CAPÍTULO 2. MATERIALES Y MÉTODOS
2.2 Posible influencia de la interpolación sobre la calidad de la segmentación
implications for the provision of information and the management of expectations are significant.
3.5
Discussion
This study has demonstrated that during the deliberation phase of decision-making for knee replacements nine key factors play into the decision-making process: stress of deliberation, expectation of outcome, sources of information, personal situation, mental state, coping strategies, loss of control, trust in doctor, and preferred model of care. This then leads to the decision phase. The decision-making threshold marks the boundary between deliberation and decision. Interestingly, the factors that play into decision- making are consistent across decision-making stages.
The strengths of this study include: its focus on one area of decision-making, namely preference based decision-making in total knee replacement; the inclusion of people at various stages of the decision-making process; the broad based research team, including a member of the public who was involved at all stages; the inclusion of a range of ages, genders, and ethnicities within the study; the comprehensive analysis; and thoughtful efforts to demonstrate the trustworthiness of the study.
Weaknesses of this study include it being run over two sites. Although these sites cover a population with a wide rage of sociodemographic characteristics, the range of ethnicities that were present within the study population was limited. This likely reflects to some degree the population the study was based in, but also reflects utilisation rates of orthopaedic services. Medical coding data was used to identify some patients and this demonstrated the proportions of ethnicities were not reflective of the population as a whole. Utilisation of healthcare has been found in previous studies to alter by race.37,38 To
counteract this, the research team went to extensive lengths to ensure as much diversity as it could, and the study population roughly reflects the population demographics of the patients presenting to secondary care with knee OA. However, it is likely that the ethnic minority participants in the study are systematically different to those that underutilise healthcare. Compounding this is that the use of an “opt in” procedure to recruit
participants inevitably leads to selection bias.
I have compared answers from patients across different methods of data collection (focus groups and interviews). This may result in differences being apparent due to the collection method, for example people in the focus groups not feeling able to speak up, or providing a more ubiquitous point of view.79 Given the diversity of opinion and the personal nature of some of the information disclosed in the focus groups I do not think this was a particular issue. However, some differences may persist. Additionally, different methods were used in conducting the interviews, including being conducted on the telephone, in the patient’s home, or at UHCW. This could have altered the discourse, but we felt this was unlikely and, by making entry into the study more convenient, will have addressed some aspects of selection bias.
Reliability statistics for the coding framework were satisfactory. I am confident higher reliability statistics would have been achieved if not for an oddity in the coding framework that allowed the same reference to be coded in two different places (i.e. “motivation” and “mental state”). Altering this would have improved the apparent reliability of the coding.
A further weakness is the power differential generated by the interviewer being an orthopaedic surgeon in training. This may have resulted in more guarded responses. However, this effect may have been reduced by the presence of a member of the public for most interactions.46
The themes identified in this study are consistent with themes identified in other studies across a range of ethnicities, countries, settings, and decision-making stages.67-69 In
contrast to other investigations, this study is the first to include patients at all stages of the decision-making process, which has allowed the triangulation of our results, and a more reliable account of the deliberation process. This has particular relevance when
considering the threshold to decision-making, as I was able to examine it from both sides of the equation. Additionally, only two other studies have examined decision-making in the U.K., both using a population consisting solely of knee replacement patients.71,72 These studies included only patients on the waiting list (i.e. past the deliberation phase) and are therefore subject to limitations of retrospective studies. This study confirms their findings, but also improves their trustworthiness and transferability by including a wider
population base.
Only three studies have included only knee replacement patients in the deliberation phase.67-69 All these studies took place in the USA. One study only interviewed Black Americans, and therefore has limited transferability.67 Another only focused on the concerns of patients, and not the wider decision-making process.69 The third used focus groups to discuss decision-making with patients who had a diagnosis of OA knee in
may not gain sufficient depth of understanding of issues, combined with the use of a single outpatient institution and a small sample size encourage the authors to warn that “It is not possible to assume that the decision-making factors identified by the patients in this study can be generalized to the population of patients with OA who are considering TKA [Total Knee Arthroplasty] at large.” 68
Previous literature has described a threshold to decision-making in investigations into decision-making in knee and hip replacements76and in hip replacements.77 I have taken this work further, by demonstrating this threshold as the boundary between deliberation and decision-making, and establishing that there is a different level of stress at these different stages. This had particular relevance when considering the inclusion of participants at different stages of the decision-making process within this study. All participants in our study demonstrated a threshold to decision-making. This is the first study that has demonstrated this finding in patients’ at different stages of the decision- making process in knee replacements. Understanding this threshold, and the nine factors that influence it, has implications not only in routine clinical practice to facilitate patient- centred care, but also in the development of interventions aimed at supporting decision- making, or facilitating information giving. When combined with the finding that the deliberation process was stressful (a universal finding in our study across all stages of decision-making), these finding suggest that patients are less likely to move back (from decision-making to deliberation) once the threshold has been reached (and they have moved from deliberation to decision-making). This relationship has been demonstrated in Figure 4.
finding as it is contrary to current political movements within the NHS.46 Given the sample size, I would recommend further validation of this finding in different populations, and investigation into other pathologies and interventions.
One of the over arching findings from his study was the complex interplay between all of the themes. It appears that all the factors identified work together to shape a person’s decision, with different factors having different importance to different people. There was one instance of a patient with one overriding theme, which dominated all others (her personal situation dominating her thoughts on a knee replacement due to caring commitments). However, this patient finally decided to have a knee replacement, again using a complex interplay of factors.
3.6
Conclusion
The themes identified here interacted comprehensively with one and other, the result being a complex interplay of factors that affect the deliberation process, the threshold to decision-making, and the ultimate decision. An awareness of the deliberation phase, the factors that influence it, the stress associated with it, preferred models of care, and the influence of the decision-making threshold will aid useful communication between doctors and patients.
Future work, examining how this information might be best translated and utilised in the clinical environment is an exciting avenue. This is one of the key elements in addressing
the three crucial areas set out in the introduction; differences in utilisation rates,31 a high dissatisfaction rate,25 and increasing demands with financial constraints.27 One aspect of this is understanding how outcome prediction would affect the decision-making process for patients, what information they would like, and when in the pathway it would be of most use. The next chapter deals with these questions.