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UNIVERSITÄTSKLINIKUM HAMBURG-EPPENDORF

Institut und Poliklinik für Medizinische Psychologie

Direktor: Prof. Dr. med. Dr. phil. Martin Härter

Incomplete Medication Adherence of Chronically Ill Patients in

German Primary Care

Dissertation

zur Erlangung des Grades eines Doktors der Medizin an der Medizinischen Fakultät der Universität Hamburg.

vorgelegt von: Jakob Hüther aus Freiburg im Breisgau

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Angenommen von der

Medizinischen Fakultät der Universität Hamburg am: 27.05.2014

Veröffentlicht mit Genehmigung der

Medizinischen Fakultät der Universität Hamburg.

Prüfungsausschuss, der/die Vorsitzende: Prof. Dr. M. Härter

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CONTENT ARTICLE... 4 SUMMARY... 11 AUTHOR CONTRIBUTION ... 24 ACKNOWLEDGEMENTS ... 25 CURRICULUM VITAE ... 26

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SUMMARY Introduction:

In all healthcare systems prescribing medication represents one of the cornerstones of medical treatment. The purpose of prescribing medications is to improve the patients’ health, including the cure of disease.1-5 The intake of an indicated medication can improve the patients’ clinical outcome not only by treating the primary disease but also by reducing the probability of secondary diseases.6 Overall, patients who take their prescribed medication are less likely to be hospitalized or to die.7-10 In contrast, the complications resulting from patients not taking their medication accordingly are responsible for a big share of the costs in health care systems worldwide.11

A patient’s behavior of following a consensual treatment suggested by a health care provider can be referred to as adherence.12 Incomplete medication

adherence is therefore the occurrence of patients not completely following

recommendations regarding their prescribed medication.

Current international literature suggests an average rate of incomplete adherence by between 26% and 60% of all patients.13-15 The average rate of adherence can vary quite heavily depending on sample and measurement,16,17 especially since there is a lack of a coherent method for the measurement of adherence.18 For Germany, the results range between 35% and 50%.19,20 However, the problem of incomplete adherence in Germany has only been examined by few studies.

Previous studies suggested several associations between incomplete adherence and patient characteristics, including socio-demographic data (low

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(disease,12,22 high complexity of a patient’s medication regimen,16, 23 and low extent of medication information24,25).

This dissertation explores the extent to which a sample of 190 German primary care patients suffering from chronic diseases adhere to their prescribed medication plan and if an association can be detected between the patients’ medication adherence and their socio-demographic and clinical characteristics. Considering current literature, we rated the following health-related variables to be potentially associated with incomplete medication adherence: Sex, age, academic education, employment status, medication information (the level to which patients feel they have received enough information about their prescribed medication), medication complexity (consisting of dosage form, dosage frequency, additional instructions), health related quality of life (HRQoL - consisting of physical and mental health) and the prevalence of specific chronic diseases (hypertension, type-2 diabetes, hyperlipidemia, obesity, malignant tumor).

The analysis was conducted to clarify which of these potential associations should be taken into consideration in clinical care of chronically ill outpatients in German primary care. Once incomplete adherence is understood better, guidelines for screening procedures in clinical routine (e.g. via questionnaires) regarding the adherence of outpatients could be developed and ultimately lead to more favorable clinical outcomes and savings in health care costs.

Methods:

Data were collected in a prospective controlled trial that examined medication complexity, prescription behavior and patient adherence at the

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for the treatment of at least one of the patient’s chronic cardiovascular and/or metabolic conditions. Patients were asked to assess their medication adherence in primary care treatment prior to admission retrospectively utilizing the German version of the Medication Adherence Report Scale (MARS-D).20 Patients were categorized as incompletely adherent if they scored fewer than the maximum 25 points on the MARS-D questionnaire. A high cut-off score as used in this study is recommended, as social desirability bias is to be considered and any report of incomplete adherence should be taken into account.14 To ensure a high sensitivity, we additionally conducted all analyses mentioned below applying an alternative cut-off of 23 points (representing the lowest quartile of our distribution).

Descriptive analyses were used to describe the degree of incomplete adherence in this sample. Regarding the health-related variables (socio-demographic and clinical information that were rated to be potentially associated with incomplete medication adherence considering current literature) chi-squared/ Fisher’s exact tests were used to evaluate the relationship between categorical variables (sex, education, employment status, diagnosis of hypertension/ type-2 diabetes/ hyperlipidemia/ obesity/ malignant tumor) and incomplete adherence. We used t-tests to assess differences between adherent and incompletely adherent patients regarding metric variables (age, medication information, medication complexity, HRQoL). To examine multivariate associations of socio-demographic and clinical information with incomplete adherence we conducted a multiple logistic regression analysis.

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Figure 1. 1a) degree of adherence 1b) degree of medication information 1c) degree of medication complexity 2a) association of medication information and medication adherence 2b) association of medication complexity and medication adherence 2c) association of age, sex, education,

employment status, quality of life, disease and medication adherence

Results:

A total of 190 patients met the inclusion criteria and took part in the study, providing an analysis sample of 142 male and 48 female participants. In total, 62.1% (n = 118) of the patients were categorized as incompletely adherent. None of the variables were found to be statistically significantly associated (at p < 0.05) with incomplete medication adherence in either univariate or multivariate analyses. This extends to the sensitivity analyses, using an alternative cut-off value of a MARS-D score of 23 points.

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Discussion:

The results of this study indicate that the rates of incomplete medication adherence of German primary care patients with chronic disease are rather high (62.1%; measured via self-report). The cross-sectional design of this study only allowed testing for possible associations between the socio-demographic or clinical variables and incomplete medication adherence, a causal relationship was not to be detected. The finding that incomplete medication adherence is not associated with the patients’ socio-demographic or clinical data conflicts with the results of preceding studies, the vast majority of them being from other countries. Possible reasons accounting for these conflicting results include the applied measurement of adherence, a possible publication bias in the field of medication adherence and a low generalizability of this sample.

To measure the patients’ medication adherence, the MARS-D questionnaire was utilized. In the absence of a gold standard for the measurement of medication adherence, using different measurement tools can lead to variant results when testing for medication adherence.27 Even though direct measurements of medication ingestion (determining blood levels of pharmacological agents) or medication event monitoring systems (MEMS = Medication container with a special closure that records the time and date of each time the container is opened and closed) are said to be more precise, questionnaires about the patient’s adherence (self-reports) are usually used when investigating adherence because they are cheaper, non-invasive, and easier to conduct. However, the adherence rates assessed through questionnaires depend on the patient’s honesty and social desirability bias. While generally providing moderate-to-high concordance with

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higher than pill counts).13,20,27,28 Nevertheless, the MARS-D is considered an appropriate tool to measure medication adherence.20 Although there is no determined cut-off value and therefore no guideline about how to interpret the results, by conducting sensitivity analyses the possibility that different cut-off values lead to different results was excluded. Additional investigations are needed to examine to which extent associations between adherence rates and patient characteristics depend on the type of measurement. The goal should be to find a gold-standard measurement tool that is easy to conduct in a primary care setting and detects incomplete medication adherence accurately.

A further explanation for the inconsistent results could be an underestimated publication bias in the field of adherence. Publication bias is a common problem in other fields of research.29 A previous investigation on the associations of incomplete medication adherence by Vermeire et al.18 reported inconsistent findings with generally small effect sizes. The extent of a possible publication bias should be explored through future meta-analyses. However, meta-analyses that used fail-safe n have estimated the possible risk of unpublished non-significant results in the field of medication adherence to be rather low.22,30

Another possible reason for the disparity of the results is a low generalizability. A limiting factor to the generalizability of this study’s results is the convenience sample that was examined. Including 142 male and 48 female participants, the majority of this sample was male but since gender was not found to be associated with adherence,11 the generalizability should not be reduced by the gender distribution. Differences regarding the patients’ diseases in previous studies and this study could have influenced the results and therefore limited this study, as,

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represents the same problem in research and practice. At least, the participants were recruited consecutively without selection, making up a heterogeneous and fairly representative sample of chronically ill patients treated with medication for chronic diseases like hypertension.26 The high clinical heterogeneity of the analyzed sample provides a meaningful, albeit negative, result on the possible associations of adherence and medication. Based on the sufficient power of the analyses, this negative finding contributes substantially to existing knowledge by showing that we are likely to know less than we sometimes suppose.

The inconsistent results of previous studies investigating incomplete adherence and its associations suggest that incomplete adherence is not just a simple variable that is influenced by a few parameters. Adherence should maybe not be understood as a patient’s characteristic, but rather as a complex and interactive construct that depends on several factors e.g. a patient’s personality and the relationship between the patient and his/her health care provider.31 If the latter was to be confirmed in future studies, strategies to reduce incomplete medication adherence could include interventions focusing on the individual patient as well as interventions focusing on the patient-doctor relationship.

A very important precondition for better adherence is the patient’s will to adhere to the prescribed medication. However, it has been shown that it is not sufficient simply to want something in order to achieve it.32 A person needs an efficient strategy to overcome the intention-behavior gap. A possible strategy to raise adherence rates is the administration of multi-focused interventions including cognitive, behavioral and affective components. Multi-focused interventions are more likely to raise rates of patients’ medical adherence than single-focus

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studies applying such strategies are needed to confirm a positive effect on medication adherence.

Another crucial aspect that seems to influence a patient’s adherence is the patient-doctor relationship12 as poor communication between patients and their physicians can be associated with higher rates of incomplete adherence.36 If the patient-doctor relationship is poor, the patient may not feel free to address his/her concerns regarding the prescribed medication. However, the patients’ individual perceptions are crucial in their decision-making37 and incomplete adherence, even though it may appear irrational to doctors and researchers, can represent a gain in quality of life for patients, for example by reducing side effects. Side effects are the highest concern patients have regarding their information about their medication.31,38 Therefore, specific training for doctors, teaching them how to address patients’ risks and reasons not to adhere to their medication regimen properly, could improve adherence rates in primary care. Future research should examine the influence of such communication training for doctors on the medication adherence of their patients.

In conclusion, at this point we do not have sufficient knowledge about the reasons that account for incomplete medication adherence. Further investigation is needed to explore those reasons and how they can be addressed sufficiently in order to raise adherence rates and thus to make for more favorable clinical outcomes and savings in health care costs.

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References:

1. Sicard P, Zeller M, Dentan G, et al. RICO survey working group: Beneficial effects of statin therapy on survival in hypertensive patients with acute myocardial infarction: data from the RICO survey. Am J Hypertens 2007, 20(11):1133-9.

2. Roik M, Starczewska MH, Huczek Z, et al. Statin therapy and mortality among patients hospitalized with heart failure and preserved left ventricular function - a preliminary report. Acta Cardiol 2008, 63(6):683-92.

3. Halpern MT, Khan ZM, Schmier JK, et al. Recommendations for evaluating compliance and persistence with hypertension therapy using retrospective data.

Hypertension 2006, 47(6):1039-48.

4. DiMatteo MR, Giordani PJ, Lepper HS, et al. Patient adherence and medical treatment outcomes: a meta-analysis. Med Care 2002, 40(9):794-811.

5. Cramer JA, Benedict A, Muszbek N, et al. The significance of compliance and persistence in the treatment of diabetes, hypertension and dyslipidaemia: a review. Int J Clin Pract 2008, 62(1):76-87.

6. Munger MA, Van Tassell BW, LaFleur J: Medication nonadherence: an unrecognized cardiovascular risk factor. MedGenMed 2007, 9(3):58.

7. Stange D, Kriston L, Langebrake C, et al. Development and psychometric evaluation of the German version of the Medication Regimen Complexity Index (MRCI-D). J Eval Clin Pract 2012, 18(3):515-522.

8. McGinnis BD, Olson KL, Delate TM, et al. Statin adherence and mortality in patients enrolled in a secondary prevention program. Am J Manag Care 2009, 15(10):689-95.

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9. Rasmussen JN, Chong A, Alter DA: Relationship between adherence to evidence-based pharmacotherapy and long-term mortality after acute myocardial infarction. JAMA 2007, 297(2):177-86.

10. Ho PM, Magid DJ, Masoudi FA, et al. Adherence to cardioprotective medications and mortality among patients with diabetes and ischemic heart disease. BMC

Cardiovasc Disord 2006, 6:48.

11. DiMatteo MR: Variations in patients' adherence to medical recommendations: a quantitative review of 50 years of research. Med Care 2004, 42(3):200-9.

12. Sabate E: Adherence to long-term therapies: Evidence for action; 2003. Available from:

http://www.who.int/chp/knowledge/publications/adherence_report/en. Accessed: February 9, 2013.

13. Dunbar-Jacob J, Mortimer-Stephens MK: Treatment adherence in chronic disease. J Clin Epidemiol 2001, 54(12):57-60

14. Haynes RB, McDonald HP, Garg AX: Helping patients follow prescribed treatment: clinical applications. JAMA 2002, 288(22):2880-3.

15. Van Eijken M, Tsang S, Wensing M, et al. Interventions to improve medication compliance in older patients living in the community: A systematic review of the literature. Drugs Aging 2003, 20(3):229-240.

16. Chapman RH, Benner JS, Petrilla AA, et al. Predictors of adherence with antihypertensive and lipid-lowering therapy. Arch Intern Med 2005, 165(10):1147-52.

17. Dew MA, Dabbs AD, Myaskovsky L, et al. Meta-analysis of medical regimen adherence outcomes in pediatric solid organ transplantation. Transplantation

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18. Vermeire E, Hearnshaw H, Van Royen P, et al. Patient adherence to treatment: three decades of research. A comprehensive review. J Clin Pharm Ther 2001, 26(5):331-342.

19. Wilke T, Müller S, Morisky DE: Toward identifying the causes and combinations of causes increasing the risks of nonadherence to medical regimens: combined results of two German self-report surveys. Value Health 2011, 14(8):1092-100. 20. Mahler C, Hermann K, Horne R, et al. Assessing reported adherence to

pharmacological treatment recommendations. Translation and evaluation of the Medication Adherence Report Scale (MARS) in Germany. J Eval Clin Pract 2010, 16(3):574-579.

21. Gadkari AS, McHorney CA: Unintentional non-adherence to chronic prescription medications: How unintentional is it really? BMC Health Serv Res 2012, 12(1):98.

22. Grenard JL, Munjas BA, Adams JL, et al. Depression and medication adherence in the treatment of chronic diseases in the United States: a meta-analysis. J Gen

Intern Med 2011, 26(10):1175-82.

23. Schroeder K, Fahey T, Ebrahim S: How Can We Improve Adherence to Blood Pressure-Lowering Medication in ambulatory Care? Systematic Review of Randomized Controlled Trials. Arch Intern Med 2004; 164(7):722-732.

24. Mahler C, Jank S, Hermann K, et al. Psychometric properties of a German version of the "satisfaction with information about medicines scale" (SIMS-D).

Value Health 2009, 12(8):1176-1179.

25. Gellaitry G, Cooper V, Davis C, et al. Patients' perception of information about HAART: Impact on treatment decisions. AIDS Care 2005, 17(3):367-376.

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26. Stange D, Kriston L, von Wolff A, et al. Medication complexity, prescription behaviour and patient adherence at the interface between ambulatory and stationary medical care. Eur J Clin Pharmacol 2013, 69(3):573-80.

27. Horne R, Weinman J, Barber N, et al. Concordance, Adherence and Compliance in Medicine Taking. London: National Co-ordinating Centre for NHS Service Delivery and Organisation R and D; 2005. Available from:

http://www.netscc.ac.uk/hsdr/files/project/SDO_FR_08-1412-076_V01.pdf. Accessed: February 9, 2013.

28. Garber MC, Nau DP, Erickson SR, et al. The concordance of self-report with other measures of medication adherence: a summary of the literature. Med Care 2004, 42(7):649-52.

29. Robertson CT: The money blind: how to stop industry bias in biomedical science, without violating the First Amendment. Am J Law Med 2011, 37(23):358-87.

30. DiMatteo MR: Social support and patient adherence to medical treatment: a meta-analysis. Health Psychol 2004, 23(2):207-18.

31. Steiner JF: Rethinking Adherence. Ann Intern Med 2012, 157:580-585.

32. Gollwitzer PM: Goal achievement: The role of intentions. Eur Rev Sol Psychol 1993, 4(1):141-185.

33. Roter DL, Hall JA, Merisca R: Effectiveness of Interventtions to Improve Patient Compliance: A Meta-Analysis. Med Care 1998; 36(8):1138-61.

34. Gollwitzer PM: Implementation intentions: Strong effects of simple plans. Am

Psychol 1999, 54(7):493-503.

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36. Zolnierek KB, Dimatteo MR: Physician communication and patient adherence to treatment: a meta-analysis. Med Care 2009, 47(8):826-34.

37. Donovan JL, Blake DR: Patient non-compliance: deviance or reasoned decision-making? Soc Sci Med 1992; 34(5):507-13.

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AUTHOR CONTRIBUTION

Jakob Hüther conceptualized the aim and the design of the study, managed the data, performed the statistical analyses, participated in the primary interpretation of findings and drafted the manuscript.

CO-AUTHOR CONTRIBUTION

Alessa von Wolff participated in the conception and design of the study, performed the statistical analyses, participated in the primary interpretation of findings and revised the manuscript critically for important intellectual content.

Dorit Stange participated in the conception and design of the study, collected the data, participated in the primary interpretation of findings and revised the manuscript critically for important intellectual content.

Levente Kriston participated in the conception and design of the study, participated in the primary interpretation of findings and revised the manuscript critically for important intellectual content.

Michael Baehr participated in the conception and design of the study and revised the manuscript critically for important intellectual content.

Dorothee C Dartsch participated in the conception and design of the study and revised the manuscript critically for important intellectual content.

Martin Härter participated in the conception and design of the study and revised the manuscript critically for important intellectual content.

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ACKNOWLEDGEMENTS

This research project, and therefore this dissertation, would not have been possible without the support of the author’s doctorate supervisor Professor Dr. Dr. Martin Härter who lead and oversaw the process of this dissertation with extraordinary professional knowledge, experience and guidance.

My deepest gratitude is also due to the supervisory committee, Dr. phil. Levente Kriston and Dipl. Psych. Alessa von Wolff without whose contagious excitement, profound knowledge and invaluable advice this dissertation would have never reached completion.

Further, I deeply thank Dorit Stange, Dr. Michael Baehr and Prof. Dr. Dorothee C.

Dartsch for supporting me with great care, always providing important intellectual content.

Special thanks are due to Bettina Schwörer for incredible patience and priceless assistance.

The author would also like to convey great appreciation to the Department of Medical Psychology at the University Medical Center Hamburg-Eppendorf in Hamburg, Germany for providing the financial means.

Finally, the author wishes to express his love and gratitude to his beloved family for their understanding, support and endless love.

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EIDESSTATTLICHE VERSICHERUNG

Ich versichere ausdrücklich, dass ich die Arbeit selbständig und ohne fremde Hilfe verfasst, andere als die von mir angegebenen Quellen und Hilfsmittel nicht benutzt und die aus den benutzten Werken wörtlich oder inhaltlich entnommenen Stellen einzeln nach Ausgabe (Auflage und Jahr des Erscheinens), Band und Seite des benutzten Werkes kenntlich gemacht habe.

Ferner versichere ich, dass ich die Dissertation bisher nicht einem Fachvertreter an einer anderen Hochschule zur Überprüfung vorgelegt oder mich anderweitig um Zulassung zur Promotion beworben habe.

Ich erkläre mich einverstanden, dass meine Dissertation vom Dekanat der Medizinischen Fakultät mit einer gängigen Software zur Erkennung von Plagiaten überprüft werden kann.

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