportion “the proportion of days a patient had
a supply of medication during a calendar year or equivalent period” (Kirkman, et al., 2015).
Patients with 0.8 MPR or higher were considered to be adherent with the implication that they
had their medication for at least 80% of the days (Kirkman, et al., 2015). All three predictor
variables patient, prescription, and prescriber factors happened to influence adherence levels.
Patient Factors
Previous studies have indicated that demographic variables significantly impact medication
adherence among diabetes patients. For instance, it has been found that individuals new to
diabetes therapy are 61% less likely to adhere to their medication regimens compared to those
who are continuing therapy (Kirkman, et al., 2015). Age also plays a crucial role: patients aged
25–44 years show a 49% lower adherence rate than those aged 45–64 years, while older
patients (aged 65 and above) demonstrate increased adherence (27% to 41% more likely)
relative to the same age group (Kirkman, et al., 2015).
Men tend to adhere to their medication regimens more than women (Kirkman, et al., 2015),
highlighting the gender difference. Education and income levels also correlate with adherence
rates, where individuals with higher educational attainment (especially those who completed
graduate school) and income (>$60,000) are more likely to be adherent compared to their
less-educated and lower-income counterparts (Kirkman, et al., 2015).
Prescription Factors
Research indicates that patients using mail order channels for their diabetes medications are
more than twice as likely to adhere to their medication compared to those using retail
pharmacies (Kirkman, et al., 2015). This highlights that the mode of prescription delivery
significantly affects medication adherence and corroborates with previous studies suggesting
that streamlined access to medications improves adherence rates. Additionally, an interesting
relationship exists between the total daily pill burden and adherence; for each additional pill a
patient takes, the likelihood of adherence increases by 22% (Kirkman, et al., 2015). Conversely,
higher out-of-pocket costs negatively impact adherence, with a reported decrease in adherence
by 11% for every additional $15 in costs (Kirkman, et al., 2015).

Prescriber Factors
Prescriber factors were found to be less frequently associated with adherence. Patients under
the care of endocrinologists exhibit no higher odds of adherence compared to those receiving
care from primary care physicians (Kirkman, et al., 2015). However, patients with
non-endocrinologist specialist prescribers show slightly lower adherence rates (Kirkman, et al.,
2015). Furthermore, prescriber age has a marginal effect, with adherence increasing by 0.2%
for each additional year of age (Kirkman, et al., 2015).

Factors such as age, gender, education, income, prescription delivery method, and prescriber
characteristics play significant roles. The findings from this research highlight the importance of
addressing both patient and prescription factors to improve adherence rates.

6.The impact of prescription medication cost coverage on optimal adherence to

The study by Razan analyzed data from the Canadian Community Health Survey across four
cycles (2007, 2008, 2013, and 2014), focusing on individuals from Ontario and New Brunswick
that had “either hypertension or diabetes and answered questions on both coverage and
adherence to medications” (Amoud, 2018). A multivariate-adjusted logistic regression model
was fitted to the data to estimate the odds of non-adherence depending on coverage (Amoud,
2018). It found that individuals without prescription coverage were 23% less likely to adhere to
their prescribed oral diabetes and hypertension medications (Amoud, 2018) . Subgroup analysis
revealed that younger patients (aged less than 65 years), middle-income earners, and Ontario
residents without coverage exhibited particularly low adherence (Amoud, 2018).
In conclusion, there is a direct relationship between absence of prescription medication
coverage and reduced adherence to diabetes and hypertension oral medications (Amoud,
2018). Providing prescription cost coverage could improve adherence and health outcomes for
chronic disease patients.

7.The Impact of Prescription Medication Cost Coverage on Oral Medication Use for
Hypertension and Type 2 Diabetes Mellitus

According to Polonsky and Henry (2016), one of the critical determinants for the management of
hypertension and Type 2 Diabetes Mellitus is the cost coverage of prescription medication. Most
patients with these conditions face a lifetime need for the continuous intake of medications to
prevent complications and manage symptoms effectively. The costs of such essential medicines
make it difficult for many persons to continue taking their prescribed medications. The literature
reviews provide an oversight of the relationship between medication cost coverage and
adherence to hypertension and Type 2 Diabetes Mellitus diagnosis. Zheng et al. (2018) state
that hypertension and Type 2 Diabetes Mellitus are common chronic disorders that involve
significant health burdens worldwide. Management for either involves oral medication on a
long-term basis, which is often very expensive for many patients, and others cannot afford their
medications. Piette et al. (2004) studied cost-related medication underuse and noted that a high
medication cost was associated with skipping doses or not filling prescriptions altogether. In
chronic illnesses, such as hypertension and diabetes, this cost-related nonadherence was
generally familiar.
Significantly, health insurance that reduced or eliminated out-of-pocket costs greatly facilitated
medication adherence. Karter et al. (2010) point out that among diabetic patients, adherence to
oral hypoglycemic medication therapy was considerably more regular for the ones having
comprehensive prescription drug coverage compared with those who have limited and no
coverage. Karter et al.'s (2010) study demonstrates how financial assistance is vital in ensuring
patients comply with their prescribed medication schedules to attain desired health outcomes.
However, prescription drug coverage for seniors in the United States was widely studied
regarding medication adherence with the inception of Medicare Part D. Zhang et al. (2009)
found that Medicare Part D beneficiaries showed better adherence to diabetes and hypertension
medications than their pre-Part D use. It underlined the positive effects of reduced financial
barriers on medication adherence and overall health outcomes. By lessening some of the cost
burden associated with it, Medicare Part D has succeeded in helping more patients remain
compliant with their prescribed treatments against these chronic conditions.
Despite the advances, disparities in medication adherence persist, especially among people
with low incomes. Heisler et al. (2005) state that low-income patients encountered substantial
barriers to medication adherence even with partial prescription coverage due to costs remaining
after insurance coverage. This study called attention to the need for more broad-based solutions
that consider the financial constraints of low-income patients. Small copayments present
formidable barriers to these groups, and comprehensive and inclusive coverage policy
packages are needed for optimal adherence. Besides, this relationship is not just about
prescription and the nature of medication cost coverage but also its influence on adherence. For
instance, Ngoh (2009) argues that patient education, health literacy, and provider support are
integral to improving adherence as they interact with financial assistance. Interventions that
comprehensively address these factors tend to work more effectively. For example, patient
education programs will enhance patient knowledge regarding the rationale for and importance
of adherence and produce better health outcomes when combined with financial assistance.
Brown and Bussell's (2011) study concludes that support from a healthcare provider is
paramount to increasing the patient's medication adherence. The provider influences may also
focus on education about adherence benefits and consequences of nonadherence. Providers
can also facilitate financial assistance programs and insurance benefits, resulting in easy
medication access. Healthcare providers can support their patients through applications of
medication assistance programs or offer generic alternatives that are affordable for the clients

REFERENCES

1. Sacks et al.Cost sharing and decreased branded oral anti-diabetic medication adherence
among elderly Part D Medicare beneficiaries. 2013 Jul; 28(7): 876–885

2. Bibeau et al. Impact of Out-of-Pocket Pharmacy Costs on Branded Medication Adherence

3. Older Adults: Standards of Care in Diabetes—2024.

4. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes—2024 |

5. Kirkman, M. S., Rowan-Martin, M. T., Levin, R., Fonseca, V. A., Schmittdiel, J. A., Herman, W.
H., & Aubert, R. E. (2015, January 8). Determinants of Adherence to Diabetes Medications:
Findings From a Large Pharmacy Claims Databases

6. Amoud, R. (2018, February 26). The impact of prescription medication cost coverage on
optimal adherence to Hypertension and Diabetes Mellitus oral medications