A medication monitor and fluorescein technique designed to study medication behaviour

Measurement of adherence to brimonidine therapy for glaucoma using electronic monitoring

PURPOSE

To assess the patient adherence and behavior with brimonidine twice daily (bid) or 3 times daily (tid) in patients used to topical glaucoma medication.

PATIENTS AND METHODS

Seventy-five patients with glaucoma or ocular hypertension were enrolled in a prospective, observational cohort study. Consenting patients were randomly assigned to brimonidine bid or tid and received conventional brimonidine eye drops with attached electronic monitoring devices for 4 weeks. Patients were not explicitly informed on the compliance monitoring.

RESULTS

The study was completed by 67 patients (89%). In 65 patients (97%), at least 1 dosing interval exceeded 24 hours. The mean adherence rates were better in the brimonidine bid group (72 ± 19% vs. 62 ± 16%, P=0.04), although dosing frequency was higher in the tid group (1.9 ± 0.5 vs. 1.4 ± 0.4 per day; P<0.001). On average medication coverage was 70% for the bid group and 67% for the tid group; 19 patients (28%) had a coverage rate above 75%, 42 patients (63%) 50% to 75%, and 6 (9%) below 50%. Patients with normal-tension glaucoma had lower coverage rates than patients with primary open-angle glaucoma and ocular hypertension (P<0.05). Data also showed that on average 20% of the glaucoma medication was wasted owing to inefficient drug delivery by using more than 1 drop per dosing.

CONCLUSIONS

Individual adherence with brimonidine was highly variable and pharmacologically insufficient for more than two-third of the patients. Special attention should be paid to compliance of patients with normal-tension glaucoma. Our findings underline the need to improve individual adherence and drug delivery in topical glaucoma therapy.

Methods in assessing drug compliance

Methods and problems in assessing drug compliance are related to the selection of study sample and observation period as well as to methods used to measure patient behaviour in taking medications. Patients under treatment with a certain drug regimen are different from the patients for whom that regimen was originally prescribed. Medication compliance during short periods of time, such as 1-2 weeks before or after a visit to the clinic, is likely to be different from that found over longer periods of time. Several studies indicate that estimates by clinical staff are no more accurate than chance selections in determining medication compliance. Patient interviews have usually identified 25-50% of noncompliant patients, but interview data on spacing between doses seem to be more accurate. Pill counts are useful in assessing drug compliance, although compliance may sometimes be overestimated. Medication monitors provide more detailed information on patient behaviour in taking medications.

Microprocessor controlled compliance monitor for eye drop medication

BACKGROUND/AIMS

The effectiveness of a self administered eye drop medication can only be assessed if the compliance is known. The authors studied the specificity and sensitivity of a new microprocessor controlled monitoring device.

METHODS

The monitoring system was conducted by an 8 bit microcontroller for data acquisition and storage with sensors measuring applied pressure to the bottle, temperature, and vertical position. 10 devices were mounted under commercial 10 ml eye drops. Test subjects had to note down each application manually. A total of 15 applications each within 3 days was intended.

RESULTS

Manual reports confirmed 15 applications for each of the 10 bottles. The monitoring devices detected a total of 149 events; one was missed; comprising a sensitivity of 99%. Two devices registered three applications, which did not appear in the manual protocols, indicating a specificity of about 98%. Refrigerated bottles were correctly identified. The battery lifetime exceeded 60 days.

CONCLUSION

The new monitoring device demonstrated a high reliability of the collected compliance data. The important, yet often unknown, influence of compliance in patient care and clinical trials shall be illuminated by the new device. This may lead to a better adapted patient care. Studies will profit from a higher credibility and results will be less influenced by non-compliance.

Primary argon laser trabeculoplasty vs pilocarpine. II: Long-term effects on intraocular pressure and facility of outflow. Study design and additional therapy

In a prospective study 82 patients recently diagnosed with simple or capsular glaucoma were randomized to receive primary argon laser trabeculoplasty or pilocarpine treatment. A 2-year follow-up showed a better success rate in the laser group, with less need for additional therapy. The average intraocular pressure and peak pressure was lower and the daytime pressure variation was significantly less in the laser group. The better increase in facility of outflow in the laser group was not statistically significant. In capsular glaucoma, laser treatment resulted in a significantly lower average pressure than with medication. In simple glaucoma the effect was about the same in the two treatment groups. Increase in facility of outflow was significantly better in simple glaucoma than in capsular glaucoma. High initial intraocular pressure gave a significantly lower success rate. Primary argon laser trabeculoplasty as a single glaucoma treatment seems advantageous in comparison to medication with pilocarpine for regulating intraocular pressure.

Treatment compliance in childhood and adolescence

Experience reveals that there is significant noncompliance with self-administered medication, especially in chronic conditions such as cancer. Noncompliance transcends the boundary of disease categories and age group. However, this is most prevalent during the adolescent years when the process of transition from parental dependency to autonomy produces confusion as to who is responsible for administration of medication. Noncompliance can result in the misjudgment of efficacy of a drug or regimen that may necessitate additional tests, alteration of dose, treatment course, and hospitalization. Currently in the United States, a large percentage of pediatric cancer patients are treated according to research protocols. In a research setting, noncompliance can result in erroneous or inconsistent findings, potentially affecting investigational results. With the availability of venous access ports and sophisticated, yet easy-to-operate pumps, increasingly, it is possible to administer parenteral medications at home. This adds a new dimension to the self-administration of medication that previously concerned mainly oral therapy. Various factors concerning the patient, disease, health providers, and treatment characteristics determine how well a given regimen is adhered to. Because a significant number of determinants are involved, it is often not possible, with any degree of certainty, to identify noncompliers or to predict the level of patient adherence to the treatment. Major factors in any successful therapy include the availability of effective medications and compliance with therapy regimen. With the advent of more successful treatments for childhood and adolescent cancer, the compliance factor is gaining greater importance because therapy currently is given with curative, rather than palliative intent. The availability of questionnaires, tests, and devices can help, to some extent, examine the degree of patient compliance. Family and social support, individualized programs, reminders to reduce forgetfulness, personalized needs assessment, and education can reduce noncompliance. Compliance is a complex and multifaceted issue that is still poorly understood and requires further investigation.

Measurement of patient compliance and the interpretation of randomized clinical trials

The aim of this review is to demonstrate why the management of compliance, although not an explicit feature of the rules of Good Clinical Practice, is essential to the successful conduct of clinical trials and in correct interpretation of the results. Methods to measure compliance in randomized clinical trials are also described. The relevant literature was retrieved by a manual search of the Cumulated Index Medicus 1975-1989 and a MEDLINE computer search of publications in 1990 using the Medical Subject Headings "patient compliance" and "clinical trials". All retrieved articles are discussed. Research into patient compliance has stagnated because of the lack of a "gold" standard of measurement. Nevertheless, management of compliance at the different stages of clinical trials is necessary; at trial design, compliance should be taken into account in sample size calculations; during the conduct of a trial, compliance should be monitored in order to safeguard the power of the study; and in interpretation of trial results, compliance data are helpful both in order to avoid erroneous conclusions and to enrich the value of the data. Compliance should be measured in all limbs of randomized trials, including the placebo limb, without breaking trial blinding. A classification of compliance behaviour into six types (complier, partial complier, overuser, erratic user, partial dropout and dropout) is proposed, based on the changes in the risk-benefit ratio produced by non-compliance. The use of deuterium oxide, low dose phenobarbitone (2 mg per day), digoxin (2.2 micrograms per day) and the new electronic monitoring devices are suitable methods for measurement in clinical trials.

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

The utility of a new microprocessor-based method for continuous monitoring of compliance in taking solid medicaments has been evaluated. Medication intake in 31 ambulant patients was assessed in a prospective observational study under the conditions of routine practice. The patients (aged 14-87 y, mean 50 y) were receiving long-term drug treatment for various chronic diseases. There was marked interindividual and intraindividual variation in compliance with different drugs. Deviations from the prescribed dosage regimens were caused by omission of doses (22.7% of prescribed doses) and intake of extra doses (5.6% of prescribed doses). Continuous monitoring revealed that in 19% of the monitoring period no medication was taken, in 13% there was partial intake, and in 8% extra doses were taken. Patient-initiated drug holidays occurred in 50% of patients. They were responsible for 76% of the medication-free time. It is concluded, that continuous compliance monitoring is practicable in ambulatory patients. It provides information about the dynamics of drug intake behaviour that cannot be obtained from medical histories or from clinical or laboratory examination. The information could be used effectively in individual patient care and in clinical drug trials.

Compliance with topical pilocarpine treatment

Using an unobtrusive eyedrop medication monitor, we measured compliance with topical pilocarpine treatment in a sample of 184 patients. The eyedrop monitor recorded electronically the date and time of each pilocarpine administration over a four- to six-week period. The subjects administered a mean +/- S.D. of 76.0% +/- 24.3% of the prescribed pilocarpine doses. Eleven patients (6%) took less than one quarter and 28 patients (15.2%) took less than one half of the prescribed administrations. In contrast, when the subjects were interviewed they reported taking a mean +/- S.D. of 97.1% +/- 5.9% of the prescribed pilocarpine doses. As determined by the monitor, 45 patients (24.5%) had at least one day per month with no administrations of pilocarpine; 56 subjects (30.4%) compressed the doses during the daytime hours, leaving an interval between the night dose and the morning dose the next day of 12 hours or more. The rate of compliance was significantly higher (P less than .0001) in the 24-hour period preceding the return appointment than in the entire observation period.

Memory and medication compliance

Electronic medication monitors were used to study patients' compliance with a three times daily pilocarpine regimen. In addition, standardized tests were used to measure different aspects of patients' memory performance. The 38 mostly elderly patients varied widely in their compliance and memory scores. However, no significant correlation was found between memory and medication compliance. It is concluded that lack of memory may be less important as a cause of non-compliance than is usually believed.

Visual ability and drug regimen: relation to compliance with glaucoma therapy

Compliance with pilocarpine eye drop therapy was studied in relation to different measures of visual ability and different features of the drug regimen. Neither visual ability, nor complexity of the drug regimen nor side effects were significantly related to the patients' compliance with their pilocarpine therapy. Nevertheless, non-compliance was significantly more common among patients who regarded the eye drops as very unpleasant than among patients who did not. This indicates that non-compliance is related to the patient's perception of side effects and/or negative attitudes to the treatment.

Glaucoma patients not compliant with their drug therapy: clinical and behavioural aspects

The pattern of drug self-administration among 15 patients not compliant with their pilocarpine therapy was studied with an electronic medication monitor. Recording the date and the hour every time the medication bottle was opened, the monitor gives detailed information on the medication behaviour. The results indicate different types of medication errors; inadequate spacing of doses during the day with long intervals during the night, frequently missed doses at noon, and long interruptions in the medication, sometimes lasting for several days. Improvement in their compliance was seen in patients who were given instruction and taught to relate their medication to specified events in the day.

Monitoring compliance with pilocarpine therapy

I used a recording medication monitor to obtain objective information on self-medication by date and hour from a group of 82 patients using pilocarpine three times daily to prevent visual loss from glaucoma. Doses meant to be taken during the day were missed more than twice as often as morning or evening doses. Of the missed doses, 272 (54%) were noon doses, but only 98 (19%) were morning doses. Medication compliance may be substantially improved by choosing a drug that needs to be taken less often than three times daily. The number of missed doses per day increases significantly during a 20-day period between clinic visits. This suggested that shorter intervals between clinic visits may improve adherence to the drug regimen prescribed.