Diagnostic value of different adherence measures using electronic monitoring and virologic failure as reference standards

Increased adherence eight months after switch from twice daily calcineurin inhibitor based treatment to once daily modified released tacrolimus in heart transplantation

Background

Modified-release tacrolimus (TAC) is a new, once-daily oral formulation of the established immunosuppressive agent TAC. This study evaluated long-term patient adherence, as well as safety and efficacy, in stable patients after heart transplantation (HTx) who switched from a conventional twice daily calcineurin inhibitor-based regimen (TAC or cyclosporine A [CsA]) to a once-daily modified-release TAC regimen.

Methods

Stable patients were switched from conventional TAC or CsA (twice-daily dosing) to modified-release TAC (once-daily dosing) according to manufacturer’s recommendations using a pre-experimental design. Self-reported adherence was assessed at baseline and 8 months after the switch with the Basel Assessment of Adherence with Immunosuppressive Medication Scale (BAASIS). Additionally, routine laboratory values were analyzed 8 months after switch.

Results

Of 76 patients (58 male, 18 female) initially included, 72 were available for statistical analysis, as modified-release TAC was discontinued due to diarrhea in one patient and gastrointestinal discomfort in three patients. Overall nonadherence at baseline for any of the four BAASIS items was 75.0% versus 40.3% after 8 months (P<0.0001). After 8 months, adherence was improved in 41 patients (56.9%), unchanged in 27 (37.5%), and reduced in four patients (5.6%). The BAASIS visual analog scale score improved significantly from 87.0% ± 13.5% to 97.5% ± 5.7% (P<0.0001). No significant changes were observed for hematological, renal, or liver function parameters after 8 months (all P=not significant).

Conclusion

To our knowledge, this is the first study in stable patients after HTx to demonstrate a significant improvement in long-term (ie, 8-month) patient adherence after the switch to modified-release TAC. Modified-release TAC was generally well tolerated. Further studies are currently underway to investigate long-term safety after HTx of various calcineurin inhibitors for prevention of rejection and occurrence of side effects.

Provider guidance for linking patients to antiretroviral therapy adherence interventions: recommendations from an IAPAC advisory committee on adherence monitoring and support

High, persistent levels of antiretroviral therapy (ART) adherence are generally required to achieve sustained virologic suppression. Recently published global guidelines on entry into and retention in care and ART adherence include recommendations for monitoring and supporting ART adherence as a standard part of HIV clinical management. Several tools to facilitate the dissemination and implementation of these evidence-based guidelines are under development. A pocket-size Guidelines Regimen Information Program (GRIP) guide was recently developed as a quick reference tool to summarize high impact, strong evidence-based recommendations and to provide a validated single assessment item for use in collecting self-reported adherence estimations from patients as part of standard clinical care. The tool's development and intended use are reviewed and additional recommendations provided to facilitate a brief clinician-patient discussion to link patients to appropriate resources, strategies, or programs. Limitations of the tool and scenarios to avoid are also discussed. With a sizable proportion of individuals on ART trying to achieve or sustain sufficiently high rates of adherence, proactive monitoring of ART adherence and linkage of patients to needed resources is a critical component of high-quality HIV care. The quick reference GRIP guide is intended to be a part of a larger package of approaches to identify patients in need of adherence support regardless of current viral load and to help providers link patients with the available resources.

Relationship between viral load and self-report measures of medication adherence among youth with perinatal HIV infection

Poor adherence to antiretroviral therapy (ART) contributes to disease progression and emergence of drug-resistant HIV in youth with perinatally acquired HIV infection (PHIV +), necessitating reliable measures of adherence. Although electronic monitoring devices have often been considered the gold-standard assessment in HIV research, they are costly, can overestimate nonadherence and are not practical for routine care. Thus, the development of valid, easily administered self-report adherence measures is crucial for adherence monitoring. PHIV+youth aged 7-16 (n = 289) and their caregivers, enrolled in a multisite cohort study, were interviewed to assess several reported indicators of adherence. HIV-1 RNA viral load (VL) was dichotomized into >/≤ 400 copies/mL. Lower adherence was significantly associated with VL >400 copies/mL across most indicators, including ≥ 1 missed dose in past seven days [youth report: OR = 2.78 (95% CI, 1.46-5.27)]. Caregiver and combined youth/caregiver reports yielded similar results. Within-rater agreement between various adherence indicators was high for both youth and caregivers. Inter-rater agreement on adherence was moderate across most indicators. Age ≥ 13 years and living with biological mother or relative were associated with VL >400 copies/mL. Findings support the validity of caregiver and youth adherence reports and identify youth at risk of poor adherence.

The role of depression in medication adherence among heart failure patients

The purpose of the study was to explore the association between depression and medication adherence in heart failure (HF) patients. Studies have shown that people with depression are likely to be nonadherent to their prescribed medication treatment. But other studies suggest that nonadherence may be overestimated by people with depression. A total of 244 adults with Stage C HF completed the study. Self-reported medication adherence was obtained using the Basel Assessment of Adherence Scale (BAAS); objective data on medication adherence were collected using the electronic Medication Event Monitoring System (MEMS). Depression was measured via self-report with the Patient Health Questionnaire (PHQ-9). There was a significant difference between depressed and nondepressed participants in self-reported medication nonadherence (p = .008), but not in objectively measured medication nonadherence (p = .72). The depressed sample was 2.3 times more likely to self-report poor medication adherence than those who were nondepressed (p = .006).

A proposal for quality standards for measuring medication adherence in research

A decade after widespread recognition that adherence to medication regimens is key to antiretroviral effectiveness, considerable controversy remains regarding a "gold standard" for adherence measurement. Each adherence measurement approach has strengths and weaknesses and each rests on specific assumptions. The range of assumptions regarding adherence measurement and the diversity with which each approach is implemented strongly suggest that the evaluation of a particular measure outside of the context in which it was used (e.g. the study's operational protocol) may result in undeserved confidence or lack of confidence in study results. The purpose of this paper is to propose a set of best practices across commonly used measurement methods. Recommendations regarding what information should be included in published reports regarding how adherence was measured are provided to promote improvement in the quality of measurement of medication adherence in research.

Approaches to identifying appropriate medication adherence assessments for HIV infected individuals with comorbid bipolar disorder

Assessing medication adherence in already difficult-to-treat HIV-infected subpopulations presents a unique challenge. The objective of this study was to compare different approaches to assessing medication adherence: (1) electronic medication monitoring, (2) standardized self-report questionnaire, and (3) self-report visual analogue scale, and to determine whether antiretroviral therapy (ART) adherence measures differed for HIV-infected persons with bipolar disorder (HIV+ /BD+) as compared to HIV-infected persons without bipolar disorder (HIV+ /BD-). ART adherence was assessed for 74 HIV-positive participants using the Medication Event Monitoring System (MEMS), AIDS Clinical Trials Group (ACTG) adherence questionnaire, and visual analogue scale (VAS). Participants were classified as adherent or nonadherent on each measure by previously validated cutscores. Correlations and logistic regressions were used to examine associations between adherence measures and demographic and clinical variables. In the HIV+ /BD- group, significant correlations existed between each self-report measure and the MEMS. Males comprised 81% of the study population. Participants averaged 44 years of age and 13 years of education. No significant correlations were found among adherence measures in the HIV+ /BD+ group. Among participants reporting adherence on either self-report measure but classified as nonadherent based on MEMS, 94% had a diagnosis of bipolar disorder. Bipolar disorder was a significant predictor of adherence classification discordance among self-report measures. Our findings suggest that it remains difficult to assess ART adherence among HIV-positive individuals with bipolar disorder. Combined approaches of self-report and objective measures may be the best way to estimate adherence, and may provide the best basis for interventions designed to improve adherence in difficult-to-treat populations.

Active cocaine use is associated with lack of HIV-1 virologic suppression independent of nonadherence to antiretroviral therapy: use of a rapid screening tool during routine clinic visits

Clarifying the relationship between illicit drug use and HIV-1 virologic suppression requires characterization of both illicit drug use activity and adherence to antiretroviral therapy (ART). We developed a rapid clinical questionnaire to assess prior 7-day illicit drug use and ART adherence in a cross-sectional study among 1777 HIV-infected persons in care. Of these, 76% were male, 35% were African-American, and 8% reported injection drug use as their probable route of HIV-1 infection. Questionnaire-reported frequencies of cocaine and marijuana use within the previous 7 days were 3.3% and 12.1%, respectively. Over three quarters (77.8%) of participants were on ART, of whom 69.7% had HIV-1 virologic suppression (HIV-1 RNA<48 copies/mL). Univariate analyses revealed that compared to no use, cocaine and marijuana use were both associated with missed ART doses (P<0.01). Multivariable logistic regression analysis adjusting for nonadherence demonstrated that cocaine use was independently associated with failing to achieve virologic suppression (adjusted odds ratio (aOR): 0.46; 95% confidence interval (95% CI): 0.22-0.98) but marijuana use was not (aOR: 1.08; 95% CI: 0.72-1.62). This result strengthens the evidence of a direct effect of cocaine on virologic control, independent of nonadherence to ART.

Guidelines for improving entry into and retention in care and antiretroviral adherence for persons with HIV: evidence-based recommendations from an International Association of Physicians in AIDS Care panel

DESCRIPTION

After HIV diagnosis, timely entry into HIV medical care and retention in that care are essential to the provision of effective antiretroviral therapy (ART). Adherence to ART is among the key determinants of successful HIV treatment outcome and is essential to minimize the emergence of drug resistance. The International Association of Physicians in AIDS Care convened a panel to develop evidence-based recommendations to optimize entry into and retention in care and ART adherence for people with HIV.

METHODS

A systematic literature search was conducted to produce an evidence base restricted to randomized, controlled trials and observational studies with comparators that had at least 1 measured biological or behavioral end point. A total of 325 studies met the criteria. Two reviewers independently extracted and coded data from each study using a standardized data extraction form. Panel members drafted recommendations based on the body of evidence for each method or intervention and then graded the overall quality of the body of evidence and the strength for each recommendation.

RECOMMENDATIONS

Recommendations are provided for monitoring entry into and retention in care, interventions to improve entry and retention, and monitoring of and interventions to improve ART adherence. Recommendations cover ART strategies, adherence tools, education and counseling, and health system and service delivery interventions. In addition, they cover specific issues pertaining to pregnant women, incarcerated individuals, homeless and marginally housed individuals, and children and adolescents, as well as substance use and mental health disorders. Recommendations for future research in all areas are also provided.

Self-reported non-adherence and beliefs about medication in a Swedish kidney transplant population

Background:

Patients’ non-adherence to immunosuppressant treatment after organ transplantation may lead to organ failure, graft loss and death. Non-adherence among Swedish kidney transplant recipients has not previously been studied. Hence the aim of this study was to explore non-adherence among Swedish kidney transplant recipients by using self-report instruments as well as testing the hypothesis that there is a difference in self-reported symptoms, beliefs about medicine and social support between respondents with or without self reported non-adherence.

Materials and Methodology:

In the present cross sectional study 250 renal transplant recipients participated by replying to a questionnaire. Two validated instruments were included, one on beliefs about medicine (the BMQ©), the other on nonadherence (the BAASIS©).

Results:

Only 46 % never failed to follow the medical treatment with respect to taking the drugs, dosage or timing (>2 hrs from prescribed time). Timing was the most frequently reported deviation (48 %). Forty-seven patients (16 %) had failed taking at least one dose of the prescribed immunosuppressants during the past four weeks. Four individuals had reduced the prescribed doses. Only one reported taking a ‘drug holiday’. Nine participants reported stronger concerns than necessities for immunosuppressive medication. For the BMQ the necessity scores were extremely high while the scores for concern were low. Risk behaviour identified by the BAASIS had no association in risk attitudes as identified in the BMQ. The only factor relating to non-adherence was lack of social support (p=0.022).

Conclusion:

In general adherence was high. Identification of the exceptions remains a challenge.

Comparison of antiretroviral adherence questions

Our objective was to compare antiretroviral adherence questions to better understand concordance between measures. Among 53 methadone maintained HIV-infected drug users, we compared five measures, including two single item measures using qualitative Likert-type responses, one measure of percent adherence, one visual analog scale, and one multi-item measure that averaged responses across antiretrovirals. Responses were termed inconsistent if respondents endorsed the highest adherence level on at least one measure but middle levels on others. We examined ceiling effects, concordance, and correlations with VL. Response distributions differed markedly between measures. A ceiling effect was less pronounced for the single-item measures than for the measure that averaged responses for each antiretroviral: the proportion with 100% adherence varied from 22% (single item measure) to 58% (multi-item measure). Overall agreement between measures ranged from fair to good; 49% of participants had inconsistent responses. Though responses correlated with VL, single-item measures had higher correlations. Future studies should compare single-item questions to objective measures.

Practical and analytic issues in the electronic assessment of adherence

Although medication adherence can be measured many ways, researchers often view electronic dose monitoring devices like the Medication Event Monitoring Systems (MEMS) as more valid than patient self-reports. MEMS are popular but have potential problems. Based on the literature and MEMS data analyses, the authors suggest the following approaches: (a) a 1- to 2-month run-in should be used to reduce MEMS reactivity, (b) MEMS should be used with other measures of adherence, (c) adherence should be measured continuously, or a cutoff should be defined based on pharmacological properties of the medication and the consequences of nonadherence, (d) MEMS data usually should be aggregated weekly or monthly and evaluated using multilevel modeling, (e) MEMS-based screening for nonadherence may miss some patients in need of intervention, and (f) researchers should use strategies like training patients to use MEMS and purchasing extra MEMS caps to improve the completeness and accuracy of MEMS data.

Increased adherence after switch from twice daily calcineurin inhibitor based treatment to once daily modified released tacrolimus in heart transplantation: a pre-experimental study

BACKGROUND

Modified release tacrolimus (TAC) is a new, once-daily oral formulation of the established immunosuppressive agent TAC. Simplification of regimen has been associated with better adherence. This study evaluated patient adherence, as well as safety and efficacy among chronic stable heart transplantation (HT) patients switched from a conventional twice daily calcineurin inhibitor-based regimen (TAC or cyclosporine A [CsA]) to (once daily) modified release TAC.

METHODS

We switched 54 chronic stable patients (41 males and 13 females) from twice daily dosing with conventional TAC or CsA to once daily dosing with modified release TAC. Self-reported adherence was assessed at baseline and at 4 months after the switch using the Basel Assessment of Adherence with Immunosuppressive Medication Scale [BAASIS]), a 4-item validated questionnaire including also a Visual Analogue Scale (VAS). Nonadherence was defined as any self-reported nonadherence on any item.

RESULTS

Modified release TAC was discontinued in 4 patients because of diarrhea (n = 1) or gastrointestinal discomfort (n = 3) leaving 50 evaluable patients. Overall nonadherence at baseline for any of the 4 items was 74% versus 38% after 4 months (P = .0001). Thereafter, adherence improved in 28 patients (56.0%), was unchanged in 18 (36.0%), and decreased in 4 subjects (8.0%). The VAS score improved from 82.3% ± 2.6% to 97.5% ± 4.8% (P < .0001). No significant changes were observed after 4 months regarding hematologic, renal, or liver function parameters (all P = NS).

CONCLUSIONS

Therapeutic regimens for transplant recipients are often complex, contributing to a high incidence of medication nonadherence. This study in chronic, stable, heart transplantation patients demonstrated a significant improvement in patient adherence after a switch to modified release TAC, which was generally well tolerated.

Evaluating counseling outcome on adherence to prophylaxis and follow-up after sexual HIV-risk exposure: a randomized controlled trial

OBJECTIVE

Post-exposure prophylaxis (PEP) is recommended for the management of sexual HIV-risk exposure. However, a high percentage of exposed patients discontinue both their 28-day prophylaxis course before 15 days and HIV testing follow-up before M3. The objective of this study is to assess the efficacy of a counseling intervention in enhancing both adherence to PEP and HIV testing follow-up.

METHODS

Between 1 June 2004 and 31 December 2005, 54 patients exposed to sexual HIV-risk exposure were included in a multicenter, prospective, controlled, randomized trial, comparing a group receiving a counseling intervention in addition to traditional medical management (intervention group (IG), n=28) vs. a control group (CG, n=26). Patients in the IG received interactive counseling interventions focused on adherence to PEP and to HIV testing follow-up, led by specially trained nurses. The main outcome measures were proportion of patients achieving 100% adherence to PEP as evaluated on D15 by a self-completed patient questionnaire and on HIV testing on D45 and M3.

RESULTS

Groups were well balanced at baseline for age, sex, and circumstances of exposure. The proportion of 100% adherent patients to PEP was significantly higher in the IG compared to the CG (54% vs. 23%, p=0.036). Patients in the IG were more likely to complete the HIV testing follow-up at D45 (86% vs. 54%, p=0.023) and M3 (68% vs. 38%, p=0.056).

CONCLUSIONS

This study suggests the effectiveness of a counseling program to enhance adherence to both PEP and HIV testing follow-up after sexual exposure.

Validating five questions of antiretroviral nonadherence in a public-sector treatment program in rural South Africa

Simple questions are the most commonly used measures of antiretroviral treatment (ART) adherence in sub-Saharan Africa (SSA), but rarely validated. We administered five adherence questions in a public-sector primary care clinic in rural South Africa: 7-day recall of missed doses, 7-day recall of late doses, a six-level Likert item, a 30-day visual analogue scale of the proportion of doses missed, and recall of the time when an ART dose was last missed. We estimated question sensitivity and specificity in detecting immunologic (or virologic) failure assessed within 45 days of the adherence question date. Of 165 individuals, 7% had immunologic failure; 137 individuals had viral loads with 9% failure detected. The Likert item performed best for immunologic failure with sensitivity/specificity of 100%/5% (when defining nonadherence as self-reported adherence less than "excellent"), 42%/55% (less than "very good"), and 25%/95% (less than "good"). The remaining questions had sensitivities ≤17%, even when the least strict cutoffs defined nonadherence. When we stratified the analysis by gender, age, or education, question performance was not substantially better in any of the subsamples in comparison to the total sample. Five commonly used adherence questions performed poorly in identifying patients with treatment failure in a public-sector ART program in SSA. Valid adherence measurement instruments are urgently required to identify patients needing treatment support and those most at risk of treatment failure. Available estimates of ART adherence in SSA are mostly based on studies using adherence questions. It is thus unlikely that our understanding of ART adherence in the region is correct.

Measuring adherence to antiretroviral therapy in northern Tanzania: feasibility and acceptability of the Medication Event Monitoring System

BACKGROUND

An often-used tool to measure adherence to antiretroviral therapy (ART) is the Medication Event Monitoring System (MEMS), an electronic pill-cap that registers date and time of pill-bottle openings. Despite its strengths, MEMS-data can be compromised by inaccurate use and acceptability problems due to its design. These barriers remain, however, to be investigated in resource-limited settings. We evaluated the feasibility and acceptability of using MEMS-caps to monitor adherence among HIV-infected patients attending a rural clinic in Tanzania's Kilimanjaro Region.

METHODS

Eligible patients were approached and asked to use the MEMS-caps for three consecutive months. Thereafter, qualitative, in-depth interviews about the use of MEMS were conducted with the patients. MEMS-data were used to corroborate the interview results.

RESULTS

Twenty-three of the 24 patients approached agreed to participate. Apart from MEMS-use on travel occasions, patients reported no barriers regarding MEMS-use. Unexpectedly, the MEMS-bottle design reduced the patients' fear for HIV-status disclosure. Patients indicated that having their behavior monitored motivated them to adhere better. MEMS-data showed that most patients had high levels of adherence and there were no bottle-openings that could not be accounted for by medication intake. Non-adherence in the days prior to clinic visits was common and due to the clinic dispensing too few pills.

CONCLUSION

MEMS-bottle use was readily accepted by patients. Although the MEMS-bottle was used accurately by most patients, patients need to be more explicitly instructed to continue MEMS-use when travelling. Even HIV-clinics with sufficient staff and free medication may impose structural adherence barriers by supplying an insufficient amount of pills.

Excessive daytime sleepiness is associated with poor medication adherence in adults with heart failure

BACKGROUND

A relationship between excessive daytime sleepiness (EDS) and poor treatment adherence has been suspected but not confirmed. We hypothesized that medication adherence would be poorer in adults with heart failure (HF) and EDS and that cognitive status would be the mechanism of effect.

METHODS AND RESULTS

A sample of 280 adults with chronic HF were enrolled into a prospective cohort comparison study. We identified a cohort with EDS and a control group without EDS and further divided both groups into those with and without mild cognitive decline. Data on medication adherence were obtained at baseline and 3 and 6 months by using the Basel Assessment of Adherence Scale. Regression analysis was used to clarify the contribution of EDS and cognition to medication adherence and to assess relationships over 6 months after adjusting for age, enrollment site, gender, race, functional class, depression, and premorbid intellect. At baseline, 62% of subjects were nonadherent to their medication regime. Nonadherence was significantly more common in those with EDS, regardless of cognitive status (P = .035). The odds of nonadherence increased by 11% for each unit increase in EDS (adjusted odds ratio 1.11; 95% confidence interval 1.05-1.19; P = .001). In longitudinal models, there was a 10% increase in the odds of nonadherence for each unit increase in EDS (P = .008). The only cognition measure significantly associated with medication adherence was attention (P = .047).

CONCLUSIONS

Adults with HF and EDS are more likely to have problems adhering to their medication regimen than those without EDS, regardless of their cognitive status. Identifying and correcting factors that interfere with sleep may improve medication adherence.

The psychometric properties and practicability of self-report instruments to identify medication nonadherence in adult transplant patients: a systematic review

INTRODUCTION

Nonadherence to immunosuppressive therapy is recognized as a key prognostic indicator for poor posttransplantation long-term outcomes. Several methods aiming to measure medication nonadherence have been suggested in the literature. Although combining measurement methods is regarded as the gold standard for measuring nonadherence, self-report is generally considered a central component of adherence assessment. However, no systematic review currently exists to determine which instrument(s) are most appropriate for use in transplant populations.

METHODOLOGY

The transplant360 Task Force first performed a survey of the self-report adherence instruments currently used in European centers. Next, a systematic literature review of self-report instruments assessing medication adherence in chronically ill patients was conducted. Self-report instruments were evaluated to assess those which were: (a) short and easy to score; (b) assessed both the taking and timing of medication intake; and (c) had established reliability and validity.

RESULTS

Fourteen instruments were identified from our survey of European centers, of which the Basel Assessment of Adherence Scale for Immunosuppressives met the aforementioned criteria. The systematic review found 20 self-report instruments, of which only two qualified for use in transplantation, that is, the Brief Antiretroviral Adherence Index and the Medication Adherence Self-Report Inventory.

DISCUSSION

The three selected self-report scales may assist transplant professionals in detecting nonadherence. However, these scales were only validated in patients with HIV. Although HIV shares similar characteristics with transplantation, including the importance of taking and timing of medication, further validation in transplant populations is required.

[Evolution of antiretroviral treatment adherence from 2000 to 2008]

OBJECTIVES

To evaluate antiretroviral treatment adherence in the HIV patient cohort of our hospital and observe their evolution over a 9-year period; also to determine the individual pattern of adherence over time.

METHODS

Descriptive study of the evolution of average annual adherence and the annual percentage of adherent patients greater than 95% from 2000 to 2008. We analysed the individual pattern of adherence over time and patients were classified into consistently adherent, consistently non-adherent, and fluctuating.

RESULTS

In the analysis of 577 patients, baseline adherence was significantly greater in naïve patients with respect to those who were pre-treated. Average annual adherence increased slightly and stayed at values around 95%. As with the percentage of patients with adherence greater than 95%, which increased from 64% in 2000 to 79% in 2008. In terms of the individual pattern of adherence over time, of the 468 patients analysed, the majority (59%) were consistently adherent, 4% non-adherent, and the rest (37%) fluctuated in their adherence.

CONCLUSIONS

In our cohort the overall adherence values maintained themselves over time and even show a positive trend, likely the result of systematic monitoring of adherence and implementation strategies to maintain adherence.

A simple single-item rating scale to measure medication adherence: further evidence for convergent validity

BACKGROUND

Self-report measures of medication adherence are inexpensive and minimally intrusive. However, the validity of self-reported adherence is compromised by recall errors for missed doses and socially desirable responding.

METHOD

Examined the convergent validity of 2 self-report adherence measures administered by computerized interview: (a) recall of missed doses and (b) a single-item visual analogue rating scale (VAS). Adherence was also monitored using unannounced phone-based pill counts that served as an objective benchmark.

RESULTS

The VAS obtained adherence estimates that paralleled unannounced pill counts (UPCs). In contrast, self-reported recall (SR-recall) of missed medications consistently overestimated adherence. Correlations with participant characteristics also suggested that the computer-administered VAS was less influenced by response biases than SR-recall of missed medication doses.

CONCLUSIONS

A single-item VAS offers an inexpensive and valid method of assessing medication adherence that may be useful in clinical as well as research settings.

Validity of the adherence estimator in the prediction of 9-month persistence with medications prescribed for chronic diseases: a prospective analysis of data from pharmacy claims

OBJECTIVE

The aim of this article was to assess the predictive validity of the Adherence Estimator--a 3-item instrument designed to estimate a patient's propensity to adhere to medications prescribed for chronic disease.

METHODS

The Adherence Estimator was a 3-item part of a larger survey mailed to adults aged >or=40 years who had a qualifying index prescription filled in June 2008. A qualifying prescription was defined as one for a medication indicated for the treatment of 1 of 5 chronic diseases (cardiovascular disease, dyslipidemia [lipid-lowering drugs], diabetes [oral antihyperglycemics], osteoporosis [oral bisphosphonates], or asthma). Outcomes were compared between the adherence risk groups derived from the Adherence Estimator (low risk = score of 0, medium risk = score of 2-7, and high risk = score of 8-36). Treatment persistence over a period of 9 months was measured using pharmacy claims data. The primary outcome was the median proportion of days covered (PDC) by >or=1 medication during the first 9 months after the index fill. Secondary outcomes included adherence to the index medication, defined as PDC dichotomized to >or=0.80 or <0.80; rate of obtaining a second fill within 30 days of the index fill; and medication possession ratio (MPR) for refill adherence.

RESULTS

There were 1676 usable responses. Ages ranged from 40 to 88 years, with a mean of 64.6 years. Almost two thirds (1076/1676 [64.2%]) of the sample were female, and 1483/1676 (88.5%) were white. Statistically significant associations for all 3 pairwise comparisons (low vs medium risk, low vs high risk, and medium vs high risk) were observed between the Adherence Estimator risk groups for: (1) median PDC (0.655, 0.598, and 0.484 in the low-, medium-, and high-risk groups, respectively [all, false discovery rate [FDR] <0.05]); (2) PDC categorized (293/711 [41.21%], 200/588 [34.01%], and 105/377 [27.85%] [all, FDR <0.05]); and (3) rate of obtaining a second fill for the index medication within 30 days (489/711 [68.78%], 374/588 [63.61%], and 207/377 [54.91%] [all, FDR <0.05]). The low- and high-risk groups differed from one another on: (1) persistence with the index medication at 9 months (265/711 [37.27%] and 95/377 [25.20%]); (2) persistence with >1 medication at 9 months (291/711 [40.93%] and 108/377 [28.65%]); and (3) obtaining a second fill for any medication within 30 days (501/711 [70.46%] and 219/377 [59.09%]) (all, P < 0.05). The low- and high-risk groups differed significantly from one another in MPR for refill adherence (0.912 vs 0.866). Results observed within diseases mirrored those for the total sample, but with less precision.

CONCLUSION

In the present analysis of the validity of the Adherence Estimator in predicting adherence, baseline propensity to adhere to medications prescribed for chronic diseases was statistically associated with several measures of adherence and persistence, as derived from pharmacy claims data, over a 9-month period.

Improving the self-report of HIV antiretroviral medication adherence: is the glass half full or half empty?

Self-reports are the most widely used method for measuring antiretroviral adherence. The association between self-reports and viral loads has been repeatedly demonstrated, but this association does not address how well self-reports measure actual medication-taking behaviors. Understanding adherence self-reports requires studying the science of memory and the reporting of behaviors. In the first section of this review, we discuss research in cognitive psychology that pertains to adherence self-reports, focusing primarily on studies that examine cognitive processes respondents use to answer survey questions. In the second section, we review recent articles examining the relationship between self-reports and objective measures of adherence, highlighting the strength of associations and key methodologic issues. We conclude with key questions for future research and methodologic recommendations.

An evidence-based review of treatment-related determinants of patients' nonadherence to HIV medications

Patients' adherence to antiretroviral medications is a primary determinant of both the effectiveness of treatment and the clinical course of HIV/AIDS. This empirical review is intended to compare the relative importance of patient and treatment characteristics on nonadherence behavior and the impact of nonadherence on treatment failure. Articles cited in PubMed and published between 2006 and June 2008 (n = 200) were reviewed to select those that address patient or treatment characteristics associated with nonadherence. Twenty-two articles were selected that provided odds ratio or hazard ratio statistics that quantified predictors of patients' level of nonadherence (e.g., <80%, 80%-95% and >95%). Results were summarized using random effects meta-analytic models. Predictors of nonadherence were divided into four predictive clusters (clinical predictors, comorbid predictors, treatment competence predictors, and dosing predictors). The summary odds ratios (ORs) of nonadherence for each cluster (in order of strength) were treatment competence 2.0 (95% confidence interval [CI]: 1.6-2.6), clinical predictors 1.6 (95% CI: 1.4-1.8), comorbid predictors 1.6 (95% CI: 1.4-1.8), and dosing predictors 1.5 (95% CI: 1.3-1.7). The effect of nonadherence on treatment failure supported the findings of two prior empirical reviews (OR 2.0, 95% CI: 1.6-2.5). Within dosing predictors, a pill burden of more versus less than 10 pills per day was associated with a much higher odds of nonadherence than twice versus once daily dosing or small differences in the number of types of antiretroviral treatments in a regimen. These results provide insight into the relative importance of various determinants of patient nonadherence that may inform the design of patient educational initiatives and initiatives to simplify treatment regimens.

Piloting a peer-driven intervention model to increase access and adherence to antiretroviral therapy and HIV care among street-entrenched HIV-positive women in Vancouver

A peer-driven intervention (PDI) was developed to support uptake and adherence to highly active antiretroviral therapy (HAART) among women sex workers who use illicit substances in Vancouver, because uptake and adherence continues to be suboptimal. Trends of adherence were examined among women in this program by (1) exposure to the intervention and (2) risk behaviors including drug use and unstable housing. Between January 2007 and January 2008, 20 HIV-positive women were enrolled into the PDI on a rolling basis. PDI participation included weekly peer support meetings, a health advocate (buddy) system, peer outreach service, and onsite nursing care. Adherence was measured directly with pharmacy records (PR) and indirectly with self-report and viral load (VL) outcomes. Participants attended an average of 50 (21-70) PDI meetings. Overall self-reported adherence was high (92%) and most women (11) reported increased adherence from the first to the last 13 PDI meetings attended (average increase = 18%). The number of viral load tests <or=50 copies/mL increased by 40% from the pre-PDI period (1 year before enrollment), to the PDI period (duration enrolled). PR adherence and improvements in VL outcomes were higher among participants with greater housing instability and frequency of injecting/smoking drugs. Despite a very difficult environment to provide HIV care, there is evidence to suggest that the PDI may have had a positive impact on adherence outcomes. Although this would not predict long-term treatment success, the PDI approach to HIV treatment support is a promising program for women who might otherwise be excluded from treatment altogether.

A comparison of adherence assessment methods utilized in the United States: perspectives of researchers, HIV-infected children, and their caregivers

This study sought to elucidate methodological issues in adherence research by comparing multiple methods of assessing adherence to antiretroviral medication. From 2003 to 2004, 24 youths with vertically infected HIV disease (mean age = 14.0 years; range, 8-18) and their caregivers participated in a 6-month study. These children were all on highly active antiretroviral therapy (HAART) and were relatively healthy (mean CD4 absolute count = 711.8 +/- 604.5). Adherence was assessed with the Medication Event Monitoring System (MEMS), pill counts, and interviews. Patients and caregivers completed the Perceptions of Adherence Study Participation (PASP) questionnaire. MEMS provided the most detailed adherence information, and good reliability was indicated by significant correlations with medical markers. Pill counts provided similar adherence rates, while patients and caregivers reported nearly perfect adherence in interviews. Problems were experienced with each method: MEMS were expensive, had cap malfunctions, and lack a consistent guiding principle for data interpretation. With pill counts, families forgot to bring all medication bottles to clinic, and interviews were compromised by social desirability and difficulty reaching families by telephone. Most patients and caregivers believed study participation improved the child's adherence, although PASP ratings were unrelated to adherence at the study endpoint. While MEMS may be most reliable, pill counts offer comparable data and are less costly, while interviews seemed least accurate in this study. Most participants reported positive perceptions of their research experience. A consensus among researchers is needed for defining and measuring adherence, and specific recommendations are offered for achieving this goal.

The impact of neuropsychological functioning on adherence to HAART in HIV-infected substance abuse patients

This study assessed the frequency of neuropsychological impairment and its relationship to adherence in a sample of HIV-infected injection drug users (IDUs) in treatment. One hundred eight participants recruited between September 2006 and October 2008 completed psychodiagnostic and neuropsychological assessments and monitored HAART adherence over a 2-week period via the use of Medication Event Monitoring System (MEMS) electronic pill caps and self-report. Assessment of concurrent functioning included clinician-rated scales of depression and substance use severity, and a battery of neuropsychological tests. Findings from individual neuropsychological tests were converted to Z scores relative to standard norms and averaged to form a composite score (NPZ). NPZ was generally poor (mean = -1.505, standard deviation = 1.120), with 76.9% of the sample being classified as highly impaired. Self-reported adherence was significantly higher than MEMS cap adherence. In contrast with previous studies, overall neuropsychological functioning was not a significant predictor of electronically monitored or self-reported adherence. However, examiner-rated current global severity of substance use and delayed word list recall emerged as significant predictors of self-reported adherence. Additionally, estimated premorbid verbal intelligence emerged as a significant predictor of the discrepancy between electronically monitored and self-reported adherence. Given the extent of neuropsychological impairment in this sample, future studies should examine the degree to which the impact of neuropsychological impairment may moderate interventions for this population, and the extent to which skills to cope with neuropsychological problems may boost the potential efficacy of such interventions.