Dynamics of drug regimen compliance--its assessment by microprocessor-based monitoring

Deception in clinical trials and its impact on recruitment and adherence of study participants

Deceptive practices by participants in clinical research are prevalent. It has been shown that as high as 75% of participants withheld information to avoid exclusion from studies. Self-reported adherence has been found to be largely inaccurate. Overcoming deception is a critical issue, since the safety of study participants, the integrity of research data and research resources are at risk. In this review article, we examine deception from the perspective of investigators conducting clinical trials; we describe the types (concealment, fabrication, drug holidays and collusion), prevalence, risks, and predictors of deception, and propose an approach to reduce the impact of deception, especially on adherence, in clinical trials.

Multiple Criteria Decision Analysis (MCDA) for evaluating new medicines in Health Technology Assessment and beyond: The Advance Value Framework

Escalating drug prices have catalysed the generation of numerous "value frameworks" with the aim of informing payers, clinicians and patients on the assessment and appraisal process of new medicines for the purpose of coverage and treatment selection decisions. Although this is an important step towards a more inclusive Value Based Assessment (VBA) approach, aspects of these frameworks are based on weak methodologies and could potentially result in misleading recommendations or decisions. In this paper, a Multiple Criteria Decision Analysis (MCDA) methodological process, based on Multi Attribute Value Theory (MAVT), is adopted for building a multi-criteria evaluation model. A five-stage model-building process is followed, using a top-down "value-focused thinking" approach, involving literature reviews and expert consultations. A generic value tree is structured capturing decision-makers' concerns for assessing the value of new medicines in the context of Health Technology Assessment (HTA) and in alignment with decision theory. The resulting value tree (Advance Value Tree) consists of three levels of criteria (top level criteria clusters, mid-level criteria, bottom level sub-criteria or attributes) relating to five key domains that can be explicitly measured and assessed: (a) burden of disease, (b) therapeutic impact, (c) safety profile (d) innovation level and (e) socioeconomic impact. A number of MAVT modelling techniques are introduced for operationalising (i.e. estimating) the model, for scoring the alternative treatment options, assigning relative weights of importance to the criteria, and combining scores and weights. Overall, the combination of these MCDA modelling techniques for the elicitation and construction of value preferences across the generic value tree provides a new value framework (Advance Value Framework) enabling the comprehensive measurement of value in a structured and transparent way. Given its flexibility to meet diverse requirements and become readily adaptable across different settings, the Advance Value Framework could be offered as a decision-support tool for evaluators and payers to aid coverage and reimbursement of new medicines.

Projected inhibition of platelet aggregation with ticagrelor twice daily vs. clopidogrel once daily based on patient adherence data (the TWICE project)

AIM

Twice daily dosing is often perceived as inferior to once daily dosing due to a higher likelihood of missing a dose. However, more important is the extent to which drug action is maintained when doses are delayed or missed. We compared the estimated inhibition of platelet aggregation (eIPA) for ticagrelor twice daily and clopidogrel once daily, based on their pharmacokinetic/ pharmacodynamic relationships and patient dosing history data.

METHODS

Drug dosing histories of 5014 patients prescribed cardiovascular medications (primarily antihypertensive medicines) were extracted from an electronically compiled dosing history database. eIPA levels were simulated for 677 twice daily and 677 once daily dosing histories over a 30 day period, based on published onset/offset models for ticagrelor and clopidogrel IPA characteristics.

RESULTS

While many patients treated twice daily missed at least one dose in 30 days, only 25.7% missed two consecutive doses. By comparison, 46.8% of patients treated once daily missed at least one dose. Simulations based on patient adherence over time showed that the average mean eIPA for ticagrelor twice daily remained significantly higher than for clopidogrel once daily (81.1% vs. 55.0%, P < 0.001). Ticagrelor twice daily patients had an eIPA below 10% for 0.20% of the 30 day period compared with 2.05% for clopidogrel once daily (P = 0.0001).

CONCLUSIONS

The projected level of platelet inhibition remained higher for ticagrelor twice daily than clopidogrel once daily, mainly due to the higher eIPA level achieved with ticagrelor and the relatively low likelihood of missing two consecutive twice daily doses. This modelling and simulation study suggests a therapeutic benefit of ticagrelor over clopidogrel when taking into account the most common dosing omissions.

Adherence to antidepressant combinations and monotherapy for major depressive disorder: a CO-MED report of measurement-based care

BACKGROUND

Non-adherence to antidepressant treatment is not routinely measured in practical clinical trials. It has not been related to outcomes in a large sample of adults with chronic and/or recurrent major depressive disorder (MDD) or any sample treated with antidepressant combinations.

METHODS

Adult outpatients with chronic and/or recurrent MDD were randomized to 12 weeks of treatment with bupropion-SR plus escitalopram, venlafaxine-XR plus mirtazapine, or escitalopram plus placebo. We compared non-adherence (the frequency with which daily medications were not taken) and specifically the frequency of temporarily stopping and/or skipping medication, or reducing or increasing the dose across treatments in 567 participants using a self-report questionnaire collected at each visit. We tested the association between non-adherence, and both treatment type and outcomes.

RESULTS

A non-adherence rate under 10% was reported by 77.9%, 70.9%, and 71.6% of participants during weeks 1-4, 5-12, and 1-12, respectively. Antidepressant combinations were associated with a higher non-adherence rate than monotherapy during weeks 1-4 and 1-12. During weeks 1-4, 24.1% stopped/skipped doses and 6.1% reduced the dose. During weeks 5-12, 34.7% stopped/skipped doses and 9.4% reduced the dose. Across 12 weeks, 43.2% stopped/skipped doses, and 12.9% reduced the dose. Stopping/skipping doses during all time frames and dose decreases during weeks 1-12 occurred most frequently with combination treatments. Non-adherence was unrelated to symptom remission, response, or symptom change.

CONCLUSIONS

With closely monitored treatment, non-adherence is low and unrelated to depressive symptom outcome. Nonadherence is highest with antidepressant combinations. Specific non-adherent events are most often sporadic.

Improving Maintenance Medication Adherence in Adult Inflammatory Bowel Disease Patients: A Pilot Study

Medication nonadherence in inflammatory bowel disease (IBD) may lead to suboptimal control of the disease, decreased quality of life, and poor outcomes. This pilot study evaluated the feasibility, intervention mechanism, and potential effectiveness of a three-month continuous self-improvement (CSI) intervention to enhance medication adherence (MA) in adult nonadherent IBD patients. Adult IBD patients taking a daily or twice-daily dosed maintenance medication were screened electronically for two months to determine baseline MA levels. Nonadherent IBD participants were randomized to the CSI or the attention control (AC) intervention and monitored for three months. The CSI intervention consisted of a data evaluation and system refinement process in which system changes were identified and implemented. The AC group was given educational information regarding IBD disease process, extra-intestinal manifestations of IBD, and medical therapy. Demographic statistics, change scores for within and between-group differences, and effect size estimates were calculated. Nine nonadherent participants (medication adherence score <0.85) were eligible for randomization. The intervention was found feasible and acceptable. Although no statistically significant improvement in MA was found (P=0.14), adherence improved in 3 of 4 of the CSI group and 1 of 2 in the attention control group. The effect size calculation of 1.9 will determine the sample size for future study. The results of this pilot study showed the intervention was feasible and had a positive effect on MA change score and adherence levels. A larger fully powered study is needed to test of the effectiveness of this innovative intervention.

Adherence to raloxifene therapy: assessment methods and relationship with efficacy

Response to therapy depends on patient compliance but accurate assessment is difficult and adequate levels of adherence are uncertain. Adherence to raloxifene treatment may be assessed more accurately by electronic monitoring than by counting returned tablets. The level of adherence is positively associated with the degree of bone response.

INTRODUCTION

Adherence to study medication is usually estimated by counting returned tablets. This method relies on subjects' honesty and may be inaccurate. We aimed to assess adherence more accurately, and examine its effect on measures of bone response, by using electronic monitoring.

METHODS

Osteopenic women, ages 50 to 80, were prescribed daily raloxifene for 2 years. Electronic bottle caps (Medication Event Monitoring System (MEMS), Aardex) recorded the date and time on opening. Returned tablets were also counted. We measured bone mineral density (BMD) in duplicate at the spine and hip at baseline and 2 years. We also measured urinary N-terminal cross-linked telopeptide of type I collagen (NTX) at baseline, 1 and 2 years. We calculated the percentage changes in BMD and NTX from mean baseline to mean follow up measurements. Percentage adherence was assessed by both methods for 71 subjects that completed the study.

RESULTS

The two methods correlated significantly (p <0.001, Spearman's rho = 0.73) but the tablet count showed a higher median adherence than the MEMS caps (95.7 vs. 85.0%, p <0.001), with greater divergence at lower adherence levels. MEMS adherence in 65 subjects with complete data correlated with NTX response (p <0.01, rho = -0.33) but with BMD response only at the femoral neck. However, adherence in the lowest quartile was associated with poorer BMD response at all sites (p <0.05).

CONCLUSION

Tablet counts may give similar results overall but conceal substantial individual non-adherence. Monitoring caps may assess adherence more accurately than tablet counts and would be the preferred method in clinical trials. The degree of adherence is associated with both bone turnover and BMD responses to anti-resorptive therapy.

Promoting knowledge of statins in patients with low health literacy using an audio booklet

BACKGROUND

Statins are generally well tolerated and effective at reducing a patient's risk of both primary and secondary cardiovascular events. Many patients who would benefit from statin therapy either do not adhere to or stop taking their statin medication within the first year. We developed an audio booklet targeted to low health literacy patients to teach them about the benefits and risks of statins to help the patients adhere to their statin therapy.

METHODS

Through focus groups and an iterative design, an audio booklet was developed for both English-speaking and Spanish-speaking patients. We then compared the booklet with standard of care in 132 patients from our target patient population to measure its impact on knowledge and understanding of statins.

RESULTS

The patients enjoyed the audio booklet and showed significant increases in knowledge after listening to it when compared with those who received the standard of care materials.

CONCLUSION

The audio booklet shows promise as a tool that can be used effectively in clinical practice to teach patients about statin therapy.

Performance of Cpred/Cobs concentration ratios as a metric reflecting adherence to antidepressant drug therapy

BACKGROUND

Nonadherence is very common among subjects undergoing pharmacotherapy for schizophrenia and depression. This study aimed to evaluate the performance of the ratio of the nonlinear mixed effects pharmacokinetic model predicted concentration to observed drug concentration (ratio of population predicted to observed concentration (Cpred/Cobs) and ratio of individual predicted to observed concentration (Cipred/Cobs) as a measure of erratic drug exposure, driven primarily by variable execution of the dosage regimen and unknown true dosage history.

METHODS

Modeling and simulation approaches in conjunction with dosage history information from the Medication Event Monitoring System (MEMS, provided by the "Depression: The search for treatment relevant phenotypes" study), was applied to evaluate the consistency of exposure via simulation studies with scenarios representing a long half-life drug (escitalopram). Adherence rates were calculated based on the percentage of the prescribed doses actually taken correctly during the treatment window of interest. The association between Cpred/Cobs, Cipred/Cobs ratio, and adherence rate was evaluated under various assumptions of known dosing history.

RESULTS

Simulations for those scenarios representing a known dosing history were generated from historical MEMS data. Simulations of a long half-life drug exhibited a trend for overprediction of concentrations in patients with a low percentage of doses taken and underprediction of concentrations in patients taking more than their prescribed number of doses. Overall, the ratios did not predict adherence well, except when the true adherence rates were extremely high (greater than 100% of prescribed doses) or extremely low (complete nonadherence). In general, the Cipred/Cobs ratio was a better predictor of adherence rate than the Cpred/Cobs ratio. Correct predictions of extreme (high, low) 7-day adherence rates using Cipred/Cobs were 73.8% and 64.0%.

CONCLUSION

This simulation study demonstrated the limitations of the Cpred/obs and Cipred/obs ratios as metrics for actual dosage intake history, and identified that use of MEMS dosing history monitoring combined with sparse pharmacokinetic sampling is a more reliable approach.

Compliance with inhalatory therapy: an increasingly recognized clinical outcome

Compliance with medications is one of the major issues encountered in medical practice in the treatment of many chronic diseases, as it represents the interface between the effectiveness of the drug regimen and management of the disease. Noncompliance with inhalatory therapy could be the leading cause of poor disease control and increased morbidity in conditions, such as asthma or chronic obstructive pulmonary disease. The strongest predictors of compliance are represented by the marital status, age and education of the patient, however, more research is needed in this field. Psychological factors are also known to play a role, as does the medication regimen. Assessment methods most commonly used for inhalatory therapy are self-reporting and canister weight but electronic diaries and electronic monitoring devices are more promising and reliable. Educational interventions and disease self-management plans are known to be effective in improving compliance but more specific strategies must be established. Special attention is required in children and the elderly since the compliance-related issues in these populations are more complex.

Concordance of adherence measurement using self-reported adherence questionnaires and medication monitoring devices

The primary objective of this review was to identify and examine the literature on the association between medication adherence self-reported questionnaires (SRQs) and medication monitoring devices. The primary literature search was performed for 1980-2009 using PubMed, PubMed In Process and Non-Indexed, Ovid MEDLINE, Ovid MEDLINE In-Process, PsycINFO (EBSCO), CINAHL (EBSCO), Ovid HealthStar, EMBASE (Elsevier) and Cochrane Databases and using the following search terms: 'patient compliance', 'medication adherence', 'treatment compliance', 'drug monitoring', 'drug therapy', 'electronic', 'digital', 'computer', 'monitor', 'monitoring', 'drug', 'drugs', 'pharmaceutical preparations', 'compliance' and 'medications'. We identified studies that included SRQs and electronic monitoring devices to measure adherence and focused on the SRQs that were found to be moderately to highly correlated with the monitoring devices. Of the 1679 citations found via the primary search, 41 full-text articles were reviewed for correlation between monitoring devices and SRQs. A majority (68%) of articles reported high (27%), moderate (29%) or significant (12%) correlation between monitoring devices (37 using Medication Event Monitoring System [MEMS®] and four using other devices) and SRQs (11 identified and numerous other unnamed SRQs). The most commonly used SRQs were the Adult/Pediatric AIDS Clinical Trial Group (AACTG/PACTG; 24.4%, 10/41) followed by the 4-item Morisky (9.8%, 4/41), Brief Medication Questionnaire (9.8%, 4/41) and visual analogue scale (VAS; 7.3%, 3/41). Although study designs differed across the articles, SRQs appeared to report a higher rate of medication adherence (+14.9%) than monitoring devices. In conclusion, several medication adherence SRQs were validated using electronic monitoring devices. A majority of them showed high or moderate correlation with medication adherence measured using monitoring devices, and could be considered for measuring patient-reported adherence prospectively.

Patient adherence and the choice of antihypertensive drugs: focus on lercanidipine

Despite the development of many effective antihypertensive drugs, target blood pressures are reached in only a minority of patients in clinical practice. Poor adherence to drug therapy and the occurrence of side effects are among the main reasons commonly reported by patients and physicians to explain the poor results of actual antihypertensive therapies. The development of new effective antihypertensive agents with an improved tolerability profile might help to partly overcome these problems. Lercanidipine is an effective dihydropyridine calcium channel blocker of the third generation characterized by a long half-life and its lipophylicity. In contrast to first-generation dihydropyridines, lercanidipine does not induce reflex tachycardia and induces peripheral edema with a lower incidence. Recent data suggest that in addition to lowering blood pressure, lercanidipine might have some renal protective properties. In this review we shall discuss the problems of drug adherence in the management of hypertension with a special emphasis on lercanidipine.

Dose timing and patient compliance with two antibiotic treatment regimens for lower respiratory tract infections in primary care

The objective of this study was to assess compliance with a 10-day treatment of antibiotics or placebo once-daily (OD) and three-times-daily (TD) for lower respiratory tract infections (LRTIs) using electronic monitoring, and to evaluate whether compliance depends on time since the start of treatment and weekday. Taking compliance, timing compliance, correct dosing compliance and mean interdose intervals were assessed using data from 155 LRTI patients who received either a 10-day treatment of amoxicillin TD and placebo OD or roxithromycin OD and placebo TD using a double-dummy technique. Compliance was assessed by electronic monitoring. Taking compliance was 98.0% for the OD regimen and 91.0% for the TD regimen. Correct dosing was 98.1% for the OD regimen and 91.1% for the TD regimen and timing compliance was 48.2% and 10.9%, respectively. The mean interdose interval before the first daily dose for the TD group was particularly prolonged to >13h. Correct dosing over time showed fewer patients with correct dosing compliance, reaching a low of 79% for the TD group towards the end of the 10-day treatment. Compliance was not influenced by weekday. This study adds important information to the limited evidence on compliance with antibiotics for LRTI, one of the most common reasons for consultation in primary care. Taking compliance was high for both regimens, yet timing compliance was poor. The prolonged mean interdose intervals provide striking new insights into understanding non-compliance with more-than-once-daily regimens. These findings require consideration when exploring ways to improve future compliance in short-term antibiotic treatment for respiratory tract infections.

Effects of an enhanced secondary prevention program for patients with heart disease: a prospective randomized trial

BACKGROUND

Secondary prevention medications in cardiac patients improve outcomes. However, prescription rates for these drugs and long-term adherence are suboptimal.

OBJECTIVE

To determine whether an enhanced secondary prevention program improves outcomes.

METHODS

Hospitalized patients with indications for secondary prevention medications were randomly assigned to either usual care or an intervention arm, in which an intensive program was used to optimize prescription rates and long-term adherence. Follow-up was 19 months.

RESULTS

A total of 2643 patients were randomly assigned in the study; 1342 patients were assigned to usual care and 1301 patients were assigned to the intervention arm. Prescription rates were near optimal except for lipid-lowering medications. Rehospitalization rates per 100 patients were 136.2 and 132.6 over 19 months in the usual care and intervention groups, respectively (P=0.59). Total days in hospital per patient were similar (10.9 days in the usual care group versus 10.2 days in the intervention group; P not significant). Crude mortality was 6.2% and 5.5% in the usual care and intervention groups, respectively, with no significant difference (P=0.15) in overall survival. Post hoc analysis suggested that after the study team became experienced, days in hospital per patient were reduced by the program (11.1+/-0.91 and 8.9+/-0.61 in the usual care and intervention groups, respectively; P<0.05).

CONCLUSIONS

The intervention program failed to improve outcomes in the present study. One explanation for these results is the near optimal physician compliance with guidelines in both groups. It is also possible that a substantial learning curve for the staff was involved, as suggested by the reduction in total days in hospital in the intervention patients during the second part of the study.

Adherence to HAART therapy measured by electronic monitoring in newly diagnosed HIV patients in Botswana

Aims

This pilot study was designed to evaluate the feasibility and benefits of electronic adherence monitoring of antiretroviral medications in HIV patients who recently started Highly Active Anti Retroviral Therapy (HAART) in Francistown, Botswana and to compare this with self-reporting.

Methods

Dosing histories were compiled electronically using Micro Electro Mechanical Systems (MEMS) monitors to evaluate adherence to prescribed therapies. Thirty patients enrolled in the antiretroviral treatment program were monitored over 6 weeks. These patients were all antiretroviral (ARV) naïve. After each visit (mean three times) to the pharmacy, the data compiled by the monitors were downloaded. Electronic monitoring of adherence was compared to patient self-reports of adherence.

Results

The mean individual medication adherence level measured with the electronic device was 85% (range 21–100%). The mean adherence level measured by means of self-reporting was 98% (range 70–100%). Medication prescribed on a once-a-day dose base was associated with a higher adherence level (97.9% for efavirenz) compared with a twice-a-day regimen (88.4% for Lamivudine/Zidovudine).

Conclusions

It is feasible to assess treatment adherence of patients living in a low resource setting on HAART by using electronic monitors. Adherence, even in the early stages of treatment, appears to be insufficient in some patients and may be below the level required for continuous inhibition of viral replication. This approach may lead to improved targeting of counselling about their medication intake of such patients in order to prevent occurrence of resistant viral strains due to inadequate inhibition of viral replication. In this pilot study a significant difference between the data recorded through the electronic monitors and those provided by self-reporting was observed.

A randomized controlled psycho-education intervention trial: Improving psychological readiness for successful HIV medication adherence and reducing depression before initiating HAART

The purpose of this study was to evaluate a novel psycho-educational intervention intended to increase patients' medication preparedness and treatment adherence skills before initiating highly active antiretroviral therapy (HAART). Sixty-three HIV-positive patients not currently on antiretroviral therapy participated in a randomized controlled trial of a standardized, four-session psycho-educational intervention (Supportive Therapy for Adherence to Antiretroviral Treatment; STAART). Session topics included learning techniques to increase medication adherence and learning effective strategies to cope with stress and depression. Patients completed psychological questionnaires assessing psychological readiness to initiate HAART and depressed mood. They completed both measures at study baseline and at four-weeks post-baseline. After controlling for baseline medication readiness scores, intervention patients (n = 30) reported significantly higher mean medication readiness following the STAART intervention (four-weeks post-baseline) (27.3+/-6.9) compared to controls (n = 33; 24.6+/-9.9; p < 0.05). Among depressed patients (n = 27), those receiving the intervention (n = 15) reported significantly lower mean depression scores at four-weeks post-baseline (22.5+/-12.9) compared to controls (n = 12; 27+/-9.9; p < 0.05). The STAART intervention enhanced HIV treatment readiness by better preparing patients prior to initiating HAART. It was also beneficial for reducing depressive symptoms in depressed, HIV-positive patients.

Cost effectiveness of an adherence-improving programme in hypertensive patients

BACKGROUND

Non-adherence to antihypertensive drugs is high, and the economic consequences of non-adherence may be substantial. The Medication Events Monitoring System (MEMS), which is a method to improve adherence, has been shown to be a useful tool for the management of adherence problems.

OBJECTIVE

To assess the cost effectiveness of the MEMS compared with usual care in a population of hypertensive patients with poor adherence. The MEMS programme consisted of provision of containers fitted with electronic caps together with adherence training if indicated.

METHODS

In a randomised controlled trial, 164 hypertensive patients in the experimental strategy and 89 patients in the usual care strategy were followed for 5 months. Patients who had a systolic blood pressure (SBP) > or = 160 mm Hg and/or diastolic BP (DBP) > or = 95 mm Hg despite the use of antihypertensive drugs were eligible. Patients were recruited by a GP, and treatment took place in general practice. In the experimental strategy, electronic monitoring of the intake of antihypertensive drugs was introduced without change of medication. Unsatisfactory adherence was defined as < 85% of days with the number of doses taken as prescribed. In the usual care strategy, antihypertensive treatment was intensified by the addition or change of antihypertensive drugs, if necessary, without provision of an electronic monitor. Outcome parameters included the proportion of patients with normalised blood pressure (NBP) at 5 months and QALYs. Costs were quantified from the healthcare and societal perspective. Non-parametric bootstrap simulations were performed to quantify the uncertainty around the mean estimates and cost-effectiveness acceptability curves were presented. In addition, a number of univariate sensitivity analyses were performed on deterministic variables.

RESULTS

At 5 months, 3.1% (95% UI [uncertainty interval] -9.7%, +15.8%) more patients had NBP, and 0.003 (95% UI -0.005, +0.010) more QALYs were generated in the experimental strategy. A statistically significant lower percentage of patients had a dose escalation in the experimental strategy. Irrespective of the ceiling ratio for cost effectiveness, the cost-effectiveness probability was between 75% and 80% for the analysis from the healthcare perspective using proportion of patients with NBP as the outcome parameter. For the analysis from the societal perspective using QALYs as the outcome parameter, this probability was between 45% and 51%.

CONCLUSION

For a time horizon of 5 months, a difference in both cost and effect could not be detected between an adherence-improving programme compared with usual care for hypertensive patients. The probability that the adherence-improving programme is cost effective is at best moderate. Moreover, the cost-effectiveness result is surrounded with considerable uncertainty and large-scale implementation warrants additional research into the economic consequences of this intervention. Patients may benefit from the use of a MEMS monitor in situations where BP targets are not reached because of suspected non-adherence and both patient and GP are reluctant to increase the dose or number of antihypertensive drugs.

Compliance-guided therapy : a new insight into the potential role of clinical pharmacologists

BACKGROUND AND OBJECTIVE

In the field of drug noncompliance, we investigated an original approach that could give the prescribing physician, in collaboration with a clinical pharmacologist, an active role. The aim here is for the prescribing physician to take compliance into account so as to provide an optimised prescription (choice of molecule prescribed and its rhythm of administration) adapted to each patient. The example considered is that of oral anticoagulant treatment prescribed long-term.

METHODS

In order to investigate the choice of the best molecule and treatment regimen for a given noncompliance pattern, we performed an in silico study with two oral anticoagulant agents, warfarin and acenocoumarol, each taken in one or two daily doses. Three linked models were used: the first model generated specific noncompliance patterns, the second model described the pharmacokinetics of oral anticoagulant agents and the third model summarised the pharmacokinetic-pharmacodynamic relations.

RESULTS

Considering different patterns of noncompliance (including timing errors in drug intake and the phenomenon of drug holidays) and comparing warfarin with acenocoumarol, we identified different situations in which one agent (prescribed once or twice daily) could clearly minimise both the thromboembolic and haemorrhagic risks. However, for some specific noncompliance patterns, the choice of the optimal therapy should also be guided by the basal individual thromboembolic and haemorrhagic risks.

CONCLUSION

Individualisation of drug therapy involves both drug dose and drug choice. In addition to the classical approach (i.e. drug level measurements, enzyme assays and even genetic sequence data), our study suggests that compliance-guided therapy may represent a potential, evolving way for the individualisation of prescriptions.

All that glisters is not gold: a comparison of electronic monitoring versus filled prescriptions--an observational study

BACKGROUND

Poor compliance with antihypertensive medication is assumed to be an important reason for unsatisfactory control of blood pressure. Poor compliance is difficult to detect. Each method of measuring compliance has its own strengths and weaknesses. The aim of the present study was to compare patient compliance with antihypertensive drugs as measured by two methods, electronic monitoring versus refill compliance.

METHODS

161 patients with a diagnosis of hypertension for at least a year prior to inclusion, and inadequate blood pressure control (systolic blood pressure > or = 160 mmHg and/or diastolic blood pressure > or = 95 mmHg) despite the use of antihypertensive drugs, were included. Patients' pharmacy records from 12 months prior to inclusion were obtained. Refill compliance was calculated as the number of days for which the pills were prescribed divided by the total number of days in this period. After inclusion compliance was measured with an electronic monitor that records time and date of each opening of the pillbox. Agreement between both compliance measures was calculated using Spearman's correlation coefficient and Cohen's kappa coefficient.

RESULTS

There was very little agreement between the two measures. Whereas refill compliance showed a large range of values, compliance as measured by electronic monitoring was high in almost all patients with estimates between 90% and 100%. Cohen's kappa coefficient was 0.005.

CONCLUSION

While electronic monitoring is often considered to be the gold standard for compliance measurements, our results suggest that a short-term electronic monitoring period with the patient being aware of electronic monitoring is probably insufficient to obtain valid compliance data. We conclude that there is a strong need for more studies that explore the effect of electronic monitoring on patient's compliance.

Prevalence of prednisolone (non)compliance in adult liver transplant recipients

Limited evidence is available concerning (non)compliance with the immunosuppressive regimen in adult liver transplant recipients. In our study we prospectively assessed prednisolone (non)compliance in 108 adult liver transplant recipients using electronic event monitoring (EEM) in an outpatient setting. The EEM is a pill bottle fitted with a cap containing a microelectronic circuit that registers date and time of bottle openings and closings. Median taking compliance was 100% (range 60-105%), median dosing compliance was 99% (range 58-100%); median timing compliance (TIC) was 94% (42-100%). A drug holiday (DH) of > or =48 h was found in 39% of the patients of > or =72 h in 16% of the patients. Using EEM in liver transplant recipients, we found an overall high level of compliance for prednisolone, except that TIC was low in about one third of the patients. Age below 40 years was found a significant risk factor for decreased TIC and for DHs of > or =48 h.

Assessing medication adherence in the elderly: which tools to use in clinical practice?

Adherence to prescribed medication regimens is difficult for all patients and particularly challenging for the elderly. Medication adherence demands a working relationship between a patient or caregiver and prescriber that values open, honest discussion about medications, i.e. the administration schedule, intended benefits, adverse effects and costs. Although nonadherence to medications may be common among the elderly, fundamental reasons leading to nonadherence vary among patients. Demographic characteristics may help to identify elderly patients who are at risk for nonadherence. Inadequate or marginal health literacy among the elderly is common and warrants assessment. The number of co-morbid conditions and presence of cognitive, vision and/or hearing impairment may predispose the elderly to nonadherence. Similarly, medications themselves may contribute to nonadherence secondary to adverse effects or costs. Especially worrisome is nonadherence to 'less forgiving' drugs that, when missed, may lead to an adverse event (e.g. withdrawal symptoms) or disease exacerbation. Traditional methods for assessing medication adherence are unreliable. Direct questioning at the patient interview may not provide accurate assessments, especially if closed-ended, judgmental questions are posed. Prescription refill records and pill counts often overestimate true adherence rates. However, if elders are asked to describe how they take their medicines (using the Drug Regimen Unassisted Grading Scale or MedTake test tools), adherence problems can be identified in a non-threatening manner. Medication nonadherence should be suspected in elders who experience a decline in functional abilities. Predictors of medication nonadherence include specific disease states, such as cardiovascular diseases and depression. Technological aids to assessing medication adherence are available, but their utility is, thus far, primarily limited to a few research studies. These computerised devices, which assess adherence to oral and inhaled medications, may offer insight into difficult medication management problems. The most practical method of medication adherence assessment for most elderly patients may be through patient or caregiver interview using open-ended, non-threatening and non-judgmental questions.

Initializing concordance in frail elderly patients via a medicines organizer

BACKGROUND

Concordance, which involves prescribing with rather than for patients, should result in less drug wastage (non-use), but is proving hard to put into practice. One possible way of easing elderly people and prescribers toward concordance is to use a medicines organizer (MO).

OBJECTIVE

To document medication wastage, using a pharmacy-prepared reusable MO, and explore, using a qualitative approach, use of this information on communication of individuals' drug regimens.

METHODS

Sixty-two sheltered housing residents, aged > or =60 years, participated in an exploratory controlled, matched study. The intervention group received medication in the MO, and the control group continued with standard packaging. Community pharmacists recorded details of wasted drugs returned during the 3-month study and, for the intervention group, 6, 9, and 12 months after the study. Medicines management data were collected from participants. Qualitative interviews were conducted with a sample of general practitioners (GPs) and community pharmacists to explore views on the role of the MO.

RESULTS

Intervention group wastage was reduced from 18.1% (prestudy) to 1% at 12 months. No data on wastage were collected for the control group after the prestudy assessment. Sixty-one percent more prescription changes, including significant decreases in the number of prescribed drugs and dosages, were reported for the intervention group. GPs and pharmacists reported improvements in communication concerning medication-related dialog.

CONCLUSIONS

This small exploratory study has shown that a pharmacy-prepared reusable MO provided visual, objective insights into medication wastage. This resulted in improved communication of drug needs and reduced wastage-the foundation for concordance.

Electronic pill-boxes in the evaluation of oral hypoglycemic agent compliance

OBJECTIVE

To compare compliance in type 2 diabetic patients treated with glimepiride once daily or glibenclamide twice to three times daily.

METHODS

Poorly controlled type 2 diabetic patients aged 35-65 years were randomized to glimepiride 1 mg once daily or to glibenclamide 1.25 mg twice daily. During initial titration, doses ranged from 1 to 6 mg once daily (glimepiride) and from 1.25 mg twice daily to 5 mg 3 times daily (glibenclamide) to achieve fasting blood glucose < 126 mg/dL. The final titration phase doses were continued during the maintenance phase. Both treatments were packed in electronic pill-boxes fitted with a microprocessor to record dates and times of each opening. Compliance was assessed in terms of mean daily compliance (MDC) and the ratio of days with adequate compliance (DAC). Glycemic control was assessed in terms of the adjusted mean final HbA1c, and the incidence of hypoglycemia. Patient satisfaction was evaluated using the Diabetes Treatment Satisfaction Questionnaire.

RESULTS

Compliance over the whole study was generally good, but the MDC was significantly better with glimepiride (87+/-16%) than with glibenclamide (80+/-17%;P < 0.0001). The ratios of DAC for glimepiride and glibenclamide were 87+/-16% and 67+/-24% respectively (P < 0.0001). The adjusted final HbA1c, and the incidence of hypoglycemia were similar in the two groups. Treatment satisfaction on the DTSQc was greater with glimepiride than with glibenclamide (P = 0.0034).

CONCLUSIONS

Patient compliance and treatment satisfaction with once-daily glimepiride were significantly better than with glibenclamide 2 to 3 times daily.

Assessing adherence with toothbrushing instructions using a data logger toothbrush

OBJECTIVES

To evaluate patient compliance with toothbrushing instructions using a data logger and a brushing diary.

METHODS

Dental patients were provided with powered toothbrushes modified to carry electronic data loggers. Demonstration of the most effective way to use the toothbrush was provided with instructions to brush for 2 minutes morning and evening. Data logger brushes were supplied for two episodes of 8 weeks. Brushing time was also recorded in a diary during episode 1.

RESULTS

Data from 14 brushes (2,287 recordings) were used to evaluate compliance in episode 1 Nine brushes (1,526 recordings) were used in episode 2 A total of 2,333 brushing events were reported manually in the diaries. Data logger records during episode 1 showed that only 34% of events were compliant with the instruction of a 2 minute brushing time, 20% were partially compliant (within +/-30s of 2 minutes), and 46% of events were non-compliant (>30s from 2 minutes). The respective proportions for episode 2 were 24%, 24% and 52%. Diary data reported 58% of events as compliant with 42% non-compliant.

CONCLUSIONS

Manually completed brushing diaries do not provide an accurate reflection of subjects' compliance with toothbrushing instructions.

Facts and fiction of poor compliance as a cause of inadequate blood pressure control

OBJECTIVE

(i) To obtain an overview of measured compliance with antihypertensive medication; (ii) to explore sources of variation in measured compliance percentages between studies; and (iii) to investigate whether studies can establish a relationship between compliance and achieved blood pressure.

STUDY SELECTION

MEDLINE, PubMed and EMBASE databases were searched for studies, published between 1985 and 2003, in which patient compliance with antihypertensive medication was measured with electronic monitors.

DATA EXTRACTION

A standard form was used to extract relevant data from the included articles. Two investigators extracted all data independently.

RESULTS

Thirty studies were identified. The studies included were highly varied in their methods used to quantify compliance. Taking compliance and/or correct dosing were used in 20 studies. Mean taking compliance for a once-daily regimen was 94.0 +/- 4.4% and 88.2 +/- 6.5% for a twice-daily regimen. Mean correct dosing was 85.0 +/- 8.7% for a once-daily regimen and 75.3 +/- 6.5% for a twice-daily regimen. Proportions of patients with taking compliance or correct dosing </= 80% were provided by only five studies and ranged between 9 and 37%. Studies with a monitoring period exceeding 6 months showed a distinct decrease in compliance over time. Studies on the association between achieved blood pressure and compliance gave inconsistent results.

CONCLUSIONS

Although poor compliance is assumed to be an important explanation for inadequate blood pressure control, any convincing empirical evidence to support this hypothesis is currently lacking. The relationship between patient compliance and blood pressure control has not yet been properly established.

Lipid-lowering therapy: strategies for improving compliance

Lowering cholesterol levels is a primary approach for reducing the risk of coronary heart disease (CHD), yet patients rarely achieve the lipid targets recommended by international guidelines. Although high rates of compliance and achievement of lipid targets have been reported in clinical trials, this situation is infrequently reproduced in regular practice. This sub-optimal lipid management has clinical consequences as patients will not gain the full benefit of treatment. Poor compliance with therapeutic lifestyle changes and/or lipid-lowering agents is thought to contribute to the failure of patients in clinical practice to achieve lipid targets, and therefore this problem needs to be addressed. Several approaches may be used to improve compliance, including the prescription of efficacious, well-tolerated agents, educating patients about the necessity of therapy, and regular follow-up to monitor compliance and achievement of goals. However, educating patients to promote compliant behaviour can be time-consuming and therefore the support of other health-care workers, where available, can prove invaluable. Compliance initiatives using educational materials, access to helplines and regular telephone contact with a qualified health-care worker may also improve adherence with therapy. Further studies into the causes of poor compliance and methods of improving adherence with lipid-lowering agents are required.

Measuring adherence in a hypertension clinical trial

BACKGROUND

Non-adherence in hypertension is a global problem and promoting adherence is necessary to decrease cardiovascular mortality.

AIMS

The purpose of this paper is to examine the measurement of adherence to medication taking in hypertensive patients. Adherence was evaluated primarily by means of MEMS (Medication Event Monitoring System, Aprex Corporation, Fremont, California) an electronic system that records the date and time of opening of the study medication container. Additional measurements such as change in urinary potassium level, capsule count, client self report and physician estimate of adherence were recorded.

METHODS

A randomised clinical trial was used to assign patients to receive the study medication (potassium) or placebo. Descriptive statistics were used to answer the research questions. Frequency and percentage of responses to different measures of adherence were carried out as well as correlation between the measures.

RESULTS

One hundred and seven subjects between the ages of 26 and 80 participated in the clinical trial. The results showed that adherence measures varied with lowest adherence from two items of self-report related to forgetfulness (46 and 55%) and stringent electronic monitoring with the MEMS (58%) to percentages in the 80-90 range for other self-report items and the general adherence scale. Electronic monitoring correlated best with capsule count at visit 5. Implications for health care providers are discussed.

Monitoring compliance in resistant hypertension: an important step in patient management

Poor compliance with antihypertensive drug regimens is one recognized cause of inadequate blood pressure control. Compliance is difficult to measure, so poor adherence to treatment remains largely undiagnosed in clinical practice. When the therapeutic response to a drug is not the one expected, it is a major challenge for many physicians to decide whether the patient is a non-responder or a non-complier. Poor compliance is therefore often incorrectly interpreted as a lack of response to treatment. Not detecting non-compliance can lead to the wrong measures being taken. Electronic monitoring of compliance provides important longitudinal information about drug-intake behaviour that cannot be obtained in the clinic. Such monitoring can improve both compliance and blood pressure control, and help physicians to make more rational therapeutic decisions. A reliable assessment of compliance could have a great impact on medical costs by preventing unnecessary investigations or dose adaptations in patients who are not taking their drugs adequately, or potentially reducing the number of hospitalizations. Side-effects and lack of effectiveness are two frequent causes of poor compliance. The right choice of antihypertensive drug can therefore contribute to compliance. In this respect, it is important to find a drug regimen that is effective, long-acting and well tolerated. Long-acting antihypertensive drugs that provide good blood pressure control beyond the 24-h dosing period should perhaps be considered as drugs of choice in non-compliant patients with hypertension because they help to prevent the consequences of occasional drug omissions.

Compliance with saliva sampling protocols: electronic monitoring reveals invalid cortisol daytime profiles in noncompliant subjects

OBJECTIVE

Ambulatory saliva collections for subsequent analysis of free cortisol levels are now frequently applied to measure adrenocortical activity in healthy subjects and patient populations. Despite the prime importance of accurate timing of saliva collection outside the laboratory, no data are available on the compliance of study participants following a given sampling protocol. This study investigated how accurately subjects adhered to the instructions to collect six saliva samples throughout 1 day.

METHODS

Subjects were instructed to collect six saliva samples throughout 1 day (directly after awakening, 30 minutes after awakening, 11 AM, 3 PM, 8 PM, 10 PM). Objective compliance was measured using an electronic monitoring device given to the subjects either with ("informed" N = 23) or without ("noninformed" N = 24) their knowledge of the nature of the device. Data on subjective compliance were obtained by self-report.

RESULTS

Thirty-one subjects (74%) were found to comply with the sampling instructions, and 11 (26%) failed at least once to obtain the saliva sample at the correct time of day. Nine of the 11 noncompliant subjects (82%) had two or more noncompliant samples. Fifty-five percent (6 of 11) of the noncompliant subjects took sample 2 outside the sampling window. The circadian cortisol profile differed significantly between compliant and noncompliant subjects (F = 7.98, p =.007). The most important effect of compliance was seen in the rise of cortisol at awakening. Compliant subjects showed a robust increase, whereas noncompliant individuals had only minimal changes from baseline at 30 minutes after awakening (t = 2.89, p =.007). Thus the steepness of the circadian cortisol decline was greater for compliant subjects (t = 2.10, p =.043). Furthermore, the informed group adhered more closely to the sampling protocol than the noninformed subjects (p =.001). Self-reported compliance also differed significantly between study groups (p =.03). In the noninformed group, self-reported sampling accuracy was significantly higher than objectively measured compliance (p =.03); the two measures were similar in the informed group (p = NS).

CONCLUSIONS

A significant number of subjects did not obtain saliva samples reliably in an ambulatory setting. This can partially invalidate the cortisol results and mask potential differences between subject groups of interest. We therefore recommend the use of electronic monitoring devices or other suitable methods and that study participants be informed about the device when ambulatory saliva collection is performed.

Adherence to angiotensin-converting enzyme inhibitor therapy for heart failure

This study examined adherence to angiotensin-converting enzyme inhibitor therapy among 171 heart failure clinic patients. Adherence was monitored over a 3-month period with an electronic event monitor housed in a medication bottle cap, which recorded the date and time the cap was opened and closed. The average percentage of days that the prescribed number of doses (regimen adherence) was taken over the observation period was 84%. Seventy-one percent of patients showed 85%-100% adherence with their daily regimen; 19% exhibited less than 70% adherence. The overall high rates of adherence to angiotensin-converting enzyme inhibitor therapy observed among heart failure clinic patients is consistent with research that shows improved outcomes for patients managed in heart failure clinics. Electronic medication monitoring can be useful in identifying a substantial fraction of patients who are poorly adherent so that interventions to improve adherence can be targeted toward them. Additional research is needed to develop and test adherence-enhancing interventions.

Non-compliance and its management in teenagers

Renal transplantation restores a patient's endogenous renal function. The benefits of this restoration are especially dramatic in children. However, transplantation is a complex and expensive therapy which, when successful, requires consistent adherence to a complex regimen of drug therapy and clinical follow-up. Transplant medications need to be taken for a lifetime. Whilst very effective, immunosuppressant medications can also cause a number of side-effects and require daily multi-dose schedules. Teenagers, in particular, have problems adhering to these regimens and weighing the consequences of non-compliance. Approaches to improving teenagers' compliance must address both the special circumstances of adolescence and the broad, general problem of post-transplant non-compliance.

A clinical evaluation of a novel data logger to determine compliance with the use of powered toothbrushes

OBJECTIVES

The primary objective of this study was to evaluate the viability of an electronic data logger to record the brushing episodes of patients receiving standardised oral hygiene instructions. The secondary objective was to estimate the compliance of a group of patients diagnosed with chronic periodontal disease with brushing time instructions for the daily use of a powered toothbrush over a 2-month period.

MATERIAL AND METHODS

17 modified Philips Jordan Sensiflex 2000 powered toothbrushes (PTBs) were provided to patients (32-67 years) attending for non-surgical management of chronic periodontal disease. The PTBs incorporated an electronic data logger which recorded, for each individual brushing event: the length of time the brush was used (identifying the brushing speed setting); the maximum, minimum and average current during operation; and the time spent charging in between two consecutive brushing events. The patients were given detailed instructions with the PTB and were told to use it for 2 min each morning and 2 min in the evening. The patients returned for non-surgical management over two visits prior to reinforcement of the oral hygiene instructions 1 month after PTB allocation. Subjects were asked to complete a simple brushing diary to record their use of the toothbrush on a daily basis. After 2 months of using the PTBs at home, the brushes and diaries were collected and the data downloaded from the data loggers.

RESULTS

Of the 17 data loggers allocated, two recorded no information and two subjects did not return for the follow-up appointments. The data from the remaining 13 data loggers were evaluated for level of compliance. An event of brushing between 120 and 130 s was considered to be compliant, one of between 90 and 120 or 130-150 s was partially compliant and brushing for < 90 s or > 150 s was recorded as non-compliant. Percentage compliance for all the events (2087 recordings) was 34%, partial- and non-compliance were calculated as: 18%; 48% of events, respectively.

CONCLUSION

This data logger has provided previously unrecorded data on the brushing times for a group of patients using a powered toothbrush at home during non-surgical management of chronic periodontal disease. The data suggested that almost half (48%) of the brushing events recorded by the data loggers were greater than 30 s above or below the instructed brushing time.

A review of the literature on the economics of noncompliance. Room for methodological improvement

Therapeutic noncompliance is a major issue in health care, having important negative consequences for clinical outcome as well as for health-care costs. This paper reviews the literature on the economics of therapeutic noncompliance, identifies methodological shortcomings and formulates recommendations for future economic research in this area. Medication noncompliance was explored more extensively, as the majority of articles dealt exclusively with this aspect of therapy. Eighteen studies were assessed according to their definition and measurement of medication noncompliance, study design, and identification and valuation of costs and outcomes. Very diverse designs and often invalid methods for calculating costs were found. Medication noncompliance is often ill-defined and measured in an inaccurate way. The economic consequences of therapeutic noncompliance have rarely been investigated according to the standard principles of good economic evaluation. Six studies examined both costs and consequences of noncompliance in a cost-outcome description or a cost-benefits, cost-effectiveness or cost-utility analysis. Eight studies dealt with the economic value of compliance-enhancing interventions. In general, studies on the economic consequences of noncompliance lack methodological rigour and fail to meet qualitative standards. There is a clear need for more and better research on the impact of noncompliance, on the cost-effectiveness of interventions and the potential of compliance-enhancing interventions to improve patient outcomes and/or reduce health-care costs.

Some economic consequences of noncompliance

The twin problems of poor compliance and poor persistence with prescribed antihypertensive drug regimens appear to be responsible for much of the huge shortfall in the proportion of hypertensives whose treatment brings their blood pressure down to satisfactory levels. A further problem is the confounding of nonresponse and poor compliance in patients with "drug-resistant hypertension," in that about half of such patients are poor compliers, whose response to simple regimens usually proves satisfactory once their compliance with prescribed regimens is corrected. Electronic means for compiling ambulatory patients' drug dosing histories have now made it both technically and economically feasible to distinguish clearly between noncompliers and nonresponders, which clinical judgment cannot do because it is no better at making this crucial distinction than a coin toss. With the advent of reliable, economical measurements of patient compliance with prescribed drug dosing regimens, we can probably eliminate most of the compliance problems. The problem awaiting us after that is poor persistence with prescribed regimens for antihypertensive and other cardiovascular medicines that are meant for long-term or life-long use. A recent study has shown that median persistence with fully reimbursed drugs of the statin class is only 6 months, which is about one fortieth of the length it should be to realize full benefits of such therapy.

Adherence to treatment regimen in depressed patients treated with amitriptyline or fluoxetine

OBJECTIVE

Non-compliance presents a constant challenge to effective therapy. Many studies only investigate early treatment discontinuation and not other measures like adherence to treatment regimen. We compared adherence in depressed patients using either a selective serotonin reuptake inhibitor (fluoxetine) or a tricyclic antidepressant (amitriptyline), and examined its clinical relevance through adverse events, drop-out rates, and outcome. Adherence was measured electronically with the MEMS (Medication Event Monitoring System).

DESIGN

Nine-week double blind, randomized controlled trial.

SETTING

Ambulatory psychiatric care.

PATIENTS

Random sample of 66 depressed (DSM-III-R criteria) patients.

INTERVENTION

Fluoxetine 20 mg or amitriptyline 150 mg.

MAIN OUTCOME MEASURES

Time course of adherence and its relation to severe adverse events, drop-outs and outcome.

RESULTS

Non-adherence to the treatment regimen occurred frequently in both treatment groups: 31% of patients had at least one 3-day drug holiday, and 34% of patients had at least one episode of three pills in a 24-h period. Over-consumption occurred more frequently during the early phases of treatment while under-consumption occurred more frequently during the later phases. Patients on amitriptyline (P=0.03) and patients with a higher pill intake (P=0.01) experienced more severe adverse events. Patients on amitriptyline (P=0.009) and patients with a lower adherence to the treatment regimen (P=0.004) discontinued from treatment more frequently. The final Hamilton score was significantly predicted by a longer duration of treatment and by a better adherence, but only in amitriptyline users.

CONCLUSIONS

Non-adherence to the treatment regimen has important clinical consequences. Pharmacodynamics and human behavior predict risk for severe adverse events and drop-outs. Moreover, in amitriptyline users but not in fluoxetine users, better adherence predicts a better outcome.

A systematic review of the associations between dose regimens and medication compliance

BACKGROUND

Previous reviews of the literature on medication compliance have confirmed the inverse relationship between number of daily doses and rate of compliance. However, compliance in most of these studies was based on patient self-report, blood-level monitoring, prescription refills, or pill count data, none of which are as accurate as electronic monitoring (EM).

OBJECTIVE

In this paper, we review studies in which compliance was measured with an EM device to determine the associations between dose frequency and medication compliance.

METHODS

Articles included in this review were identified through literature searches of MEDLINE, PsychInfo, HealthStar, Health & Psychosocial Instruments, and the Cochrane Library using the search terms patient compliance, patient adherence, electronic monitoring, and MEMS (medication event monitoring systems). The review was limited to studies reporting compliance measured by EM devices, the most accurate compliance assessment method to date. Because EM was introduced only in 1986, the literature search was restricted to the years 1986 to 2000. In the identified studies, data were pooled to calculate mean compliance with once-daily, twice-daily, 3-times-daily, and 4-times-daily dosing regimens. Because of heterogeneity in definitions of compliance, 2 major categories of compliance rates were defined: dose-taking (taking the prescribed number of pills each day) and dose-timing (taking pills within the prescribed time frame).

RESULTS

A total of 76 studies were identified. Mean dose-taking compliance was 71% +/- 17% (range, 34%-97%) and declined as the number of daily doses increased: 1 dose = 79% +/- 14%, 2 doses = 69% +/- 15%, 3 doses = 65% +/- 16%, 4 doses = 51% +/- 20% (P < 0.001 among dose schedules). Compliance was significantly higher for once-daily versus 3-times-daily (P = 0.008), once-daily versus 4-times-daily (P < 0.001), and twice-daily versus 4-times-daily regimens (P = 0.001); however, there were no significant differences in compliance between once-daily and twice-daily regimens or between twice-daily and 3-times-daily regimens. In the subset of 14 studies that reported dose-timing results, mean dose-timing compliance was 59% +/- 24%; more frequent dosing was associated with lower compliance rates.

CONCLUSIONS

A review of studies that measured compliance using EM confirmed that the prescribed number of doses per day is inversely related to compliance. Simpler, less frequent dosing regimens resulted in better compliance across a variety of therapeutic classes.

Relation between insufficient response to antihypertensive treatment and poor compliance with treatment: a prospective case-control study

OBJECTIVES

To prospectively compare compliance with treatment in patients with hypertension responsive to treatment versus patients with treatment resistant hypertension.

DESIGN

Prospective case-control study.

SETTING

Outpatient department in a large city hospital in Switzerland, providing primary, secondary, and tertiary care.

PARTICIPANTS

110 consecutive medical outpatients with hypertension and taking stable treatment with at least two antihypertensive drugs for at least four weeks.

MAIN OUTCOME MEASURES

Treatment compliance assessed with MEMS devices; blood pressure determined by 12 hour daytime ambulatory monitoring (pressure <135/85 mm Hg in patients aged 60 indicated hypertension responsive to treatment).

RESULTS

Complete data were available for 103 patients, of whom 86 took >/=80% of their prescribed doses ("compliant") and 17 took <80% ("non-compliant"). Of the 49 patients with treatment resistant hypertension, 40 (82%) were compliant, while 46 (85%) of the 54 patients responsive to treatment were compliant.

CONCLUSION

Non-compliance with treatment was not more prevalent in patients with treatment resistant hypertension than in treatment responsive patients.

Derivation of adherence metrics from electronic dosing records

Numerous adherence variables have been created from electronic dosing records hindering synthesis of the vast body of adherence research. To elucidate the mathematical foundation for electronic adherence monitoring and to understand how diverse electronic adherence metrics are related to each other and the underlying construct of adherence behavior. Several representative adherence metrics are derived mathematically and their relationship to the underlying consumption (or dosing event) rate analyzed. Data from a 3-month study of 286 individuals on single-drug antihypertensive therapy are then used to empirically study the statistical properties of several of these electronic adherence metrics. As suggested by their common link to the consumption (or dosing event) rate, the analyzed electronic adherence metrics were generally strongly correlated (r <- .6 and > .4). The lowest correlation (r = .15) involved the ratio of the observed number of doses to the recommended number (called average adherence), which tended to emphasize quantity consumed, and the ratio of the observed to maximum mean squared rate deviation (MSRD ratio), which focused more on dose timing. Despite their different formulations, electronic adherence variables are generally closely correlated. Adherence metrics that average the consumption rate over multiple doses (by summing up the number of doses and dividing by the monitored time) may be less sensitive to short-term fluctuations in medication intake. Metrics that are more sensitive to timing variability may thus be preferable when timing as well as quantity of dosing are of interest.

Compliance with tricyclic antidepressants: the value of four different methods of assessment

AIMS

To assess the advantages and disadvantages of four methods for studying compliance with antidepressants: self-report scores, tablet counts, a microprocessor (MEMS) container system and the assay of nordothiepin and dothiepin concentrations in plasma.

METHODS

The techniques were used in 88 patients commencing tricyclic antidepressants in the setting of UK general practice.

RESULTS

The MEMS system proved to be the most informative technique allowing identification of the precise time of container opening, the demonstration of 'drug holidays' and early cessation of therapy. Self-report scores (Morisky) proved a useful screening technique with a sensitivity of 72.2% and specificity of 74.1% for > or = 80% compliance. Although tablet counts were possible in 84 patients (95. 5%) they were unreliable in 19 (21.6%). Blood concentration assays proved the least acceptable method to patients and were possible in only 53 (60.2%). A ratio of nordothiepin:dothiepin > or = 1.1 claimed, by others, to identify noncompliance was only reliable when concentrations were low.

CONCLUSIONS

Both the MEMS system and self-report scores proved useful methods for identifying noncompliant patients in the setting of UK general practice. Although compliance was higher than reported in previous studies with 70 patients (79.5%) completing 6 weeks treatment, general practitioners tended to prescribe subtherapeutic doses.

Compliance to live oral Ty21a typhoid vaccine, and its effect on viability

BACKGROUND

Concerns have been expressed that in travelers the efficacy of the live oral Ty21a typhoid vaccine Vivotif could be lower than reported, maybe due to a lack of compliance. The purpose of this study was to examine the level of compliance with the recommendations regarding dosing, timing of dosing with respect to food intake, and storage.

METHODS

Travelers were randomized into two groups: one received oral information only, and the second, a combination of oral and written information. Four criteria of compliance were applied to travelers: 3 capsules needed to be swallowed (criterion 1) on day 1, 3 and 5 (criterion 2), at least 1 hour before or 2 hours after a meal (criterion 3) and the vaccine had to be kept refrigerated (2-8 degrees C) (criterion 4). Compliance was evaluated using three different methods: a questionnaire, pill counting, and electronic monitoring using the Medication Event Monitoring System (MEMS). Storage conditions were checked by temperature tags, and viability of the vaccine was assessed by culturing the content of remaining capsules.

RESULTS

The data of 115 travelers were analyzed. All the travelers took the 3 capsules. Compliance to all four criteria was complete in 68% of travelers according to the questionnaire, and 53% according to the MEMS (p =.05). Sixty-seven percent of all the doses intervals were of 48 hours +/- 6 hours, 12% being shorter than 36 hours and 7% longer than 60 hours. Eighty-seven travelers (76%) took their capsules on each alternate day. The method of information had no significant impact on compliance. Forty-two percent of tags showed exposure to temperature over 10 degrees C for more than 24 hours. Yet, no difference could be found in the viability of the vaccine compared with controls.

CONCLUSIONS

Most travelers take their 3 capsules on alternate days, but many did not follow the other recommendations. Electronic monitoring of compliance provides more accurate results than questionnaires. Emphasis must be put on motivating the travelers to take the vaccine as recommended.