UNIVERSITY OF CALGARY. Selection of Peritoneal Dialysis Among Older Eligible Patients with End-Stage Renal Disease. Ben Chun-Tung Wong A THESIS

Transcription

1 UNIVERSITY OF CALGARY Selection of Peritoneal Dialysis Among Older Eligible Patients with End-Stage Renal Disease by Ben Chun-Tung Wong A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN COMMUNITY HEALTH SCIENCES CALGARY, ALBERTA APRIL, 2016 Ben Chun-Tung Wong 2016

2 Abstract This study seeks to explore potential patient and care provider barriers that may explain why older patients with end-stage renal disease (ESRD) are less likely to choose peritoneal dialysis (PD). A mixed methods approach was used: survival analysis was performed on administrative data of patients deemed eligible for both PD and hemodialysis (HD); semistructured interviews were also conducted with older patients. We found PD and HD are associated with similar survival in incident dialysis patients regardless of patient s age, and the effect of modality on survival did not vary with follow-up time. Selection of a particular dialysis modality is highly personal and is driven by patient preference for the convenience and maintenance of a normal life provided by PD versus the heightened sense of security afforded by in-centre HD. Addressing these issues when counselling about dialysis choice may help increase PD uptake among older ESRD patients. ii

3 Acknowledgements I would like to thank my supervisor, Dr. Jayna Holroyd-Leduc and my co-supervisor, Dr. Rob Quinn, for their continuous support and guidance amidst their busy schedules. I would also like to thank the other members of my thesis committee, Drs. Pietro Ravani and Lorraine Venturato, for their time and expertise in the respective areas of statistics and qualitative research. I would like to acknowledge the support of Dr. Matthew Oliver and other staff associated with the home dialysis programme at Sunnybrook Health Sciences Centre, and the support of Dr. Amit Garg. Also, the countless hours that Ms. Monika Khoury-Dool spent transcribing the interviews is very much appreciated. Finally, I would like to thank all the study participants for their time and willingness to share their unique perspectives. This study was supported by the Institute for Clinical Evaluative Sciences (ICES) Western site. ICES is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). Core funding for ICES Western is provided by the Academic Medical Organization of Southwestern Ontario (AMOSO), the Schulich School of Medicine and Dentistry (SSMD), Western University, and the Lawson Health Research Institute (LHRI). The research was conducted by members of the ICES Kidney, Dialysis and Transplantation team, at the ICES Western facility, who are supported by a grant from the Canadian Institutes of Health Research (CIHR). The opinions, results and conclusions are those of the iii

4 authors and are independent from the funding sources. No endorsement by ICES, AMOSO, SSMD, LHRI, CIHR or the MOHLTC is intended or should be inferred. Parts of this material are based on data and information compiled and provided by Canadian Institute for Health Information (CIHI). However, the analyses, conclusions, opinions and statements expressed herein are those of the author, and not necessarily those of CIHI. iv

5 Table of Contents Abstract.. ii Acknowledgements... iii Table of Contents.. v List of Tables..vii List of Figures..... viii List of Abbreviations.... ix Chapter One: Introduction Background Significance of end-stage renal disease Potential advantages of peritoneal dialysis Under-utilization of PD Study Purpose Contraindications and barriers to PD Potential patient biases Potential care provider biases Study objective Research questions Chapter Two: Methods Quantitative component.. 9 v

6 2.1.1 Data source Patient population Statistical analyses Qualitative component Participants Research approach Chapter Three: Results Quantitative component Qualitative component Choice of dialysis modality Summary of themes Chapter Four: Discussion Findings from quantitative component Findings from qualitative component Overall summary. 47 References Appendix: Interview protocol vi

7 List of Tables Table 1 Baseline characteristics of all included patients.. 18 Table 2 Baseline patient characteristics as per cohort definition Table 3 Quotations from participants to illustrate each theme, mapping to the COM-B system vii

8 List of Figures Figure 1 Survival curves of patients eligible for both modalities Figure 2 Survival curves of patients eligible for both modalities with outpatient dialysis starts Figure 3 Key factors in dialysis modality selection mapped to the COM-B items of Capability, Opportunity, and Motivation viii

9 List of Abbreviations Symbol Definition ESRD PD HD RCT ICES DMAR CORR RPDB COM-B TDF AVFs end-stage renal disease peritoneal dialysis hemodialysis randomized-controlled trial Institute for Clinical Evaluative Sciences Dialysis Measurement Analysis and Reporting Canadian Organ Replacement Register Registered Persons Database Capability, Opportunity, Motivation Behaviour Theoretical Domain Framework arteriovenous fistulas ix

10 Chapter One: Introduction 1.1 Background Significance of end-stage renal disease With an aging population, those 75 years and older represent the fastest growing segment of the dialysis population (1). The majority of older end-stage renal disease (ESRD) patients are either not suitable for a kidney transplant, or must wait a number of years on dialysis for a transplant. Compared to their peers in the general population, older ESRD patients have substantially higher rates of morbidity and mortality. Among dialysis patients age 65 and older, mortality is seven times greater than for individuals in the general population and is twice as high as for patients in the general population who have other significant comorbidities, such as diabetes, cancer, or congestive hearth failure (2). Cardiovascular disease is common among ESRD patients and accounts for ~50% of deaths. Management of ESRD, especially among older patients, presents a significant resource strain to our health care system. The cost of caring for patients with ESRD is considerable, largely driven by the provision of chronic dialysis (3). In 2005, Canada spent over $1.8 billion (1.2% of all health care spending) caring for patients with ESRD, despite the fact that they make up less than 0.1% of the population (3). 1

11 1.1.2 Potential advantages of peritoneal dialysis Peritoneal dialysis (PD), which first originated in the 1980 s, is a continuous form of dialysis that allows ESRD patients to dialyze at home. It is an effective form of renal replacement therapy and may have advantages compared to hemodialysis (HD), including less stringent dietary potassium restriction and potential preservation of residual renal function (4,5). PD affords independence as patients are able to self-administer dialysis at home and compared to HD, it is a less intrusive form of therapy among older dialysis patients (6). For fit older patients, PD enables travel, an active social life, and the opportunity for employment. Among frail older patients, PD can avoid the poorly tolerated hemodynamic instability associated with HD and the need for transportation to and from dialysis (7). In addition, economic evaluations have demonstrated that PD affords cost savings to the healthcare system compared to conventional in-centre HD, largely due to the fact that less intensive nursing care is required (8,9) Under-utilization of PD Despite these attractive features, PD remains an under-utilized therapy. In countries that adopt a PD-first policy, such as Hong Kong, PD accounts for over 80% of renal replacement therapy. However, in jurisdictions where patient choice is an important element of decision making, HD remains the most common modality. The reasons for this variability are complex and multi-factorial, ranging from government policy to physician prescribing patterns, a lack of familiarity with the therapy in certain jurisdictions, and different physician reimbursement structures (1,10). While strategies to increase PD have been 2

12 implemented in many jurisdictions, the majority of ESRD patients in Canada (~80%) receive conventional thrice-weekly intermittent HD in a satellite or in-center dialysis unit (11). Older patients in particular, are more likely to start HD therapy. Although older age has been found to be associated with more contraindications to PD, older patients also tend to prefer HD for reasons that are not clear (12,13). A potential knowledge-to-action gap (14) exists and further research is needed in an attempt to increase appropriate uptake of PD among older patients with ESRD. 1.2 Study purpose The purpose of this study is i) to explore modifiable barriers to PD selection among older patients with ESRD, and ii) to determine if there is a mortality difference for incident patients starting on PD compared to those starting on HD. This thesis will examine the potential biases and misconceptions from the perspective of the patient; exploring potential reasons why older ESRD patients choose PD less often than would be expected based on eligibility. It will also explore if difference in adjusted mortality rates should be a consideration when selecting dialysis modality Contraindications and barriers to PD First, it is important to make the distinction between contraindications and barriers to PD (15). Absolute contraindications to PD can be defined as physical and social conditions that, independent of support, preclude patients from being eligible for PD. Examples include 3

13 patients with previous abdominal surgeries and subsequent peritoneal scarring or those residing in long-term care facilities that do not permit PD. Barriers, on the other hand, represent physical or cognitive conditions that would interfere with patients being able to safely perform self-care PD, but could potentially be overcome with assistance. A typical example would be an older ESRD patient who does not have adequate social support at home. Barriers are often confused as contraindications and may be a reason why PD uptake is less common among older patients. Indeed, the provision of assisted PD (using community-based home care), which has been implemented in countries such as France and Canada, addresses potential social barriers and has led to increased PD uptake (16,17) Potential patient biases Older patients may have a pre-conceived notion that self-care dialysis is inferior to incentre dialysis provided by a health care professional. Increasing age has been found to be associated with fear that home-based treatments were substandard compared to in-centre dialysis in a sample of HD patients (18). Furthermore, patients may not be informed about the various dialysis modalities. A study from the United States noted that an incomplete presentation of treatment options is an important reason for underutilization of home dialysis therapies (both PD and home HD); 66% of ESRD patients were not presented with PD as a treatment option (19). This study also highlighted that the selection of PD is related to whether PD is presented as a treatment option and the amount of time spent on related patient education (19). 4

14 Several qualitative studies have been conducted to explore the influences and specific factors that patients identify as significant in choosing a specific dialysis modality (20-31). However, most of these studies did not specifically focus on patients who have been systematically determined to be eligible for both dialysis modalities, provided uniform modality education, and allowed to choose either PD or HD. Inherently, patients perceptions identified through these studies may be clouded by their lack of choice, their underlying contraindicating physical and social factors, and variations in modality education. Moreover, previous studies included mostly younger patients whose perceptions about dialysis modalities may differ from those of older patients. Finally, most studies included prevalent HD and PD patients. Patients perceptions may change over time and they may not necessarily recall their initial reasons for choosing a particular dialysis modality. It would be important to identify patient-perceived factors that influence their choice of dialysis modality at or close to the time that they make decisions Potential care provider biases Clinicians may be less likely to offer PD as a potential dialysis option to older patients, deeming them to be too frail to safely administer PD independently at home. This is particularly important since there is evidence that healthcare teams will respond by making dialysis treatment decisions on behalf of older patients (7). Therefore, there is a real risk among older patients that the modality favored by the renal team becomes the treatment of choice (7). 5

15 Some clinicians may not offer PD to older ESRD patients with the pre-conceived notion that mortality is higher with PD. However, there remains equipoise regarding potential differences in mortality outcomes between PD and HD. Numerous studies have been conducted in this area with mixed results (32-38). The one and only randomizedcontrolled trial (RCT) on this subject failed due to difficulty with patient recruitment (34). Patients often develop strong preferences for a particular dialysis modality during the informed consent process and are unwilling to undergo randomization. Another RCT to address this question is not likely to occur. As a result, most studies in this area are cohort studies, many using registry data and all with inherent problems with selection bias and threats to internal validity. The biggest threat is the fact that sicker, frailer patients are often ineligible for PD. Traditional analyses included a substantial proportion of these patients (~ 25-30%), thus biasing any mortality difference that might be observed between the dialysis modalities. These analyses do no necessarily inform clinical decision-making because patients faced with a choice in dialysis modality are the ones who are eligible for both modalities. Furthermore, patients who require urgent dialysis initiation in hospital are almost always treated with HD and these patients naturally have a poorer prognosis. While numerous statistical techniques have been used to adjust for differences between the PD and HD populations, residual confounding threatens the validity of the results Study objective The objective of this study is to identify modifiable barriers to PD selection among older patients with ESRD. Ultimately, these modifiable barriers need to be considered within the 6

16 context of a knowledge-to-action framework (14), which provides an approach to putting knowledge into action. According to this framework, identifying modifiable barriers to PD uptake is required in order to inform development of an appropriate intervention, implementing it, and subsequently evaluating outcomes in an iterative manner, with the end goal of maximizing the safe, appropriate, and effective use of PD among older ESRD patients. In order to identify potential reasons why older ESRD patients preferentially start renal replacement therapy on HD, we must first exclude patients who are confirmed ineligible for PD (defined as presence of contraindications to PD). By focusing on a specific cohort of patients who have been determined to be eligible for both dialysis modalities, a meaningful analysis can be performed to identify potential PD barriers that are not confounded by patients underlying contraindicating physical and social factors. Subsequently, this cohort would also afford a better comparison of mortality rates between those who select PD vs. those who select HD. 1.3 Research questions By focusing on a specific cohort of patients who have been determined to be eligible for both PD and HD by a multi-disciplinary team (consisting of nephrologists, nurses, and social workers) in an objective manner, the proposed study provides an opportunity to help clarify potential patient- and care provider-level barriers. The research questions are, 7

17 among older ESRD patients who are deemed eligible (defined as absence of any contraindications) for both PD and HD: What are the patient-perceived factors and barriers that influence older ESRD patients choice of dialysis modality? Is there a mortality difference for incident patients starting on PD, compared to HD, after adjustment for important covariates and stratifying by age? 8

18 Chapter Two: Methods A mixed methods approach using both quantitative and qualitative components was used for this study. The study was approved by the Conjoint Health Research Ethics Board at the University of Calgary and the Research Ethics Board of Sunnybrook Health Sciences Centre in Toronto, Canada. 2.1 Quantitative component We conducted a retrospective cohort study using de-identified administrative health data stored at the Institute for Clinical Evaluative Sciences (ICES) in Toronto, Canada Data source The Dialysis Measurement Analysis and Reporting (DMAR) database prospectively captures outcomes related to incident ESRD patients after they have decided on a renal replacement modality. The data is double-reviewed by experts in real-time and includes patients from multiple Canadian regional/provincial dialysis programmes. It captures baseline demographic data and comorbidities, in addition to primary renal diagnosis and dialysis modality of individual patients at the time of dialysis initiation. Dates of death, dialysis modality switches, renal transplantation or withdrawal from dialysis are updated every 90 days by the respective dialysis centers. Using encrypted versions of patients 9

19 unique health insurance numbers, the following datasets were linked to DMAR: Canadian Organ Replacement Register (CORR) and Registered Persons Database (RPDB). Data from January 2004 to December 2013 was used to address the research questions Patient population As part of DMAR, consecutive incident patients 18 years or older starting dialysis at each participating centre were included if they: (i) had a diagnosis of ESRD confirmed by a nephrologist and had received at least one dialysis treatment and (ii) were deemed both PD and HD eligible after completing a multidisciplinary modality assessment. A multidisciplinary team including a nephrologist, pre-dialysis nurse(s), PD and/or acute care nurse(s), +/- social worker met every 2 weeks at the respective regional dialysis programmes to review incident dialysis patients to ensure that they were all assessed to determine eligibility for HD and PD using a structured assessment, educated about their treatment options, offered the therapies they were candidates for, and allowed to make an informed choice. Barriers and contraindications to PD, as well as the availability of support in the home were documented. Patients with complex medical conditions or social situations were often discussed at multiple meetings until a final decision regarding PD eligibility could be made. Patients who had previously received a renal transplant and those who had recovered renal function within 180 days of dialysis initiation were excluded. 10

20 Three different cohorts of patients were constructed for analyses: all patients regardless of their PD eligibility (cohort 1), patients eligible for both dialysis modalities (cohort 2), and patients eligible for both modalities who started dialysis electively, as outpatients (cohort 3) Statistical analyses The exposure of interest corresponded to the initial dialysis modality; the primary outcome was all-cause mortality. Follow-up began on the date of first outpatient dialysis session. For patients who started dialysis as outpatients, this was the same as the start date of dialysis ; for patients who started dialysis in hospital, this was the date of discharge from hospital, even if the first outpatient treatment occurred several days after leaving hospital. We used an intention-to-treat approach, based on the dialysis modality chosen at baseline, defined as the dialysis modality used for the first outpatient treatment. Patients were followed for the outcome of all-cause mortality until one of transplantation, loss to followup, recovery of renal function after 180 days, or the end of study period. Changes in dialysis modality were not censored. We included covariates that have previously been shown to potentially modify the relationship between dialysis modality and all-cause mortality. These included demographic variables (age, sex, self-reported race), socioeconomic status as defined by neighbourhood income quintile, primary renal disease (diabetes, hypertension, glomerulonephritis, polycystic kidney disease, other), inpatient dialysis start, comorbid 11

21 medical conditions (presence of diabetes, coronary artery disease, congestive heart failure, cerebrovascular disease, malignancy, peripheral vascular disease), the receipt of a minimum of 4 months of pre-dialysis care, and baseline laboratory variables (hemoglobin, creatinine, and albumin). All analyses were conducted using Stata, version 13.1 (Stata Corp). Categorical variables were tabulated as frequencies; continuous variables were presented as means with corresponding standard deviations. Baseline characteristics were compared between those who selected PD versus those who selected HD using Chi-square tests (or Fisher's exact test where appropriate) for categorical variables and independent sample Student T- tests for continuous variables. Missing categorical values were replaced with the most frequently occurring category for each respective variable; missing income quintile values were replaced by the median. Missing continuous variables were replaced by the mean value for the corresponding modality. The covariates were screened for collinearity. Survival analyses were performed on the three cohorts using a full Cox proportional hazards model, which factored in dialysis modality, all covariates, and several interaction terms (age x modality, sex x modality, and diabetes x modality) previously shown to impact the relationship between dialysis modality and survival (32, 33, 35, 36, 37, 38). Interaction terms were only retained if they were significant at a p-value of <=0.05. Afterwards, the proportional hazards assumption was tested using Schoenfeld residuals and graphically, using log-log plots. 12

22 2.2 Qualitative component Participants A convenience sample of participants were chosen from Sunnybrook Health Sciences Centre in Toronto, Canada to include a roughly proportionate mix of pre-dialysis/dialysis patients deemed eligible for both dialysis modalities, and who had chosen HD or PD, or who were as yet undecided. Sunnybrook Health Sciences Centre participates in DMAR. Sixteen semi-structured face-to-face interviews were conducted with eligible patients. All patients had completed a multidisciplinary modality assessment, were deemed eligible for both PD and HD, and had received modality education. Dialysis modality education was not designed in any way to sell home dialysis and it was reviewed to ensure both dialysis modalities were presented in an unbiased manner. Pre-dialysis patients and those who had initiated dialysis within the preceding six months were included in the study. Additional inclusion criteria included: 1) medical stability with no acute medical problems or hospitalizations within the preceding month, 2) no obvious significant cognitive impairment, 3) English-speaking, 4) 65 years of age or older, and 5) willingness to provide informed consent Research approach 13

23 A semi-structured interview protocol (Appendix) was used to guide the interviews, with questions designed to focus on the following areas: 1) perceived advantages/disadvantages of HD and effect on quality of life, 2) perceived advantages/disadvantages of PD and effect on quality of life, and 3) decision making process used for modality selection and exploration of internal/external factors that influenced the decision. Prior to conducting the interviews, the interview protocol was revised iteratively based on feedback from physicians and nurses with relevant content knowledge. An Independent Dialysis Navigator at Sunnybrook Health Sciences Centre provided the interviewer (BW) with a list of eligible patients. The interviewer, not involved in the care of the patients, approached these patients in person regarding participation in the study, explained the study purpose, and obtained informed written consent from those interested. Pre-dialysis patients who had selected a preferred dialysis modality and current HD and PD patients were interviewed until data saturation was reached (39). All interviews lasted between 30 to 60 minutes, were digitally audio-recorded, and transcribed verbatim with standard linguistic conventions for analysis. Transcripts were entered into NVivo, version 10.2 (QSR International), a computer software used to store, code, and search data. Transcripts were read repeatedly to derive potential codes using line-by-line textual analysis (BW). The Capability, Opportunity, Motivation Behaviour (COM-B) and Theoretical Domain Framework (TDF) were used to help guide the coding framework 14

24 (40,41). The coding framework, along with supporting quotes, was reviewed and verified by two additional researchers (JHL and LV). Potential barriers to implementing practice change (including professional and other health-related behaviours) can be explored using the TDF (41). The TDF framework comprises 14 domains of theoretical constructs ( knowledge, skills, social/professional role and identity, beliefs about capabilities, optimism, beliefs about consequences, reinforcement, intentions, goals, memory, attention and decision processes, environmental context and resources, social influences, emotions, and behavioural regulation ) and had been validated for use in behaviour change and implementation research. As an extension of the TDF, the COM-B system and behaviour change wheel were developed as a method of mapping potential barriers to appropriate behaviour change interventions (40). The COM-B system involves three essential conditions: capability (physical and psychological), opportunity (social and physical), and motivation (automatic and reflective). We believe this framework is appropriate in guiding the development of a coding scheme applicable to the evaluation of dialysis modality selection that is guided by patient choice. Previous studies have identified that patients often perceive a lack of choice in decision making across all treatments for chronic kidney disease (31). All patients in our study were provided both PD and HD modality education and invited to choose a preferred dialysis modality. The assumption is that natural behaviour stems from free choice. 15

25 Chapter Three: Results 3.1 Quantitative component A total of 2146 patients (1693 HD; 453 PD) were included in the study (cohort 1). HD and PD patients differed in many of their baseline characteristics; HD patients were older and had a higher frequency of diabetes, coronary artery disease, congestive heart failure, cerebrovascular disease, malignancy, and peripheral vascular disease (Table 1). They also initiated dialysis with a lower hemoglobin and albumin, had more inpatient dialysis starts, and were less likely to have received at least 4 months of pre-dialysis care. After completion of multidisciplinary modality assessments, a total of 1376 patients (926 HD; 450 PD) were deemed to be eligible for both dialysis modalities (Table 2, cohort 2). Among this cohort, HD patients also had a higher burden of comorbidities and more inpatient dialysis starts. After further restricting to patients with outpatient dialysis starts (Table 2, cohort 3), baseline characteristics between HD and PD patients were more homogenous; case-mix differences in primary renal disease, and prevalence of diabetes and congestive heart failure were no longer statistically significant. A significant interaction term between age and dialysis modality was found, and therefore, the final adjusted model was stratified by age (less than 65, 65 to 74, greater than and equal to 75). Among all included patients (cohort 1), PD was not statistically different than 16

26 HD with respect to all-cause mortality. However, the proportional hazard assumption was violated, and subsequently, the analysis time was split. There was no statistical difference in all-cause mortality between PD and HD for the age groups, 65 to 74, and greater than and equal to 75. However, in the age group, less than 65, HD was associated with a significantly higher risk of death when compared to PD (adjusted HRHD:PD = 1.81; 95% CI 1.08 to 3.04). 17

27 Table 1. Baseline characteristics of all included patients Variable HD PD P-value Total number of patients Mean age (SD) 67.0 (15.3) 64.8 (14.8) Female gender (%) Race (%) Caucasian Asian Black Other Unknown Income quintile 1 (%) Primary renal disease (%) Diabetes Glomerulonephritis Other Polycystic kidney disease Renal vascular Inpatient dialysis start (%) <0.001 Diabetes (%) Coronary artery disease (%) <0.001 Congestive heart failure (%) <0.001 Cerebrovascular disease (%) <0.001 Malignancy (%) <0.001 Peripheral vascular disease (%) <0.001 Received pre-dialysis care >= 4 months (%) <0.001 Mean hemoglobin (g/l) (SD) 96.3 (19.5) (14.4) <0.001 Mean egfr (ml/min/1.73 m 2 ) (SD) 9.4 (9.9) 8.6 (3.3) Mean albumin (g/l) (SD) 33.3 (17.0) 37.7 (5.4) < lowest income quintile = 1, highest income quintile =

28 Table 2. Baseline patient characteristics as per cohort definition Patients eligible for both modalities who Patients eligible for both modalities Variable started dialysis as outpatients HD PD P-value HD PD P-value Total number of patients Mean age (SD) 65.3 (16.0) 64.7 (14.8) (16.2) 64.1 (14.4) 0.9 Female gender (%) Race Caucasian Asian Black Other Unknown Income quintile (%) Primary renal disease (%) Diabetes Glomerulonephritis Other Polycystic kidney disease Renal vascular Inpatient start (%) < Diabetes (%) Coronary artery disease (%) Congestive heart failure (%) < Cerebrovascular disease (%) < Malignancy (%) Peripheral vascular disease (%) Received pre-dialysis care >= < months (%) Mean hemoglobin (g/l) (SD) 96.4 (16.8) (14.4) < (15.6) (13.8) <0.001 Mean egfr (ml/min/1.73 m 2 ) (SD) 8.8 (9.1) 8.5 (3.1) (3.4) 8.4 (3.0) 0.3 Mean albumin (g/l) (SD) 34.6 (22.1) 37.8 (5.4) < (6.0) 38.0 (5.3) < lowest income quintile = 1, highest income quintile =

29 Among all patients eligible for both dialysis modalities (cohort 2), PD was associated with a significantly lower risk of death when compared to HD in the unadjusted analysis (unadjusted HRPD:HD = 0.77; 95% CI 0.61 to 0.97), but the effect disappeared after adjusting for important baseline characteristics (adjusted HRPD:HD = 1.08; 95% CI 0.83 to 1.41). The effect of modality on survival did not vary with follow-up time, thus satisfying the proportional hazard assumption. Adjusted survival curves for the two modality groups, for each of the age strata (< 65, 65 74, >=75), are presented in Figure 1. 1.a. 20

30 1.b. 1.c. Figure 1. There was no significant difference in adjusted survival between patients treated with PD and HD among those deemed eligible for both modalities for each of the three age groups: a) < 65 b) 65 to 74 c) >=

31 When the analysis was repeated for eligible patients who started dialysis electively, as outpatients (cohort 3), HD and PD were again found to have similar risks of all-cause mortality (unadjusted HRPD:HD = 0.84; 95% CI 0.63 to 1.12, adjusted HRPD:HD = 1.21; 95% CI 0.87 to 1.67). Once again, the proportional hazard assumption was satisfied. Adjusted survival curves for the two modality groups, for each of the age strata, are presented in Figure 2. 2.a. 22

32 2.b. 2.c. 23

33 Figure 2. There was no significant difference in adjusted survival between patients treated with PD and HD among those deemed eligible for both modalities who started dialysis electively as outpatients for each of the three age groups: a) < 65 b) 65 to 74 c) >= Qualitative component We interviewed a total of sixteen patients, half of whom were females. While most patients selected a dialysis modality soon after the receipt of modality education (9 PD, 5 HD), two patients remained undecided. Six patients were between the ages of 65 to 70, seven were between the ages of 71 to 79, and three patients were age 80 or older. Seven patients had started dialysis as inpatients, and three of these individuals eventually decided on HD. Many of the patients had immigrated from the Middle East, Caribbean, or Asia. A family member accompanied the patient during one-third of the interviews Choice of dialysis modality Overall, patients did not sense bias in the modality education provided to them: They give us like a manual about all types of dialysis that we can use and read the advantage and disadvantage of each one And we had two sessions. One before we had this manual was [with] a dialysis nurse, and after that too, we came back with tons of questions, after we had a chance to read the manual, so of course it gives you all the advantage and disadvantage of each so we came back with all these questions and we were well informed I should say too before making a final choice. 24

34 Rather, patients perceived autonomy in choosing their preferred dialysis modality: I ve spoken to different people but in the end, I mean obviously I heard what they have to say and I decided to do this way Summary of themes For most patients, their choice of a dialysis modality was the result of a combination of factors, although some patients were able to identify a primary reason for their choice of a particular dialysis modality. Patients choice of dialysis modality were mainly influenced by (Figure 3): i) physical strength and dexterity/sound mind, ii) iii) external forces/constraints, values and beliefs. 25

35 Figure 3. Key factors in dialysis modality selection mapped to the COM-B items of Capability, Opportunity, and Motivation. These key factors can be mapped to the COM-B items of Capability (physical strength and dexterity / sound mind), Opportunity (external forces / constraints), and Motivation (values and beliefs), and analyzed further using the sub-themes in each category (Table 3). Capability - physical strength and dexterity / sound mind Some patients acknowledged the need to have adequate physical capacity, manual dexterity, and a sound mind to self-administer PD at home. This was particularly relevant when patients were uremic and in need of imminent dialysis. Reference with respect to physical strength was made both regarding setting up the PD equipment and the disposal of supplies: Your strength to lift this stuff to put on the machine the bags of stuff, then you have to cut these boxes up, lots of boxes, every day you have about two boxes to throw out so you have to take a knife. Opportunity - external forces / constraints The theme external forces / constraints described all the factors extrinsic to the individual that influenced patients modality selection. 26

36 Employment A few patients continued to work and their choice of dialysis modality reflected the need to maintain regular daytime employment: They said that PD would take place all night so that will give him the chance while he s resting he doesn t feel he need to break his day to come here to the hospital all day because he still works. Home environment The home environment with respect to adequate physical space to accommodate the PD machine, and more importantly, the supplies, was pertinent to PD selection: If we would have met somebody on it (PD), that it would have made a big difference and saw what it meant in the house, and how much time and space you need. On time / transportation For some patient, the requirement to arrive at HD on time posed a potential concern due to the distance between their residence and the HD facility and the possibility of inclement weather, while others had faith in keeping their scheduled HD spot with the pre-arranged special transportation service: I live far from the hospital so, you know, with the winter especially, the snow or something like that, I can t keep a time you know, you have to keep the time exactly for the hospital, so if the weather is bad or something happen and I can t keep the time. Wheeltrans is a transportation system that they set up that they pick you up at your home and bring you here and its $2.00 only. They are very reliable and really good. 27

37 They call you the night before and tell you the time they are going to pick you up and they take me home from the hospital too. Support For some patients who had selected PD, the availability of caregivers to help administer PD in their own homes and the availability of around-the-clock support by telephone provided reassurance for those living alone; for others who had a co-habitant, the other person played a significant role in terms of being a back-up support. I could have the nurse (from home care) for the rest of my life, or if I m independent, I can have them until I tell myself I can do it on my own, and even though I am doing it on my own, there are mistakes to be made and they are only a stone throw away. I m a backup definitely I m always going to be there for (spouse) definitely for support and everything and I will be learning how to do the dialysis with (spouse). I ve already learned a lot with changing the dressing too for the catheter because sometimes it gets overwhelming for (spouse) to do all that on (spouse) own, so I think we are going to carry on with trying to do the PD as well. External influences - patients were also influenced to various extents by their family, friends, and interactions with health care professionals, regardless of their reason(s) for selecting a particular dialysis modality: It s just a fact that the PD, my friend has been on it for so many years, so that might have been encouragement. 28

38 Motivation - values and beliefs The theme values and beliefs referred to patients intrinsic thought processes that consciously and subconsciously modified their modality decision-making. For most patients, their modality selection evolved mostly around sub-themes in this area. Normal life The ability to continue to live a life that resembled their regular life, prior to the need for maintenance dialysis, was important to some patients, especially with consideration of the possibility of dialyzing at night: The most important effect is to keep your life and to see which one is the best for maintaining your normal life or much close to normal situation. Burden Patients expressed concern about the effect of their treatment on their family, both in terms of transporting the patient to a health facility for in-centre HD and helping with self-administering PD at home: I live with my daughter and she has 3 kids, one is married now so it s only the two, and to me, it s hard for the family to have somebody like you who needs help and everything, so I think I like coming over.. Convenience and flexibility The comfort afforded by PD (enabling patients to dialyze in their own homes with the supplies delivered to them) and the ability to select 29

39 their PD regimen (especially being able to dialyze overnight and have their day schedule open) were very important to some patients: To do it at home at night time would be convenient and it would give me free day to do whatever I like to do. In a hospital it wastes my day. I have to come for few hours, and you know, it ruins my day. That s the main thing. Daily dialysis Some patients valued the days off from any HD treatments as opposed to requirement for daily administration of PD; they felt empowered to spend those days however they want: But later on, I thought, the peritoneal is an everyday thing so I thought that for a while, to come to the hospital to come for the hemo you come and then you know for sure you are done that four hours you are done. And also, I have two days on my own without any dialysis I can go anywhere and I know for sure that two days are for me. I like to enjoy that. Time with my family very important. Home separate from hospital Similar to the theme of daily dialysis, some patients preferred to keep their homes separate from the hospital and to avoid medicalizing their homes by choosing HD: To do it at home your home is constantly a hospital. You are constantly never let free of doing the dialysis; whereas when you come to the hospital you have a few days, and when you go home you can enjoy your home. 30

40 Relations Relationship with nurses and other patients was important to some patients. For patients who had selected HD, some of them shared a bond with other patients because they felt they were interacting with people who could relate to their own medical problems. For PD patients, they developed a familiarity with the nursing staff because they interacted with the same staff during their training and there were much fewer PD nurses in comparison to HD nurses. Everybody here has been kind and friendly and told me how long they ve been on dialysis, talk to the people around me, and I am getting to feel concerned for them. socialization at the same time. Whoever s on duty you speak with them but after the month of doing it, you start to feel your missing some of them because you used to go in for training and you get to know them and they speak to you and you start to get a bond. Dependence Some PD patients did not like being dependent on others when they felt they were still capable of caring for themselves; others who chose HD felt reassured that their care was dependent on their family or nursing staff: I felt I was still capable of doing it myself. There was less dependence on other people. And also my blood pressure is checked and monitored and also the main injections that I receive, the iron and then Epo injection are also given through the machine, so you don t need to do that. These things are little mental satisfaction for me. 31

41 Dialysis mechanism / vascular access / blood The type of vascular access in relation to the respective dialysis modality was relevant to some patients. Patients took into account the procedures required for access creation (including the potential need for multiple surgeries for non-functional arteriovenous fistulas (AVFs) and potential exposure to blood with HD: They said that it may not work in there, my blood vessel was too small or whatever it was, they said they may have to go up here might have been a secondary factor but I mean they check it and they said that may not be put it in here, then the other started to talk about the other parts and I decided to go with this (peritoneal dialysis). Security Performing dialysis independently was a barrier for some patients, especially those who lived alone or with an older spouse. These patients remained apprehensive in spite of the knowledge that help was available (by phone) at all times and that assisted PD (whereby a home care nursing staff assists with the connection/disconnection of PD equipment at their homes) could be arranged. Patients also sensed improved safety from supervised dialysis treatment due to their underlying medical co-morbidities and the potential of missed infections when dialyzing alone: Really, fear fear more than anything is fear in case something goes wrong and no one is there to help me because nobody is in the apartment to help me or know about it 32

42 Purpose For some patients, attending HD sessions provided them a reason to leave their house in spite of the time commitment required when coming to dialysis: That means I have a purpose every day. I mean, 3 times a week that I have an appointment to go. Night therapy / sleep The option to perform PD at night during sleep was important to some patients given the resultant freedom afforded them during the day. However, this also posed potential concerns for other patients because of the potential effects on their sleep, especially if they were on other medical therapies at night, such as CPAP for treatment of obstructive sleep apnea. Some patients were also concerned about being connected to the PD machine at night if they had to use the bathroom. The freedom of doing more, getting more done by doing it at home while you are sleeping. That is what attracted me. And if I can do that, get a good sleep, wake up next morning, I have the whole day and part of the night. I am a person who don t sleep well, it has been like that for me even before I had kidney problems, I sleep during the day, not in the night so I thought, once I am hooked on to the peritoneal, I will be losing my sleep. Glucose control For some diabetics, elevated blood sugar from the receipt of PD solution was concerning: 33

43 For peritoneal, the solution that they introduce to the belly, is sugar based so I am diabetic and that sugar based solution can increase my blood sugar level and with hemodialysis, it s the other way. Comfort with existing modality Some patients found comfort in staying with their current dialysis modality: This, I am comfortable to now. I didn t want to change my mind again to go to the other kind. I am now comfortable. Preconceptions Some patients had certain preconceptions and beliefs about health and illness that influenced their decision to select a particular dialysis modality. Specifically, there was a concern that infections associated with PD are more serious and another patient was troubled by the creation of an AVF for HD because of his belief that the artery and venous blood supply should remain separate. The PD infection you have to be careful about that. I don t think the HD is a problem that much with it. I don t know. To connect a vein to an artery, it's against their nature. I mean you connect an oxygenated body of blood with one that should be clear, and in this case you bring toxins to the brain and that s not a good idea. 34

44 Table 3. Quotations from participants to illustrate each theme, mapping to the COM-B system Themes Quotations from participants Capability - physical strength and dexterity / sound mind Your strength to lift this stuff to put on the machine the bags of stuff, then you have to cut these boxes up, lots of boxes, every day you have about two boxes to throw out so you have to take a knife. (PD) You need a good memory to remember the steps of what to do and if the machine fails, you have to be able to switch to the manual bags and things like that. (PD) I realize my hand is not firm like years ago.. when you do manual things with your hands.. I cant do it. (unsure) Opportunity - external forces / constraints Employment Home environment On-time / transportation Support They said that PD would take place all night so that will give him the chance while he s resting he doesn t feel he need to break his day to come here to the hospital all day because he still works. (PD) I am an accountant I have clients From home from office. (HD) It s a lot of boxes to store in your, luckily I have a two bedrooms, so I have some space, but somebody with a one bedroom would have a difficult time. (PD) You could trip easily with all this wiring and everything and spacing of our house is not big, so there are times to trip all the time. It s not a convenient place for what somebody needs, especially with the narrow hallways. (HD) I live far from the hospital, so it be you know, with the winter especially, the snow or something like that, I can t keep it a time you know you have to keep the time exactly for the hospital, so if the weather is bad or something happen and I can t keep it the time. (PD) Wheeltrans is a transportation system that they set up that they pick you up at your home and bring you here and its $2.00 only. They are very reliable and really good. They call you the night before and tell you the time they are going to pick you up and they take me home from the hospital too. (HD) I m always late, suppose I m 2 hours late because I m always late, right? and I come what am I going to do you know now they ll be upset, you know and it s a disadvantage because I ll get sick. (PD) They ll bring the machine at home, they ll bring the supplies at home and there is a 24 hour number in case you want help you call them And on top of that, they will send a nurse to your house to set up the machine 3 to 4 times a week. (PD) 35

45 External influences Normal life Burden Convenience and flexibility I could have the nurse for the rest of my life, or if I m independent, I can have them until I tell myself I can do it on my own, and even though I am doing it on my own, there are mistakes to be made and they are only a stone throw away. (PD) I m a backup definitely I m always going to be there for (spouse) definitely for support and everything and I will be learning how to do the dialysis with (spouse). I ve already learned a lot with changing the dressing too for the catheter because sometimes it gets overwhelming for (spouse) to do all that on (spouse) own, so I think we are going to carry on with trying to do the PD as well. (PD) It s just a fact that the PD, my friend has been on it for so many years, so that might have been encouragement. (PD) I went to my doctor, my general doctor who is a family doctor and I asked her about the two and she suggested that because of my age, it would be safer if I came to the hospital, rather than do it at home. She said to do to it at home, your home is constantly a hospital. (HD) Motivation - values and beliefs So doing it at night time, hopefully when he gets up in the morning he ll start his day as per normal so that s not going to affect his daily routine. (PD) The most important effect is to keep your life and to see which one is the best for maintaining your normal life or much close to normal situation. (PD) My wife has to drop me for hemo, I don t drive. I stopped driving some years now and the time it takes her to come and the time doing the hemo, it s tedious. (PD) I live with a (spouse) who is 74 years old and it will be too much for (spouse) to take care of me. you know.. in the night.. if I am on the peritoneal.. (HD) I live with my daughter and she has 3 kids, one is married now so it s only the two, and to me, it s hard for the family to have somebody like you who needs help and everything so I think I like coming over. (HD) You do it at your convenience. The supplies are brought to you. You have a nurse come if you want for the rest of your life you have support 24 hours a day and what else could you ask for. (PD) To do it at home at night time would be convenient and it would give me free day to do whatever I like to do. In a hospital it wastes my day. I have to come for few hours and you know it ruins my day. That s the main thing. (PD) I guess you have to come a certain time whereas with the 36