alysis patients, compliance estimates have varied depending on the focus (diet, fluids, medications, or dialysis therapy) and the technique used to estimate ...
Ronita J. Bland, MSW, MEd; Randall R. Cottrell, DEd, CHES; Liliana R. Guyler, PhD, CHES R. Bland is with DaVita Dialysis, and Drs. Cottrell and Guyler are with the University of Cincinnati, Ohio.
Medication Compliance of Hemodialysis Patients and Factors Contributing to Non-Compliance
BACKGROUND: Past studies have shown that non-compliance is a common and increasing problem by those with chronic illnesses, including hemodialysis patients. These studies tended to examine non-compliance as a whole, including diet, fluid restriction, skipping treatments, and medications. Because of the multiple medications that hemodialysis patients need on a daily basis, a study of non-compliance directly related to medication-taking behavior was thought to be important for this population. The purpose of the present study was to determine what factors contributed to the medication non-compliance of hemodialysis patients and to examine the variables of age, race, sex, and educational level as they relate to non-compliance. METHODS: Patients at the Cincinnati DaVita Dialysis Clinic were given questionnaires that asked questions on medication-taking behaviors, patient knowledge, patient attitudes toward medications, and patient compliance. Seventy-seven of 105 patients completed the questionnaire, for a 74% response rate. Data were analyzed using SPSS and SAS software. RESULTS: The results showed that forgetfulness was the main contributing factor reported for medication non-compliance, followed by inconvenience and scheduling problems. Only 11% of this group reported lack of money as a major factor in non-compliance. More highly educated patients had more knowledge about medication compliance than did less highly educated patients. White patients had better attitudes about medication compliance than did African American patients, but no differences were seen between white and African American patients in actual compliance. CONCLUSIONS: A little more than one third of the patients in this study reported that they were not completely compliant with their medications. Because forgetfulness, inconvenience and scheduling problems were the main reasons reported for non-compliance, more emphasis needs to be placed on ways to remind patients to take their medications. More time and effort should be spent helping patients with lower education levels to understand the importance of medication compliance and to help these patients with strategies to be compliant. Differences in medication compliance attitudes need to be examined further in reference to race.
edication compliance has been defined as the extent to which actual drug-taking behavior matches the prescribed regimen.1 The United States Renal Data System (USRDS) reported that patients take an average of 8 prescribed medications, with some receiving as many as 15–20 medications.2 Because of this, compliance is a difficult issue for many patients. Compliance research has varied based on how it has been defined and measured. For hemodialysis patients, compliance estimates have varied depending on the focus (diet, fluids, medications, or dialysis therapy) and the technique used to estimate compliance.
One study reported at least 50% of hemodialysis patients were noncompliant with some part of their treatment regimen.3 Medication compliance has been measured by either subjective measures such as self-report and provider report or by objective measures such as drug levels and pill counts and, less frequently, by electronic monitoring.4 Patient compliance with medication taking could vary from day to day. The best way to determine a patient’s compliance was to examine past behavior.1 Many chronically ill patients took less of their medications than had been prescribed. Cost was thought to be a major cause, especially among those patients with
low incomes, multiple chronic health problems, or no prescription drug coverage. In a previous study, 78% of those who reported underusing medication because of medication costs reported that this occurred at least once a month. The consequences of cost-related medication underuse include increased emergency department visits, psychiatric admissions, and nursing home admission, as well as decreased health status.5 Low income, cultural factors, or a lack of health education and general education contributed to medication non-compliance in poor and racial or ethnic minority populations.6 In another study, predictors May 2008 Dialysis & Transplantation 1
of non-compliance by patients were age, overall patient satisfaction, and medication barriers.7 Patient–physician relationship, literacy level, and applicable theories such as social learning theory, model of change theory and the health belief model have also been examined in relation to non-compliance. The purpose of this study was to determine what factors contributed to medication non-compliance by hemodialysis patients. Further, it examined the variables of age, race, sex, and educational level as they related to non-compliance.
Materials and Methods Criteria for inclusion in this study included being on dialysis for at least 3 months, taking 3 or more prescribed medications, and living outside an institutionalized setting such as a nursing home, group home, or assisted living facility. The participants were patients at the DaVita Winton Rd. Dialysis Center in Cincinnati, Ohio. The University of Cincinnati Institutional Review Board (IRB) reviewed the protocol and granted approval for the study. The instrument used in this study was developed by the researcher. It was divided into 5 sections. The first section contained 3 open-ended questions concerning prescription medication–taking behaviors. The questions asked how many prescription medications were taken each day, how often medications were not taken each day, how often medications were not taken as prescribed in a given day, and how many days of the week medications were not taken as prescribed. The second section of the survey contained 13 questions about medication-taking behaviors and factors related to missing medications. Ten of these 13 questions had 5 possible responses ranging from always to never. The third section of the survey contained 10 Likerttype attitudinal questions related to medication compliance. Each question had 5 possible responses: strongly agree, agree, I don’t know, disagree, and strongly disagree. Points were assigned each response with strongly agree worth 1 point and strongly disagree worth 5 points. The fourth section consisted of 12 questions and was designed to determine the patient’s knowledge about medication-taking behaviors. The answers to the questions were structured in a way 2 Dialysis & Transplantation May 2008
that allowed for a definite true or false answer. The final section of the instrument was the demographic section. Test–retest reliability was established for the instrument with a similar group of patients meeting the same study criteria from another DaVita Clinic. The first time it was given the test/retest reliability score was .769 for the medication-taking behaviors/compliance section, .830 for the knowledge section, and .398 for the attitude section. After reviewing the attitude questions, 2 questions were eliminated, the wording of several questions was simplified, and a second test–retest procedure was conducted. The test–retest correlation on the second administration was .486. At this time the attitude questions were again reviewed. The decision was made to change from a 5-point Likert format to a 4 choices—strongly agree, agree, disagree, and strongly disagree—in order to increase reliability. Further, 3 additional questions were eliminated. A test–retest was conducted for the third time on the 5 remaining attitude questions, and a correlation coefficient of .692 was obtained, which was considered acceptable to continue with the study. The instrument was also reviewed by a panel of experts for content validity. The panel included the medical director and the center director from the dialysis center, 2 social workers, and a nurse who also worked with dialysis patients. The panel reviewed the instrument and provided feedback related to the format of the questions and the type of questions being asked of the participants. The panel also made recommendations for questions not included in the instrument that they thought were relevant to the study. Changes were made in the instrument based on this feedback. The questionnaire was mailed to all eligible patients at the dialysis center. Each mailing included a cover letter that also served as the consent form. The survey and a self-addressed, stamped return envelope were included along with the cover letter. Patients also had the option of returning the survey when they came to the clinic for dialysis instead of mailing it in the envelope. The researcher followed up with patients in the clinic after 2 weeks if they had not returned the survey. The follow-up was conducted in the clinic. Patients were asked if they had received the survey in the mail. If they said they had not received the
original questionnaire, they were asked if they would agree to participate and were given a copy of the survey to complete while at the clinic. If they had received the questionnaire, they were asked if they would consider participating. They were told they could still send the completed survey by mail, or they could be given another copy to complete while at the clinic. If participants indicated the need for assistance in completing the survey, it was read to them by the researcher at the clinic. They also had to sign a consent form before completing the survey. As an incentive to complete the survey, participants were offered either a $5 gas card or a $5 gift card from Kroger Company grocery stores. The gift cards were given to each participant on return of the completed questionnaire. Data collected from the surveys was recorded on a spreadsheet and analyzed using SPSS and SAS software. Statistical tests included the chi-square test, Student's t-test, analysis of variance (ANOVA), and Wilcoxon test. A alpha level of .05 was used throughout the study.
Results Of the 105 eligible dialysis patients, 77 completed the survey, giving a response rate of 74%. See Table I for demographic information on the respondents. Fifty-one of the patients (66.2%) reported taking medication exactly as directed in a 24-hour period. Twenty-six (33.8%) reported being noncompliant. Of the reasons listed for not taking medications as directed, 24 (31.2%) said it was primarily because of forgetfulness. Thirteen respondents(16.9%) indicated scheduling problems prohibited them from taking their medications, whereas 9 (11.7%) said the cost of their prescriptions prohibited them from being compliant. Other reasons included having to wait for authorization at the pharmacy, missed meals, and change in dosage by the doctor. Fewer than 10% of the participants reported these reasons. In relation to cost, 27 (35.1%) said the cost of their medications was always a concern, whereas 31 (40.3%) said they were sometimes concerned about the cost of medications. The remaining participants (19 patients, or 24.6%) said they were never concerned about the cost of medications.
TABLE I. Demographic summary information (n = 77). Variable
Total Number, n (%)
Age Older (ⱖ60 years) Younger (⬍59 years
49 (63.7%) 28 (36.4%)
Living arrangement Lives alone Lives with spouse Lives with other family Lives with friends
26 30 19 2
Sex Male Female
36 (46.8%) 41 (53.2%)
Educational level 12th grade and higher Less than 12th grade
21 (27.3%) 56 (72.7%)
Race African American White Other
49 (63.6% 26 (33.8% 2 (2.6%)
(33.8%) (39.0%) (24.7%) (2.6%)
TABLE II. Knowledge score* by age, race, sex, and education level. Variable
Mean Attitude Score
Age Older Younger
Race African American White
Sex Female Male
Educational level† 12th grade and higher Less than 12th grade
*Possible range of scores: 12–0. †Significant (p ⫽ 0.035).
In the area of compliance, there were no differences found based on race. Both African American and white respondents had about the same rate of compliance. There were also no differences in compliance based on sex. Younger participants and older participants demonstrated similar compliance rates. Educational level was also found to have no effect on compliance. As might be expected, the medication compliance knowledge level of study participants was found to be significantly influenced by education level (see Table II).
these 2 groups was found to be significant (z ⫽ 1.8; p ⫽ 0.035); therefore, the null hypothesis, which stated there would be no difference in knowledge scores based on education level, was rejected. Dialysis patients with higher education levels had more medication compliance knowledge than dialysis patients with lower education levels. No differences were found in knowledge scores based on race, sex, or age. Attitudes toward medication compliance were significantly different based on race (see Table III). White patients had better attitudes about medication compliance than did African American dialysis patients. The mean attitude score for white patients was 17.50, and the mean attitude score for African Americans was 16.37. Because there was not a normal distribution, the nonparametric Wilcoxon test was used to test for significance. The difference between these 2 groups was found to be significant (z ⫽ ⫺1.73; p ⫽ 0.04). When attitude toward medication compliance was examined in relation to sex, age, and educational level, no significant differences were found.
For this study, higher educational level was defined as completion of 12th grade or higher. Lower education level was defined as completion of less than the 12th grade. A medication compliance knowledge score was calculated by adding the number of correct responses on the knowledge section of the questionnaire. The mean score for those with a higher education level was 11.73. The mean score for those with lower education was 11.19. Because there was not a normal distribution, the nonparametric Wilcoxon test was used to test for significance. The difference between
One third of the participants in this study (33.8%) self-reported that they were not completely compliant in taking their prescribed medications, and the most commonly reported reason for not taking medications was forgetfulness, followed by scheduling problems. This certainly implies the need for patients to be fully educated about to the importance of taking medications exactly as directed. Further, patients need help with strategies to effectively schedule and remember when to take their medications. Whatever strategies are currently being use are not sufficient to produce full compliance in one third of the patient population. Cost was not a major factor contributing to non-compliance of participants in this study. However, in past studies, cost was found to be a major factor.8,9 Cost might have been more of an issue if the research had been done later in the year, when Medicare Part D patients would be in the “donut hole,” or gap area, when cost usually is more of a concern. Most patients in this study had insurance coverage for May 2008 Dialysis & Transplantation 3
TABLE III. Attitude score* by age, race, sex, and education level. Variable
Mean Attitude Score
Age Older Younger
Race† African American White
Sex Female Male
Educational level 12th grade and higher Less than 12th grade
Another factor to consider is that race may affect attitudes toward medication compliance, as determined in this study, and therefore different approaches to encourage medication compliance may be needed for different racial and ethnic groups. Cultural differences should always be kept in mind when working with various groups of people. To reduce non-compliance because of forgetfulness, future research needs to be done to test the effectiveness of different methods such as standard pill containers, talking pill containers, peer reminder systems, professional telephone reminder calls, and so forth.
*Possible range of scores: 20–1. †Significant (p ⫽ 0.042).
This article was made possible by a research grant from DaVita. D&T their medications all the time (67.5%), and the rest reported having insurance coverage most of the time (32.5%). Other population groups that do not have insurance coverage and report cost as a major factor need to be closely studied to determine their medication compliance knowledge, attitudes, and behaviors. Overall medication compliance knowledge was high in this group of dialysis patients. Of 12 knowledge questions on compliance, the mean score was 11.59 correct answers. This would imply that a high level of knowledge does not correspond to a high level of medication compliance. It is not known if the patients in this group were unique in their high level of medication knowledge. Further research needs to be done with dialysis patients to determine if there are knowledge gaps among other patient groups and subgroups. In this study, most patients had at least a 12th-grade education. This may have had a positive effect on both overall knowledge level and compliance. In previous studies, having a higher educational level and having more knowledge were associated with better compliance; whereas, less education was generally associated with less knowledge and less compliance.10-12 As might be expected, in this study more highly educated dialysis patients had more knowledge about medication compliance than less educated dialysis patients. Although the difference in medication compliance knowledge scores between the 4 Dialysis & Transplantation May 2008
highly educated (x ⫽ 11.73) and the less educated (x ⫽ 11.19) was statistically significant ( p ⫽ 0.035), the practical implications were minimal as both groups scored high on medication compliance knowledge level. A significant difference in attitudes toward medication compliance was found between African American and white patients in this study. For this population, however, differences in attitudes toward medication compliance were not reflected in medication-taking compliance. Attitudinal differences toward medication compliance should be studied in other populations to determine if these differences persist and if they may affect medication-taking compliance. Future research in this area should focus on using larger and more diverse populations including Asians and Hispanics. Those with less than a high school education among all population groups should also be studied. It is possible these groups may have different compliance rates, different attitudes and different knowledge levels related to medication compliance. The findings in this research can be used by practitioners to help the participants in this study as well as others to develop strategies for remembering to take medications as prescribed. Also, it should be noted that those patients with higher education levels have more knowledge and may not require as much explanation or focus as those patients with lower education levels.
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