Abstract
Background:
Cardiovascular disease is the leading cause of death in kidney transplant recipients. Physical activity after transplant is the most modifiable nonpharmacological factor for improving cardiovascular outcomes. Few studies have tested walking interventions to enhance daily steps and health outcomes in older kidney recipients.
Methods:
Using a pilot feasibility randomized clinical trial design, we tested the feasibility and efficacy of a 6-month SystemCHANGE™ (Change Habits by Applying New Goals and Experience) + Activity Tracker intervention for recruitment, retention, daily steps, and health outcomes (blood pressure, heart rate, body mass index, waist circumference, and physical function). The SystemCHANGE™ + Activity Tracker intervention taught participants to use a multicomponent intervention that connects person-centered systems solutions combined with visual feedback from a mobile activity tracker to achieve daily step goals.
Results:
Fifty-three participants (mean age 65 years, 66% male, and 57% white) participated with 27 in the intervention and 26 in the control group. The study protocol was feasible to deliver with high adherence to the protocol in both groups. The intervention group increased daily steps at 3 months (mean difference, 608; standard error = 283, P = .03) compared to the control group. The secondary outcome of heart rate decreased for the intervention group (baseline [mean] 74.4+ 10.8 [standard deviation, SD;] vs 6 months [mean] 67.6+ 11.3 [SD]; P = .002) compared to the control group (baseline [mean] 70.67+ 10.4 [SD]; vs 6 months [mean] 70.2 + 11.1 [SD]; P = .83).
Conclusions:
SystemCHANGE™ + Activity Tracker intervention appears to be feasible and efficacious for increasing daily steps in older kidney recipients.
Keywords: older adults, physical activity, kidney transplant recipient, activity tracker
Introduction
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in older kidney recipients.1 The effects of aging posttransplant provide a number of challenges for older recipients. These challenges are often linked to the burden of comorbidities (diabetes, hypertension, and obesity) and health decline (cognitive impairment), resulting in decreased quality of life (QOL). Kidney recipients need to adhere to immunosuppressive therapy, which is associated with increased cardiovascular risk and death after transplantation.2 Physical function is a significant predictor of mortality and future hospitalizations in older adults kidney recipients.3 A recent study found that physical inactivity was high in kidney recipients compared to the general population.4
Regular physical activity after kidney transplant is known to have positive effects for improving cardiovascular outcomes.5 Greater physical activity levels are correlated with reduced risks of rapid decline in renal function and mortality risk from CVD.3 Daily walking decreases the risk of CVD in older adults and the more active, risk for CVD decreases.4 Technologies, such as consumer mobile activity trackers, have gained wide popularity to encourage physical activity (eg, walking).6 However, activity trackers alone are insufficient to sustain daily physical activity. Personalized interactive interventions are needed to reinforce the goals for sustaining daily physical activity.
Change Habits by Applying New Goals and Experience (SystemCHANGE™) is an interactive approach that incorporates personalized methods for sustaining personal goals for behavior change.7 SystemCHANGE™ was developed and tested originally to enhance exercise rates in cardiac patients.7 The SystemCHANGE™ paradigm consists of goal-setting, ongoing evaluation from feedback, and making adjustments to achieve one’s goals.8 SystemCHANGE™ has been effective for influencing behavior change in previous research studies for adults with chronic disease: after a cardiac event (exercise),7 stroke (healthy eating and exercise),9 HIV (sleep),10 and post-kidney transplant (medication adherence).11
Transplant recipients reported setting personal goals an important behavior change facilitator for performing physical activity.12 As such, we combined the paradigm of SystemCHANGE™ with the use of a mobile activity tracker to increase physical activity in older kidney recipients. Therefore, the purpose of this study was to test and evaluate an intervention called, SystemCHANGE™ + Activity Tracker intervention. The first aim of this study was to evaluate the pilot feasibility for recruitment and retention. The second aim was to test the efficacy of our intervention on daily steps. The third aim was to determine the efficacy of the intervention on health outcomes, at baseline, 3, and 6 months.
Materials and Methods
Study Design
We conducted a pilot feasibility study using a randomized controlled trial (RCT) parallel design. Institutional review board approval was obtained prior to the initiation of the study activities. All participants provided signed informed consent. After informed consent was obtained, the participants were randomized 1:1 to either the intervention arm or an attention-control arm using a permuted block randomization scheme generated by the study statistician. Participants and research assistants were masked to the group assignment.
Setting and Sampling
The accessible population were participants recruited from a Midwest transplant center during January to September 2018 using a convenience sampling strategy. The transplant center functions as a regional referral center and serves a racially diverse population from both urban and rural communities. The transplant center performs over 200 kidney transplants each year.
Population
The demographics of the accessible patient population are that 51% of the patients are over 50 years of age. Of these 51% patients, 52% are white males, and the primary renal diagnosis at the time of transplant was diabetes mellitus type II (80%) and hypertensive nephrosclerosis (80%).13
We used these recruitment strategies to recruit the sample (a) face-to-face contact in the transplant clinic, (b) paper flyers placed in the clinic, (c) Facebook, (d) an online newsletter for kidney transplant recipients who were enrolled as volunteers for a local organ and procurement organization associated with the transplant clinic, and (e) a university website listing of research studies. Potential participants who expressed interest in the study were scheduled to meet with the research team to explain the study, answer questions, and solicit consent to participate in the study. If verbal agreement was obtained, inclusion/exclusion criteria were reviewed and a cognitive screening test using the 6-item cognitive exam screener14 was administered to the potential participant. Those eligible for the study signed the informed consent. The enrolled study participant was then scheduled for the first group meeting session.
Inclusion criteria included age 60 years or older, functioning kidney transplant (not on dialysis), ability to speak English, possession of a smartphone, no use of assistive devices for walking (activity trackers require movement of the arms and legs), and ≥3 months posttransplant. Exclusion criteria were participating in a weight loss program or structured exercise program, currently using an activity tracker, unable to pass a brief cognitive screening test, or planning to move out of the area within the next 6 months (Figure 1).
Figure 1.
Study screening, enrollment, randomization, and completion groups.
Data Collection
Variables collected.
The primary aim was to evaluate the feasibility for recruitment and retention. Feasibility was measured as meeting recruitment targets, participant adherence to monthly meetings, ability to deliver the SystemCHANGE™ and attention control interventions in-group settings, goal setting in the intervention group, and participant adherence to wearing the activity tracker. Sociodemographic and clinical variables were collected to describe the study sample.
The second aim was to test the efficacy of a SystemCHANGE™ + activity tracker intervention on increasing daily steps. The number of daily steps, as recorded by Fitbit Charge 2, measured the efficacy of the intervention for increasing daily steps. This device has demonstrated high degrees of accuracy.15
The third aim was to determine the efficacy of the intervention on health outcomes. These health outcomes included resting blood pressure (BP) and heart rate (HR), body mass index (BMI), waist circumference (WC), and physical function (six-minute walk test [6MWT]). These health outcomes were measured at baseline, 3 months, and 6 months. Resting BP and HR were measured while the participant was in a seated position using a wireless Withings BP cuff. Physical function was assessed by the 6MWT. The 6MWT has demonstrated high test–retest reliability for older patients.16
Process of data collection.
All study data were entered directly by study participants and research assistants using electronic research forms via a password protected tablet using Research Electronic Data Capture (REDCap), at baseline, 3, and 6 months. Average steps per day (monthly averages), health outcomes, and physical function were collected at baseline, 3, and 6 months. Activity tracker data (steps) was synced daily to the Fitabase system.
Statistical Analysis
All analyses were conducted using SPSS version 24 (IBM SPSS). Due to the pilot nature of the study, sample size (N = 60, 30/arm) was determined based on the anticipated feasibility of recruitment within the study budget and timeline rather than sufficient statistical power. Post hoc power analysis suggested our sample size had 43% power to detect a medium effect size of 0.5 for between-group difference and 69% power to detect a medium effect size of 0.5 for within-group difference at a 2-sided significance level (α) of .05.
Descriptive statistics were conducted on all variables. Group comparisons of baseline demographic and clinical characteristics were conducted with bivariate tests (T test, χ2, or exact χ2) as appropriate. Descriptive frequency statistics were used to evaluate the primary aim for feasibility for recruitment and retention. An intent-to-treat analysis was used to address study aims 2 and 3. For the number of daily steps, mixed-effects linear regression modeling was used to model the daily steps as a linear combination of the fixed-effects of the group (intervention vs attention-control), months (baseline and months 1–6), and group by months interaction, adjusting for within-subject clustering of daily repeated measures using subject-specific random intercepts with a first-order autocorrelation. From the model, we derived estimates on the (1) average daily steps for each group in each month, (2) between-group comparisons (intervention vs attention-control) of the average daily steps for each month, and (3) between-group comparisons of the change in average daily steps from baseline at months 1 to 6. Similarly, we used mixed-effects linear regression modeling to derive estimates for each health outcome BP, HR, BMI, WC, and 6MWT. These estimates included (1) group-specific means at each time point (baseline, 3-months, and 6-months), (2) between-group comparisons of the mean outcome at each time point, and (3) between-group comparisons of change from baseline at 3-months and 6-months. The mixed-effects modeling analyzed all available data and accommodated for missing random data.
Procedure Overview
Intervention and attention-control groups both received a Fitbit Charge 2. Both groups were enrolled in the study in the same manner, received the same baseline instruction on the use of the activity tracker, and had the same number of study contacts (baseline and 6 monthly group sessions). Participants in both groups were encouraged to wear the activity tracker every day and were provided with a phone number if technical support was needed. The group sessions consisted of 3 to 5 participants. The difference between the 2 group sessions was that the intervention group received instructions for using the SystemCHANGE approach combined with an activity tracker to increase daily steps and the attention-control group received only transplant educational information about self-care after transplant with an activity tracker to track daily steps. The attention-control group did not receive the SystemCHANGE™ approach. The procedure for each group is described below.
Treatment dose (ie, time taken to deliver the materials) was evaluated across all sessions for both groups. Step data from the participant’s smartphone were synchronized daily into the password-protected Fitbit app and into Fitabase using Bluetooth technology. The step data from Fitabase were downloaded directly into the Excel for upload into SPSS.
Participant retention was addressed through scheduled meetings, incentives, and ongoing contact. At the baseline session, the schedule for monthly group face-to-face sessions was entered in their smartphone calendars. Participants were given gift cards for completing baseline and each monthly session.
Description of the intervention.
SystemCHANGE™ + Activity Tracker intervention is a multicomponent intervention that connected person-centered systems solutions that individuals have already established in their lives, such as daily routines, events, and circumstances within their personal environment. The personal system-based solutions support and enhance physical activity combined with visual feedback from a mobile activity tracker. SystemCHANGE™ + Activity Tracker intervention focuses on guiding individuals to incorporate the desired behavior change as part of their daily or weekly routines. For example, if a person’s goal is to increase daily steps and their daily routine is driving to work, a SystemCHANGE™ solution to increase daily steps would be to park the car farther away from the building where they work so they walk a longer distance.
The SystemCHANGE™ + Activity Tracker intervention consists of 4 steps. Step 1: The participants identified important people who influenced their physical activity. Step 2: The participants identified routines that occur daily, weekly, or monthly, focusing on the impact of these routines on physical activity. Step 3: The routines identified in step 2 were placed into a graphic format cycles figure. The cycles figure helped the participant understand how routines relate to each other and how they can work for or against changing physical activity behavior. Step 4: The participant identified a personal system-based solution. If greater personal motivation was required, the participants were guided in identifying another personal system-based solution. These steps were implemented during the monthly group sessions.
In the monthly sessions, participants reviewed their activity tracker report with the research team. During each session, participants were asked, “Tell me what you are learning about physical activity, and do you think the changes that you have made are impacting your physical activity levels?” If changes were, the participant would identify another personal system-based solution. The research team would add 5% to the average obtained from the participant’s previous month step goal as the new monthly goal for each participant.
Training of the research team.
All research staff were trained by a SystemCHANGE™ expert. The research assistants completed 6 simulated participants until 100% competency was demonstrated.
Description of attention-control.
The attention-control group participants received transplant educational materials to help them learn more about healthy self-care after transplant. Monthly topics were presented each month and included diet and exercise, medication adherence, risk for skin cancer, gastrointestinal side effects, dental care, and posttransplant diabetes. Participants in the attention-control group were not asked to increase their step goal each month or to review their activity tracker report.
Treatment Fidelity
A protocol checklist ensured standardized delivery of the protocol. The checklist included all steps needed to complete each session and a log of time taken for each session. To determine participant understanding of the intervention, each participant was assessed on their monthly progress for using the activity tracker via the activity tracker reports generated via Fitabase. The attention-control group understanding of the research activities was determined by the participants stating their comprehension of the transplant educational information delivered each month.
Results
We contacted 424 kidney recipients, age 60 years and older. Of those, 206 agreed to be screened for the study (Figure 1) and 60 (30%) met inclusion requirements and were enrolled in the study. The primary reason participants were excluded from the study was (n = 91, 62%) they used an assistive device for walking (cane or walker). Many participants declined to participate in the study because they lived greater than 2 hours away from the meeting site for the group sessions. Thirty participants were randomized to both the intervention group and to the attention-control group.
Feasibility
We met our recruitment target of 60 participants. Reasons for attrition were related to disease progression and declining health. The final sample consisted of 27 participants in the intervention group and 26 in the control group. Both groups were similar in demographic variables (Table 1). Six-month study attrition rate was 17%. Adherence for attendance to monthly group meetings in the intervention group was 93% and 96% in the control group. The group session contacts were equivalent (60 minutes) in both groups. In the intervention group, 100% of the participants who started the study were able to implement a daily step goal and personalized solutions for achieving daily steps and 100% wore the activity tracker consistently for 6 months. In the attention-control group, 2 participants did not wear the activity tracker consistently for 6 months. No deviations were found in the research team delivering the protocol from baseline to 6 months.
Table 1.
Profile of Participants in the Intervention and Attention-Control Groups.
| Mean (SD) or N (Column %) | |||
|---|---|---|---|
| Variables | Intervention (N = 27) | Attention-control (N = 26) | P |
| Age in yearsa | 65.7 (SD, 4.9) | 65.1 (SD, 4.0) | .59 |
| Genderb | .29 | ||
| Male | 16 (59) | 19 (73) | |
| Ethnicityc | .49 | ||
| Non-Hispanic | 27 (100) | 25 (96) | |
| Hispanic | 0 (0) | 1 (4) | |
| Racec | .54 | ||
| White | 16 (59) | 14 (54) | |
| Black | 10 (37) | 10 (38) | |
| Other | 1 (4) | 2 (8) | |
| Educationc | .99 | ||
| No HS or GED | 1 (4) | 1 (4) | |
| HS or GED | 11 (41) | 9 (35) | |
| Associates or Higher | 15 (55) | 16 (61) | |
| Incomec | .52 | ||
| <US$20 000 | 2 (7) | 3 (12) | |
| US$20 000 or greater | 25 (93) | 21 (80) | |
| Prefer not to say | 0 | 2 (8) | |
| Number of people in the householdc | .64 | ||
| One | 5 (19) | 4 (15) | |
| Two | 17 (63) | 19 (73) | |
| Three or more | 5(18) | 3 (12) | |
| Employment statusc | .46 | ||
| Full-time employment | 9 (33) | 8 (31) | |
| Part-time employment | 3 (11) | 0 (0) | |
| Retired | 12 (45) | 16 (62) | |
| Other | 3 (11) | 2 (7) | |
| Years since last kidney transplanta | 7.0 ± 5.7 | 7.2 ± 6.5 | .93 |
| Primary cause for kidney failure (self-reported)c | |||
| High blood pressure (only) | 6 (22) | 7 (27) | .85 |
| Diabetes (only) | 6 (22) | 5(19) | |
| Diabetes and high blood pressure (both) | 1 (4) | 3(12) | |
| Not sure | 2 (7) | 2 (8) | |
| Other | 12 (44) | 9 (35) | |
| Caregiverc | .50 | ||
| Self | 19 (70) | 16 (62) | |
| Spouse or partner | 7 (26) | 7 (27) | |
| Other | 1 (4) | 3 (11) | |
Abbreviations: SD, standard deviation; HS, High School; GED, General Educational Development.
Two-sample t tests were used for continuous variables (age and years since last kidney transplant).
The χ2 test was conducted for gender.
Exact χ2 tests were used for categorical variables that had more than 20% of the cells with expected counts less than 5, including ethnicity, race, education, income, number of people in the household, employment status, primary cause for kidney failure, and caregiver.
Efficacy of the Intervention on Daily Steps
At baseline, the intervention and attention-control groups recorded a similar number of daily walking steps (mean = 4227 [standard error, SE = 552] vs mean = 4171 [SE = 563], respectively, P = .72). Throughout the following months, the intervention group participants consistently increased their average number of daily steps. The attention-control group showed a slight increase in the first 2 months that then declined and returned to baseline levels by 6 months. The intervention group increased daily steps at 3 months (mean difference, 608 [SE = 283], P = 0.03) and 6 months (mean difference, 479 [SE = 283], P = 0.09) compared to the attention-control group (Table 2).
Table 2.
Kidney Transplant Recipients 60 and Older Average Daily Steps in the Intervention Versus Attention-Control Groups.
| Time | Intervention Mean (SE) | Attention-control Mean (SE) | Intervention versus attention-control | Change from baseline, intervention versus attention control | ||
|---|---|---|---|---|---|---|
| Mean diff. (SE) | P | Mean diff. (SE) | P | |||
| Baseline | 4427 (552) | 4171 (563) | 285 (789) | .72 | - | - |
| Month 1 | 5139 (533) | 4865 (543) | 274 (761) | .72 | −11.04 (281.76) | .97 |
| Month 2 | 5511 (533) | 4936 (543) | 575 (761) | .45 | 290.37 (281.76) | .30 |
| Month 3 | 5674 (533) | 4710 (543) | 893 (761) | .24 | 607.65 (282.64) | .03 |
| Month 4 | 5346 (533) | 4588 (543) | 687 (761) | .37 | 401.76 (282.64) | .16 |
| Month 5 | 5436 (533) | 4566 (543) | 798 (761) | .29 | 513.20 (282.64) | .07 |
| Month 6 | 4993 (533) | 4157 (543) | 765 (761) | .32 | 479.48 (282.64) | .09 |
Abbreviation: SE, standard error.
Efficacy of the Intervention on Health Outcomes
Both groups demonstrated high systolic BP at baseline and 3 and 6 months (Table 3). The systolic BP of the attention-control group improved from baseline to 6 months while the intervention group remained the same. After 6 months, there were no differences between the groups for systolic BP (Table 3). Diastolic BP remained unchanged in both groups. Resting HR decreased from baseline to 6 months for the intervention group (mean 74.4 bpm [standard deviation, SD 10.8]; vs 67.6 bpm ± 11.30; P = .002), while it remained unchanged for the attention-control group (mean 70.7 bpm [SD 10.4]; vs mean 70.2 bpm [SD 12.1]; P = .83). The between-group comparison indicated the intervention group had a 6.3 mean average decrease in resting HR from baseline to 6 months when compared to the attention-control group (P = .04). Both groups experienced a reduction in weight, WC, and BMI from baseline to 6 months. The intervention group and the attention-control group had similar improvements in 6MWT over 6 months of the trial.
Table 3.
Health Outcomes and Physical Function in the Intervention and Attention-Control Groups, by Time (Baseline, 3 Months, and 6 Months).
| Change from baseline | |||||||
|---|---|---|---|---|---|---|---|
| Baseline | 3 Months | 6 Months | 3 Months versus baseline | 6 Months versus baseline | |||
| Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | P | Mean (SD) | P | |
| Systolic BP (mm Hg) | |||||||
| Intervention | 141.8 (24.2) | 140.7 (26.54) | 143.3 (19.69) | −1.08 (28.21) | .85 | 1.52 (20.92) | .72 |
| Attention-control | 150.2 (19.05) | 146.7 (18.61) | 142.2 (12.76) | −3.52 (17.34) | .32 | −7.96 (19.11) | .05 |
| Intervention vs attention-control | 2.44 (23.41) | .71 | 9.48 (20.04) | .10 | |||
| Diastolic BP (mm Hg) | |||||||
| Intervention | 80.16 (14.82) | 79.52 (14.47) | 78.80 (13.10) | −0.64 (13.80) | .82 | −1.36 (13.75) | .63 |
| Attention-control | 79.64 (10.02) | 80.52 (12.73) | 77.20 (8.94) | 0.88 (12.06) | .72 | −2.44 (7.85) | .13 |
| Intervention vs attention-control | −1.52 (12.96) | .68 | 1.08 (11.20) | .73 | |||
| HR (bpm) | |||||||
| Intervention | 74.36 (10.83) | 69.08 (8.82) | 67.56 (11.30) | −5.28 (8.19) | .004 | −6.80 (9.77) | .002 |
| Attention-control | 70.68 (10.36) | 70.20 (12.11) | 70.20 (11.11) | −0.48 (10.14) | .81 | −0.48 (10.87) | .83 |
| Intervention vs attention-control | −4.80 (9.22) | .07 | −6.32 (10.34) | .04 | |||
| Weight (pounds) | |||||||
| Intervention | 189.4 (36.30) | 188.5(37.11) | 186.6 (37.67) | −0.86 (5.02) | .40 | −2.76 (9.05) | .14 |
| Attention-control | 194.9 (40.84) | 193.1 (36.63) | 192.6 (36.06) | −1.83 (9.66) | .35 | −2.34 (7.88) | .15 |
| Intervention vs attention-control | 0.97 (7.70) | .66 | −0.42 (8.48) | .86 | |||
| WC (inches) | |||||||
| Intervention | 40.54 (5.21) | 39.22 (5.00) | 38.68 (5.02) | −1.32 (1.71) | <.001 | −1.86 (1.91) | <.001 |
| Control | 40.94 (5.13) | 39.76 (5.24) | 39.08 (4.92) | −1.18 (2.10) | .009 | −1.86 (1.88 | <.001 |
| Intervention vs attention-control | −0.14 (1.91) | .80 | 0.00 (1.90) | 1.00 | |||
| BMI | |||||||
| Intervention | 31.42 (6.02) | 31.28 (6.08) | 30.68 (6.44) | −0.14 (0.86) | .42 | −0.74 (1.39) | .01 |
| Attention-control | 30.29 (5.24) | 30.28 (5.53) | 29.48 (4.55) | −0.01 (2.59) | .99 | −0.81 (1.22) | .003 |
| Intervention vs attention-control | −0.13 (1.93) | .81 | 0.07 (1.31) | .85 | |||
| 6MWT (feet) | |||||||
| Intervention | 1139 (231.0) | 1158(235.9) | 1142 (295.0) | 18.64 (145.10) | .53 | 3.10 (205.49) | .94 |
| Attention-control | 1115 (290.1) | 1142 (337.1) | 1204 (266.6) | 27.10 (321.97) | .68 | 93.63 (50.70) | .006 |
| Intervention vs attention-control | −8.46 (249.72) | .91 | −90.53 (180.76) | .09 | |||
Abbreviations: 6MWT, 6 minute walk test; BMI, Body Mass Index; BP, blood pressure; HR, heart rate; SD, standard deviation; WC, waist circumference.
Discussion
Daily walking has multiple health benefits for improving body composition, BP, lipid profile, and various aspects of QOL in older adults. There is mounting evidence that decreasing sedentary time and increasing physical activity in older adults is effective for decreasing cardiovascular events and risks for other physical and mental events.17,18 Few studies have specifically focused on walking interventions for older kidney recipients. Our pilot feasibility study is the first RCT to test the SystemCHANGE™ + Activity Tracker intervention designed to engage older recipients to increase their physical activity via daily walking steps.
The study was feasible to conduct although 65% of the participants approached to be in the study declined because they lived greater than 2 hours away. This finding indicates there is a need to consider delivering the intervention in home settings. We found that older recipients who received the intervention showed a trend for increasing the number of daily steps and lowering their resting HR. Overall, the intervention group maintained a higher number of daily steps from baseline to 6 months with the average number of steps decreasing after 3 months. Perhaps this drop in the number of daily steps after 3 months is best explained by what some researchers have called the novelty effect. The novelty effect is defined as a person’s first performance when using new technology in response to the level of interest, not the performance that will persist over time as the product ceases to be new to the person.19 Other studies have suggested using at least 3 personalized monthly booster sessions by phone or text messaging to give feedback and support to sustain physical activity.20,21 In our study, we met each month face-to-face with the participants in a group setting and provided them with an incentive gift card. For the future, we should consider providing additional personal booster to provide encouragement.
Beyond increasing daily steps, other measures of reducing cardiovascular risk may be important in this patient population. For example, the finding of reducing resting HR of 6.3 beats per minute in the intervention group as compared to the control group may also be clinically meaningful. A seminal study found that a resting HR of 70 bpm or less was associated with fewer deaths per year.22 Further, monitoring resting HR over time as a biomarker may be useful in identifying individuals with the greatest risk for a cardiovascular event.23
While our intervention was successful with increasing the number of daily steps and reducing resting HR, little effect was found with other health. Similar findings were found in a systematic review conducted by Didsbury and colleagues,24 as little effect was observed in BP among solid organ transplantation recipients who participated in regular, daily exercise. The literature indicates that there is no clear consensus on the effects of exercise and BP in kidney recipients.25 Despite these findings, physical activity, such as walking, is safe low risk for activity and is associated with improved QOL.26
Our study has limitations. First, the sample was from a single-site transplant center. Second, the sample size was small, although the data are encouraging. Third, over 62% of recipients were excluded from the study due to the use of assistive devices used for walking. Future research should consider the best approaches for including older adults with mobility issues to help these older adults increase and monitor their daily activity. Last, we did not ask the participants if they had a diagnosis of hypertension and taking antihypertensive medication; therefore, we were unable to control for this in the analysis. It is possible that more participants in the intervention group were taking antihypertensive medication so little change in BP was observed. Despite these limitations, our sample was representative of older kidney recipients in the United States where 53% are white males, aged 65 years and older.13
A longitudinal RCT is needed to test how this intervention influences cardiovascular outcomes, frailty, cognitive decline, and depression among older recipients. Because older recipients are vulnerable to cognitive decline based upon their age, chronic disease burden, and effects of multiple medication interactions,27 modifying this intervention to include those persons who may have mild cognitive impairment is another avenue that is rich for further study.
Conclusion
In this sample of older kidney recipients, we found the SystemCHANGE + Activity Tracker intervention was feasible and efficacious for promoting adherence to a walking intervention and increasing daily steps. These findings are important, given the number of older recipients who are not physically active and are at a high risk for developing multiple chronic conditions. The intervention appears promising for increasing activity among older kidney recipients that could be used in future practice.
Supplementary Material
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study was funded by the National Nursing Institute for Nursing Research (NINR), (7K23NR016274-02) and The Ohio State University Center for Clinical and Translational Science grant support (National Center for Advancing Translational Sciences), (Grant 8UL1TR000090-05).
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
ClinicalTrials.gov Identifier NCT03191630. Date of Clinical Trial June 19, 2017. Link to Clinical Trial: https://clinicaltrials.gov/ct2/show/NCT03191630. IRB Approval: The Ohio State University Behavioral and Social Sciences Institutional Review Board, Study Number: 2017B0084.
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