Sensitivity of the Medication Possession Ratio to Modelling Decisions in Large Claims Databases

Investigating medication adherence among Taiwanese patient with hypertension, hyperlipidemia, and diabetes: A pilot study using the Chinese version of a Two-Part Medication Nonadherence Scale and the NHI MediCloud system

BACKGROUND

This pilot study aimed to investigate medication nonadherence among Taiwanese patients with diabetes, hypertension, and hyperlipidemia using the Chinese version of the Two-Part Medication Nonadherence Scale (C-TPMNS) and the National Health Insurance (NHI) Medicloud system. The study revealed insights into the factors contributing to nonadherence and the implications for improving patient adherence to medications for chronic conditions. However, the small sample size limits the generalizability of the findings. Additionally, the study identified the need for further research with larger and more diverse samples to validate the preliminary findings.

METHODS

The study conducted surveys individuals in central Taiwan who received three-high medications and those who returned expired medications from chain pharmacies. A structured questionnaire including the C-TPMNS was administered, and additional data on medical history and HbA1c, LDL, and blood pressure levels were collected from the NHI Medicloud system. Data analysis was performed using multiple ordered logistic regression and Wald test methods. Setting interpretation cutoff point to determine medication nonadherence.

RESULTS

The study found that 25.8% of participants were non-adherent to prescribed medications. Non-adherent individuals had significantly higher systolic blood pressure (SBP ≥ 140 mmHg) than adherent participants. Non-adherence was also associated with factors such as lower education, single status, living alone, abnormal glucose postprandial concentration, and triglyceride levels. The C-TPMNS demonstrated good reliability (Cronbach's alpha = 0.816) and validity (area under the ROC curve = 0.72).

CONCLUSION

The study highlighted the complexity of medication nonadherence with diverse determinants and emphasized the importance of tailored interventions. The findings underscored the need for region-specific research to comprehensively address medication nonadherence, especially focusing on adherence to medications for hypertension, hyperlipidemia, and diabetes. The study also identified the need for larger, more diverse studies to validate and expand upon the initial findings and emphasized the importance of pharmacist interventions and patient empowerment in managing chronic conditions and improving overall health outcomes.

Methods to assess COPD medications adherence in healthcare databases: a systematic review

BACKGROUND

The Global Initiative for Chronic Obstructive Lung Disease 2023 report recommends medication adherence assessment in COPD as an action item. Healthcare databases provide opportunities for objective assessments; however, multiple methods exist. We aimed to systematically review the literature to describe existing methods to assess adherence in COPD in healthcare databases and to evaluate the reporting of influencing variables.

METHOD

We searched MEDLINE, Web of Science and Embase for peer-reviewed articles evaluating adherence to COPD medication in electronic databases, written in English, published up to 11 October 2022 (PROSPERO identifier CRD42022363449). Two reviewers independently conducted screening for inclusion and performed data extraction. Methods to assess initiation (dispensing of medication after prescribing), implementation (extent of use over a specific time period) and/or persistence (time from initiation to discontinuation) were listed descriptively. Each included study was evaluated for reporting variables with an impact on adherence assessment: inpatient stays, drug substitution, dose switching and early refills.

RESULTS

160 studies were included, of which four assessed initiation, 135 implementation and 45 persistence. Overall, one method was used to measure initiation, 43 methods for implementation and seven methods for persistence. Most of the included implementation studies reported medication possession ratio, proportion of days covered and/or an alteration of these methods. Only 11% of the included studies mentioned the potential impact of the evaluated variables.

CONCLUSION

Variations in adherence assessment methods are common. Attention to transparency, reporting of variables with an impact on adherence assessment and rationale for choosing an adherence cut-off or treatment gap is recommended.

Estimating medication adherence from Electronic Health Records: comparing methods for mining and processing asthma treatment prescriptions

BACKGROUND

Medication adherence is usually defined as the extent of the agreement between the medication regimen agreed to by patients with their healthcare provider and the real-world implementation. Proactive identification of those with poor adherence may be useful to identify those with poor disease control and offers the opportunity for ameliorative action. Adherence can be estimated from Electronic Health Records (EHRs) by comparing medication dispensing records to the prescribed regimen. Several methods have been developed in the literature to infer adherence from EHRs, however there is no clear consensus on what should be considered the gold standard in each use case. Our objectives were to critically evaluate different measures of medication adherence in a large longitudinal Scottish EHR dataset. We used asthma, a chronic condition with high prevalence and high rates of non-adherence, as a case study.

METHODS

Over 1.6 million asthma controllers were prescribed for our cohort of 91,334 individuals, between January 2009 and March 2017. Eight adherence measures were calculated, and different approaches to estimating the amount of medication supply available at any time were compared.

RESULTS

Estimates from different measures of adherence varied substantially. Three of the main drivers of the differences between adherence measures were the expected duration (if taken as in accordance with the dose directions), whether there was overlapping supply between prescriptions, and whether treatment had been discontinued. However, there are also wider, study-related, factors which are crucial to consider when comparing the adherence measures.

CONCLUSIONS

We evaluated the limitations of various medication adherence measures, and highlight key considerations about the underlying data, condition, and population to guide researchers choose appropriate adherence measures. This guidance will enable researchers to make more informed decisions about the methodology they employ, ensuring that adherence is captured in the most meaningful way for their particular application needs.

A comparison of methods for the measurement of adherence to antihypertensive multidrug therapy and the clinical consequences: a retrospective cohort study using the Korean nationwide claims database

OBJECTIVES

In observational studies, the methods used to measure medication adherence may affect assessments of the clinical outcomes of drug therapy. This study estimated medication adherence to multidrug therapy in patients with hypertension using different measurement methods and compared their impacts on clinical outcomes.

METHODS

This was a retrospective cohort study using the Korean National Health Insurance Service-National Sample Cohort database (2006-2015). Adults diagnosed with hypertension who initiated multidrug antihypertensive therapy in the index year 2007 were included. Adherence was defined as over 80% compliance. Adherence to multidrug antihypertensive therapy was measured in 3 ways using the proportion of days covered (PDC) with 2 approaches to the end-date of the study observations: PDC with at least one drug (PDCwith≥1), PDC with a duration weighted mean (PDCwm), and the daily polypharmacy possession ratio (DPPR). The primary clinical outcome was a composite of cardiovascular and cerebrovascular disease-specific hospitalizations or all-cause mortality.

RESULTS

In total, 4,226 patients who initiated multidrug therapy for hypertension were identified. The mean adherence according to the predefined measurements varied from 72.7% to 79.8%. Non-adherence was associated with an increased risk of a primary outcome. The hazard ratios (95% confidence intervals, CIs) primary outcomes varied from 1.38 (95% CI, 1.19 to 1.59) to 1.44 (95% CI, 1.25 to 1.67).

CONCLUSIONS

Non-adherence to multidrug antihypertensive therapy was significantly associated with an increased risk of a primary clinical outcome. Across the varying estimates based on different methods, medication adherence levels were similar. These findings may provide evidence to support decision-making when assessing medication adherence.

Laboratory testing and antihypertensive medication adherence following initial treatment of incident, uncomplicated hypertension: A real-world data analysis

In this study on medication adherence among newly diagnosed patients with uncomplicated, incident hypertension, we conducted a retrospective cohort study using available administrative and laboratory data from April 1, 2012 to March 31, 2017 in Alberta, Canada to understand the extent to which baseline laboratory assessment and/or subsequent follow-up was associated with persistence with antihypertensive therapy. We determined the frequency of baseline and follow-up testing and compared the rates of medication persistence by patient-, neighbourhood-, and treatment-related factors. Of 103 232 patients with newly diagnosed, uncomplicated hypertension who filled their first prescription within our study timeframe, 52.5% were non-persistent within 6 months. Persistent patients were more often female and residing in neighbourhoods with higher social status (with exception to rurality). Aside from older age, the strongest predictor of persistence was performance of laboratory testing related to hypertension with an apparent effect in which higher levels of medication persistence were seen with more frequent laboratory testing. We concluded that medication persistence was far from optimal, dropping off considerably after 6 months for more than half of patients. Medication persistence is a substantial barrier to realizing the full societal benefits of antihypertensive treatment. Ongoing follow up with patients, including laboratory testing, may be a critical component of better long term treatment persistence.

A systematic review and meta-analysis on impact of suboptimal use of antidepressants, bisphosphonates, and statins on healthcare resource utilisation and healthcare cost

BACKGROUND

Depression, osteoporosis, and cardiovascular disease impose a heavy economic burden on society. Understanding economic impacts of suboptimal use of medication due to nonadherence and non-persistence (non-MAP) for these conditions is important for clinical practice and health policy-making.

OBJECTIVE

This systematic literature review aims to assess the impact of non-MAP to antidepressants, bisphosphonates and statins on healthcare resource utilisation and healthcare cost (HRUHC), and to assess how these impacts differ across medication classes.

METHODS

A systematic literature review and an aggregate meta-analysis were performed. Using the search protocol developed, PubMed, Cochrane Library, ClinicalTrials.gov, JSTOR and EconLit were searched for articles that explored the relationship between non-MAP and HRUHC (i.e., use of hospital, visit to healthcare service providers other than hospital, and healthcare cost components including medical cost and pharmacy cost) published from November 2004 to April 2021. Inverse-variance meta-analysis was used to assess the relationship between non-MAP and HRUHC when reported for at least two different populations.

RESULTS

Screening 1,123 articles left 10, seven and 13 articles on antidepressants, bisphosphonates, and statins, respectively. Of those, 27 were rated of good quality, three fair and none poor using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. In general, non-MAP was positively associated with HRUHC for all three medication classes and most prominently for bisphosphonates, although the relationships differed across HRUHC components and medication classes. The meta-analysis found that non-MAP was associated with increased hospital cost (26%, p = 0.02), outpatient cost (10%, p = 0.01), and total medical cost excluding pharmacy cost (12%, p<0.00001) for antidepressants, and increased total healthcare cost (3%, p = 0.07) for bisphosphonates.

CONCLUSIONS

This systematic literature review is the first to compare the impact of non-MAP on HRUHC across medications for three prevalent conditions, depression, osteoporosis and cardiovascular disease. Positive relationships between non-MAP and HRUHC highlight inefficiencies within the healthcare system related to non-MAP, suggesting a need to reduce non-MAP in a cost-effective way.

Comparison of Approaches for Measuring Adherence and Persistence to Oral Oncologic Therapies in Patients Diagnosed with Metastatic Renal Cell Carcinoma

BACKGROUND

Adherence and persistence studies face several methodologic difficulties, including short-term mortality. We compared approaches to quantify adherence and persistence to first line (1L) oral targeted therapy (TT) in patients diagnosed with metastatic renal cell carcinoma (mRCC).

METHODS

Patients with mRCC ages 66 years or more who initiated TTs within 4 months of diagnosis were identified in the Surveillance, Epidemiology, and End Results Medicare-linked database (2007-2015). Adherence [proportion of days covered (PDC) >80%] was calculated using (i) PDC with a fixed 6-month denominator including then excluding patients who died within the 6 months and (ii) PDC with a denominator measuring time on treatment. Risk of nonpersistence was obtained by censoring death or treating death as a competing risk using cumulative incidence functions.

RESULTS

Among 485 patients with mRCC initiating a 1L oral TT (sunitinib, 64%; pazopanib, 25%; other, 11%), 40% died within 6 months. Adherence was higher after restricting to patients who survived (60%) compared with including those patients and assigning zero days covered after death (47%). Risk of nonpersistence was higher when censoring patients at death, 0.91 [95% confidence interval (CI), 0.88-0.94], compared with treating death as a competing risk, 0.75 (95% CI, 0.71-0.79).

CONCLUSIONS

Different approaches to handling death resulted in different adherence and persistence estimates in the metastatic setting. Future studies should explicitly report the proportion of patient deaths over time and explore appropriate methods to account for death as competing risk.

IMPACT

Use of several approaches can provide a more comprehensive picture of medication-taking behavior in the metastatic setting where death is a major competing risk.

Protective Effects of Angiotensin Receptor Blockers on the Incidence of Dementia in Patients with Chronic Kidney Disease: A Population-Based Nationwide Study

Chronic kidney disease (CKD) is associated with dementia. Angiotensin receptor blockers (ARBs) have been widely used for delaying CKD progression; however, their effect on dementia prevention in patients with CKD remains unclear. We designed a retrospective cohort study to investigate the effects of ARBs on the incidence of dementia in patients with CKD. We selected 21,208 patients from the Taiwan nationwide database from 1 January 2006 to 31 December 2006. We identified ARB users (n = 17,466) and ARB non-users (n = 3742) and their medication possession ratio (MPR). The Cox proportional hazard model was used to estimate hazard ratios (HRs) for the incidence of dementia in ARB users in the CKD population. During the 11-year follow-up period, 2207 dementia events were recorded; multivariate-adjusted hazard ratios for dementia by ARB usage and ARB usage per MPR were 0.578 (95% CI: 0.52-0.643) and 0.996 (95% CI: 0.995-0.998), respectively. This association was observed in almost all subgroups. Dose frequency effect of ARBs was noted; patients with higher MPRs of ARBs generally had higher protection from dementia. Patients with hypertension and CKD who received ARBs had a decreased risk of dementia. Protective effects of ARBs on dementia increased with the frequency of ARB use.

Self-reported vs. objectively assessed adherence to inhaled corticosteroids in asthma

BACKGROUND

Adherence to inhaled corticosteroids (ICS) in asthma is vital for disease control. However, obtaining reliable and clinically useful measures of adherence remains a major challenge. We investigated the association between patient-reported adherence and objectively measured adherence based on filled prescriptions with inhaled corticosteroids in adults with asthma.

METHODS

In total, 178 patients with asthma were asked to self-assess adherence during routine visits at a respiratory outpatient clinic. Self-assessment was performed using Foster score ("How many days in a 7-day week do you take your medication as prescribed?", with the answer divided by 7). Objective adherence was calculated as medication possession ratio (MPR). Bivariate and multivariable linear regression, adjusted for age, sex, FEV1, GINA treatment step, excessive use of SABA, and history of exacerbations were used for analyses.

RESULTS

Of the included patients, 87.6% reported a Foster score of 100%, while the mean ICS MPR was 54.0% (SD 25%). Complex regimens such as twice-daily dosing or dual inhaler-use were associated with lower adherence (p = 0.015 and p < 0.001, respectively). Foster score was predictive of ICS MPR, with an absolute 32% increase in MPR between patients reporting Foster scores of 0 and 100% (95% CI 13-50%, p < 0.001). Female sex predicted higher ICS MPR (p = 0.019). Previous asthma-related hospitalization(s) predicted lower ICS MPR (p = 0.039).

CONCLUSION

Although a weak association was found between Foster score and ICS MPR, findings do not support the use of Foster score, and by that self-reported adherence, as a reliable marker of controller adherence in asthma due to significant mismatch between patient-reported adherence and MPR. Future studies should address the complex interplay between patient-reported and objectively assessed adherence to controller medication in asthma.

Comparing the Predictive Effects of Patient Medication Adherence Indices in Electronic Health Record and Claims-Based Risk Stratification Models

Multiple indices are available to measure medication adherence behaviors. Medication adherence measures, however, have rarely been extracted from electronic health records (EHRs) for population-level risk predictions. This study assessed the value of medication adherence indices in improving predictive models of cost and hospitalization. This study included a 2-year retrospective cohort of patients younger than age 65 years with linked EHR and insurance claims data. Three medication adherence measures were calculated: medication regimen complexity index (MRCI), medication possession ratio (MPR), and prescription fill rate (PFR). The authors examined the effects of adding these measures to 3 predictive models of utilization: a demographics model, a conventional model (Charlson index), and an advanced diagnosis-based model. Models were trained using EHR and claims data. The study population had an overall MRCI, MPR, and PFR of 14.6 ± 17.8, .624 ± .310, and .810 ± .270, respectively. Adding MRCI and MPR to the demographic and the morbidity models using claims data improved forecasting of next-year hospitalization substantially (eg, AUC of the demographic model increased from .605 to .656 using MRCI). Nonetheless, such boosting effects were attenuated for the advanced diagnosis-based models. Although EHR models performed inferior to claims models, adding adherence indices improved EHR model performances at a larger scale (eg, adding MRCI increased AUC by 4.4% for the Charlson model using EHR data compared to 3.8% using claims). This study shows that medication adherence measures can modestly improve EHR- and claims-derived predictive models of cost and hospitalization in non-elderly patients; however, the improvements are minimal for advanced diagnosis-based models.

Comparing the Sensitivities of Measures of Adherence to Antihypertensive Drugs Using Korean National Health Insurance Claims Data

PURPOSE

Numerous studies have utilized various forms of adherence measures. However, methods for measuring adherence are inconsistent. Moreover, few studies are available that have compared sensitivities of the effects of several criteria on medication adherence. This study aims to compare measures of adherence using varied analytical decisions.

MATERIALS AND METHODS

We included three measures for adherence: proportion of days covered with one or more medications (PDC_with≥1), duration weighted mean PDC (PDC_wm), and daily polypharmacy possession ratio (DPPR). We compared the sensitivities of the measures by changing parameters in the Korean nationwide claims database. First, we used PDC_with≥1 as our base model. Then, we divided an adherence measure algorithm into three categories: (1) definition of data cleaning, (2) inclusion criteria and observation period, and (3) calculation methods of medication adherence. The categories included eight decision nodes that incorporated 25 alternative options. Finally, we assessed the medication adherence for the base-case with commonly used values and then varied to measure with each alternative option.

RESULTS

The base-case included 14,288 beneficiaries with antihypertensives. Among eight decisions, both handling an end-date-of-study and overlaps had the strongest impacts on measuring PDC_with≥1, PDC_wm, and DPPR, with small differences in sample size. Instead of the estimates of adherence from PDC_wm, those of PDC_with≥1 and DPPR were similar. Furthermore, a tendency toward a higher medication adherence was observed with a smaller study population.

CONCLUSION

The decisions regarding identifying an end-date-of-study and overlaps showed meaningful impacts of all three measures including PDC_with≥1, PDCwm, and DPPR on measuring medication adherence.

Polypharmacy, Medication Possession, and Deprescribing of Potentially Non-Beneficial Drugs in Hospice Patients

Patients frequently have comorbidities that when combined with their primary diagnosis qualifies the patient for hospice. Consequently, patients are at risk for polypharmacy due to the number of medications prescribed to treat both the underlying conditions and the related symptoms. Polypharmacy is associated with negative consequences, including increased risk for adverse drug events, drug-drug and drug-disease interactions, reduced functional status and falls, multiple geriatric syndromes, medication nonadherence, and increased mortality. Polypharmacy also increases the complexity of medication management for caregivers and contributes to the cost of prescription drugs for hospices and patients. Deprescribing or removing nonbeneficial or ineffective medications can reduce polypharmacy in hospice. We study medication possession ratios and rates of deprescribing of commonly prescribed but potentially nonbeneficial classes of medication using a large hospice pharmacy database. Prevalence of some classes of potentially inappropriate medications is high. We report possession ratios for 10 frequently prescribed classes, and, because death and prescription termination are competing events, we calculate prescription termination rates using Cumulative Incidence Functions. Median duration of antifungal and antiviral medications is brief (5 and 7 days, respectively), while statins and diabetes medications have slow discontinuance rates (median termination durations of 93 and 197 days). Almost all patients with a proton pump inhibitor prescription have the drug for their entire hospice stay. Data from this study identify those drug classes that are commonly deprescribed slowly, suggesting drug classes and diagnoses that hospices may wish to focus on more closely, as they act to limit polypharmacy and reduce prescription costs.