Incidencias especiales y su relación con el pago de ganancias

The symptoms of PD can be extremely debilitating in all aspects of life. What is considered a small complaint by one individual may be significantly troublesome and impactful to another. However, as stated earlier in this thesis, many of the symptoms of PD are treatable to varying extents. Healthcare professionals therefore have the ability to improve the QoL of many people with PD for several years. Unlike decades previous, today’s arsenal of pharmacological agents is more substantial with clinicians having many treatment options available that can be tailored to the patient’s specific needs.

Despite this, however, it is clear from the evidence that some people with PD are not taking their prescribed anti-parkinsonian medication in accordance with medical advice. Furthermore, it is evident that non-adherence to medication in PD results in many people experiencing a ‘wearing off’ of their treatments therapeutic effect. This has been shown to negatively impact on function and QoL. It is therefore essential for clinicians to be able to identify non-adherent PD patients. With a greater knowledge of who is likely to non-adhere to prescribed medication, targeted interventions can be provided in attempt to improve adherence and thus maximise the therapeutic effect of prescribed treatment.

In the next section of this thesis I present the rationale, methods, results and discussion of two systematic reviews. In Chapter 3 I provide the findings of a systematic review identifying what factors are associated with medication non- adherence specifically in PD. In Chapter 4 I present the findings of a Cochrane

33 systematic review on interventions used to enhance medication adherence in people with PD.

34

CHAPTER 3

Factors Affecting Medication Non-

adherence in Parkinson’s Disease

Background Study Design

Risk of Bias/Internal Validity Findings

Discussion

3.1 Background

As highlighted in Chapter 2, to achieve optimum symptom control in chronic conditions medication adherence is imperative. Despite this, the World Health Organization (2003) report that as much as half of all medications prescribed for long-term conditions are not taken as intended. Therefore, it is not surprising that medication adherence is poor in PD.

Leopold et al (2004) reported as few as 10% of a PD cohort showed full adherence. Kulkarni et al (2008) found the prevalence of poor adherence ranged between 60% and 70% when followed over 5-years while Grosset et al (2005a) reported complete medication adherence in as few as 3% of PD patients. These findings are concerning when placed in a clinical context. Kulkarni and colleagues (2008)

35 showed that poor medication adherence increased the risk of worsening symptoms compared to medication adherent people with PD. As PD treatments are self- administered, there is a need for greater understanding of why people do not take their prescribed medications as intended. This theoretical knowledge could help to better understand how best to improve medication adherence in people with PD.

Pharmacological based interventions such as simplifying drug regimens and non- pharmacological approaches such as provision of educational material have been advocated to address non-adherence in PD (Bainbridge and Ruscin, 2009, Grosset and Grosset, 2007). However, whilst these interventions may be beneficial in other chronic conditions, such approaches in a PD population are theoretical because the current evidence on why medication non-adherence develops specifically in PD is limited.

Regardless of the various theories, it remains unclear which factors are associated with non-adherence specifically in PD. The identification of such factors may allow healthcare professionals to identify potentially non-adherent individuals. With this knowledge, the development of targeted interventions to counteract or prevent non-adherence may be possible and could prove beneficial. This is both in terms of symptom management and the clinicians’ understanding of a patient’s treatment response and disease progression.

In the next part of this chapter I outline the processes used to identify which factors are associated with medication non-adherence in people with PD.

36

3.2 Study Design

I used the systematic review approach to identify literature relating to medication non-adherence in PD.

3.2.1 Search Methods

To ensure that both quantitative and qualitative evidence was identified, I performed a systematic search of online databases in April 2011. The five databases searched were Medline (Ovid, 1948), EMBASE (Ovid, 1980), AMED (Ovid, 1985), PsycINFO (Ovid, 1806) and CINAHL (EbscoH, 1982). In January 2012 I updated the search to capture more recently published articles. I also conducted a supplementary hand search of bibliographies of extracted articles and reviews to acquire records not identified electronically. Next I outline the search strategy for the systematic review.

3.2.2 Search Terms

Before conducting the systematic search I reviewed the key words and search strings used by the authors of related articles with the aim of developing a comprehensive set of search terms. When relevant key words were identified I added these to the search string. This practice continued until I was satisfied that I had the key words required to conduct a comprehensive search of the topic. The terms ‘Parkinson’s disease’ and ‘Parkinsonism’ were combined with keywords relating to non-adherence: ‘non-adherence’, ‘non-compliance’, ‘influencing

37 factors’, ‘caregiver compliance’, ‘sub-optimal’, ‘determinants’, ‘drug adherence’, ‘therapy adherence’, ‘drug compliance’, ‘denial psychology’ and ‘therapy compliance’. To make the search strategy more comprehensive, I mapped key terms to database specific subject headings (MeSH). I then ‘exploded’ each MeSH term to include all relevant sub-categories. Truncations and Boolean operators (e.g. ‘and’, ‘or’) were used where necessary to broaden the search window. Exact search strings can be seen in Appendix 1.

3.2.3 Selection Criteria

Once identified records had been imported into the Endnote reference manager and duplicated items had been removed, I proceeded by reviewing all relevant titles and abstracts for potential study inclusion. Full text articles were obtained either where abstracts appeared relevant or when insufficient information was provided from which an adequate assessment of relevance could be made from the abstract alone. Studies meeting the following criteria were included:

(1) English language

(2) Full-article publication available (accessed directly or requested from the study authors)

(3) Idiopathic PD population (iPD) (defined by the authors). (4) All age ranges and duration of anti-parkinsonian treatments.

(5) Presented either quantitative or qualitative data on factors associated with medication non-adherence.

38 3.2.4 Data Extraction

Having identified potentially eligible records, the full text of each article was reviewed for potential inclusion in the systematic review. I developed a concise, standardised data extraction table (Table 3.1) to acquire information relevant to the review from each included study. Extracted data were checked twice for accuracy. Relevant study information was tabulated focusing on study design, methodological characteristics, included participants and the analytical methods used. Extracted data for each included study can be seen in Appendix 2.

Table 3. 1 - Data Extraction Table

Study Design

What was the study design?

What were the aims and objectives?

Participants

What was the sample size?

Were participant demographics reported and how were they collected? How were participants recruited and from where?

Was there specific inclusion/exclusion criteria? Measurement Tools/Outcomes

What was the primary outcome?

Was adherence to medication assessed? If so, what method or instruments were used?

How was the instrument administered and by whom? Statistical Analysis

What analysis was used to determine factors that influence/are associated with medication adherence?

Were covariates identified and included in the analysis?

Results

What were the response rates?

39 In the next section of this Chapter I will describe the procedure used to assess the risk of bias of the studies included in this systematic review.