INTRODUCTION

Adhering to disease self-management recommendations is essential for patients with chronic kidney disease (CKD) not receiving dialysis, including kidney transplant recipients (1). However, many do not succeed in achieving recommended behavioral goals for nonsmoking, physical activity, weight maintenance, and adherence to medication prescriptions or dietary recommendations (2,3): about 50% of individuals with CKD show suboptimal adherence (4).

Evidence on intervention effectiveness in enhancing self-management in this population is promising but limited (5). For instance, in two recent trials that evaluated dietary interventions, patients were able to successfully reduce their sodium excretion, but effects diminished over time (6,7). A possible explanation for the lack of sustained effects may be that interventions only address self-management behaviors directly, with limited attention for psychological complaints that may hinder behavior change (8). Psychological distress, often assessed as depressive or anxiety symptoms, may come along with problems in motivation, lack of energy and self-efficacy, pessimistic cognitions, and social withdrawal, which could all form barriers to self-management (8–10). Vice versa, suboptimal self-management may induce psychological distress, for instance, by diminished physical and social activity, reduced physical fitness, or negative perceptions toward oneself regarding nonadherent behaviors (8–10). Accordingly, psychological distress has been associated with suboptimal self-management among patients with CKD (11). These mechanisms are alarming because both factors have been related to adverse health outcomes, including disease progression, accelerated initiation of dialysis, and mortality (3,12).

Therefore, the psychological distress symptom prevalence of 13% to 34% among patients with CKD not on dialysis is concerning for patients’ psychological and physical health (12,13). Intervening advocates multicomponent approaches, focused on bidirectional improvements in psychological functioning and self-management. Literature suggests that such combined interventions could be more effective than one-sided treatments in improving health outcomes (9,14). To our knowledge, no literature exists regarding interventions that synergistically target both psychological distress and CKD self-management among patients not on dialysis.

Next to incorporating treatment of psychological distress in self-management interventions, the importance of patient-tailoring is also increasingly being emphasized (15,16). Person-centered care—tailored to individual needs, wishes, and goals—has been associated with enhanced patient satisfaction, quality of life, psychological and physical outcomes, and self-management skills (17). In the E-GOAL study, we designed a personalized and blended electronic health (eHealth) care pathway (18). Personalization was deployed in three ways: first, a screening tool with personalized feedback was used to identify patients with psychological distress and suboptimal self-management, to offer treatment only to people who needed it, and to determine patients’ personal priorities for intervention (16). Second, in guided Internet-delivered cognitive-behavioral therapy (iCBT) with self-management support, patients could choose their preferred goals, eHealth modules, delivery modes, and time investment, making the intervention personally relevant, feasible, and acceptable (19). Last, because patients focused on distinct, personally meaningful goals, they likely improved on different outcomes. Therefore, we included personalized outcome measures (Tommel et al., 2022, unpublished).

The primary aim of this multicenter randomized controlled trial (RCT) was to investigate the effectiveness of the E-GOAL personalized iCBT intervention in reducing psychological distress at posttest directly after the intervention and at 3-month follow-up among patients with CKD not on dialysis compared with a care as usual control condition. We hypothesized larger improvements in the intervention group than in the control group on psychological distress and on secondary outcomes physical and mental health-related quality of life (HRQoL), self-efficacy for disease management, chronic condition self-management (i.e., engaging in health-promoting behaviors, managing symptoms, coping with impacts on functioning, and adhering to treatment; (20)), and perceived progress on personally prioritized areas of functioning (PPP-functioning) and self-management (PPP self-management) (Tommel et al., 2022, unpublished) at posttest that would be sustained till follow-up. For the latter, personalized outcomes, we expected no worsening within-group at follow-up, which would indicate that possible intervention effects remained stable. Last, to better understand the effectiveness of the intervention on the composite psychological distress, we explored effects on its separate components depressive and anxiety symptoms.

METHODS Trial Design

E-GOAL was an open RCT with two parallel groups (allocation ratio 1:1), conducted from April 2018 to October 2020. The study was approved by the Medical Ethics Committee of Leiden University Medical Center (P17.172), is registered at the Netherlands Trial Register (NTR7555), and complies with the 1964 Declaration of Helsinki. The Consolidated Standards of Reporting Trials statement (Supplemental Digital Content [SDC] 1, Table S1, https://links.lww.com/PSYMED/A888) and the Template for Intervention Description and Replication checklist were used for reporting (21,22).

Participants

Recruitment and data collection took place at nephrology departments of three university hospitals and one general hospital in the Netherlands: Leiden University Medical Center, University Medical Center Groningen, Radboud university medical center, and Haaglanden Medical Center. Patients with CKD not receiving dialysis were recruited in two phases. In the screening phase, patients were invited to complete screening questionnaires regarding psychological distress and self-management. In the randomization phase, only patients whose screening results indicated that they could benefit from the intervention were invited to participate in the RCT (Box 1 depicts all inclusion and exclusion criteria by phase).

Box 1. Inclusion and Exclusion Criteria.

Criteria screening phase

 Inclusion criteria

Under medical treatment by an internist-nephrologist Chronic kidney disease with an eGFR 20–89 ml/min per 1.73 m2 ≥18 years old Sufficient command of the Dutch language Able to give informed consent Access to a computer or tablet with Internet

 Exclusion criteria

Rapidly progressive renal function loss (>10% renal function loss over the last year) Anticipated need for dialysis work-up within the time frame of the study Systolic blood pressure <95 mm Hg not responding to withdrawal of antihypertensive medication Medical conditions that are likely to interfere with study completion (e.g., progressive malignancy, recent cardiovascular event, severe psychiatric disorders) at the discretion of the nephrologist Kidney transplantation <1 year ago Difficulties in (written) communication (e.g., due to analphabetism) Pregnancy

Criteria randomization phase

 Inclusion criteria (increased-risk profile)

At least mild depressive or anxiety symptoms (PHQ-9 ≥5 or GAD-7 ≥ 5; (23,24)) AND At least one suboptimal self-management outcome (<150 minutes per week of moderate-to-vigorous intensity physical activity,a a body mass index ≥25 kg/m2,b tobacco smoking ≥1 unit per day,c dietary or medication nonadherence based on questionnaire cutoff points)d,e (1)

 Exclusion criteria

Severe depressive or anxiety symptoms (PHQ-9 ≥20 or GAD-7 ≥15; (25)) Ongoing psychological treatment elsewhere

eGFR = estimated glomerular filtration rate; PHQ-9 = Patient Health Questionnaire Depression Scale; GAD-7 = Generalized Anxiety Disorder scale.

a Short Questionnaire to Assess Health-enhancing physical activity (26).

b Ratio of body weight (in kilograms) and square of height (in meters).

c “Do you smoke?” and “How much do you smoke on average per day?”

d “In the past week, how often have you kept a healthy diet?” with scores on a 1–5 scale from “never” to “always” (cutoff for inclusion ≤3) or “In the past week, how well do you believe you have kept a healthy diet?” on a 1–10 scale from “very badly” to “very well” (cutoff for inclusion ≤6).

e Simplified Medication Adherence Questionnaire (cutoff for inclusion ≥2 items indicating nonadherence; (27)).

Potentially eligible patients were invited to participate in the screening phase via their nephrologist. They received verbal and written information regarding study purposes and procedures, with informed consent forms. Upon obtaining written consent, we sent patients emails with a link to online screening questionnaires in the secured eHealth application “PatientCoach” (28). Paper-and-pencil questionnaires were available for patients who had difficulties with online completion. With a brief screening, patients with increased-risk profiles—who experienced at least mild depressive or anxiety symptoms and at least one suboptimal self-management behavior—were automatically detected. These patients were invited to complete complementary questionnaires, assessing specific areas of behavioral, psychological, social, and physical functioning as baseline measurements and to tailor the intervention to personal needs in case they would be randomized to the intervention group. All participants could instantly review digital Personal Profile Charts: visual representations of their questionnaire results (see Figure 1 for an example). They also received paper versions by mail, including a letter to inform patients whether they were eligible for randomization: patients with increased-risk profiles received study information and a second informed consent form (16). Patients without increased-risk profiles were informed that they were not eligible for the RCT. In addition, patients with severe psychological distress were not eligible either. They were contacted by telephone and advised to approach their general practitioner for further evaluation.

FIGURE 1: A and B, Examples of Personal Profile Charts at (A) one time point and (B) progress over time. Traffic light colors indicated current status on domains of functioning and self-management. Additional explanations were shown when hovering the mouse cursor over a domain. Color image is available only in online version www.psychosomaticmedicine.org.Intervention

All patients received Personal Profile Charts in addition to care as usual in line with common practice in patients’ medical center. After randomization, participants in the intervention group additionally received tailored and therapist-guided iCBT including self-management support. The intervention was adapted for patients with lifestyle-related chronic diseases including CKD (18) from an existing iCBT for coping with chronic somatic disease, which is developed from evidence-based face-to-face CBT and has been evaluated among different patient populations (29,30). The intervention had the aims to treat psychological distress, diminish psychosocial barriers and promote facilitators for adherence to self-management recommendations, and support patients in adopting and maintaining healthy and adherent behaviors. Treatment was guided by therapists, that is, health psychologists who received training specific to this trial and attended weekly meetings with a skilled CBT supervisor and registered clinical psychologist.

At the start of treatment, a therapist conducted a face-to-face intake session (±90–120 minutes) with an individual patient, which took place in the patient’s medical center—one video call took place because of COVID-19 measures. The initial session included an assessment of a patient’s physical, psychological, and social functioning, guided by the Personal Profile Charts and screening results (16). Therapist and patient discussed which psychosocial difficulties hindered relevant self-management behaviors, explored patient’s resources that could facilitate change, and determined priorities for improvement. With this information, the therapist aided the patient in formulating two to three personally relevant goals, of which at least one was related to improving psychosocial functioning and one to improving self-management. Also, eHealth application “E-coach” was introduced (25,30). See Figure 2 for an example of modules in E-coach and SDC 2, Table S2, https://links.lww.com/PSYMED/A889, for an overview of all modules.

FIGURE 2: An example of modules in eHealth application “E-coach.” eHealth = electronic health. Color image is available only in online version www.psychosomaticmedicine.org.

During the next 3 to 4 months (approximately), each patient in the intervention condition systematically went through a personalized selection of E-coach modules, which entailed an introduction module and several treatment modules matching personal goals (e.g., modules regarding mood improvement, social functioning, coping with fatigue, and self-management behavior change). Modules included psychoeducational information and exercises based on cognitive-behavioral (e.g., thought record, activity scheduling; (31)) and behavior change techniques (e.g., pros and cons, action planning; (32)). Each patient worked through modules at home and received weekly or biweekly feedback from their therapist via a secured message box within E-coach (±6–16 therapist messages). If needed, treatment was complemented with telephone or face-to-face appointments. After completing personalized modules, the patient went through a final module about relapse prevention and long-term goals. In this module, among other things, each patient wrote a letter to themselves regarding their achievements. Afterward, they had a final telephone appointment (±15–30 minutes) with their therapist to evaluate treatment. Three months later, they received an email from their therapist with their letter to themselves, to maintain goal behaviors. The exact duration of a trajectory was tailored to treatment goals and adequate pace for each individual. Precise details of the development and content of the eHealth care pathway have been published elsewhere (18).

Data Acquisition and Outcomes

Data were collected at baseline, at posttest directly after the intervention, and at follow-up 3 months after posttest. Participants completed online screening questionnaires before randomization for sociodemographic, psychosocial, and behavioral data. All participants received Personal Profile Charts with their results at each time point. Furthermore, randomized participants were invited for medical measurements (weight, waist circumference, and blood pressure) in their medical center at all time points, carried out by trained research nurses or physician researchers. These measurements were documented in a secured online Case Report Form together with medical and biochemical data (e.g., from 24-hour urine and blood samples) extracted from hospital information systems. Adverse events were recorded in digital standardized forms to the Medical Ethics Committee in accordance with standard procedures.

Primary outcome was psychological distress, measured with the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS; (33)), a composite of depressive (Patient Health Questionnaire Depression Scale [PHQ-9]; (23)), and anxiety symptoms (Generalized Anxiety Disorder scale [GAD-7]; (24)). Scores range from 0 to 48, with higher scores indicating higher psychological distress. The PHQ-ADS composite was reliable with Cronbach α values of .78, .85, and .88 at baseline, posttest, and follow-up, respectively.

Several secondary outcomes were assessed. Physical and mental HRQoL were measured with the RAND 36-item Short Form Health Survey (34). Physical and mental HRQoL component summary scores range from 0 to 100, with higher scores indicating better HRQoL. Cronbach α values per time point were .73, .77, and .82 for physical HRQoL, and .74, .78, and .78 for mental HRQoL. Self-efficacy for disease management was measured by the Chronic Disease Self-Efficacy Scales–Manage Disease in General Scale (35). Scores range from 5 to 50, with higher scores indicating stronger belief in the capability of managing disease. Cronbach α values were .83, .82, and .87. Chronic condition self-management was assessed using the Partners in Health scale (20). Scores range from 0 to 96, with higher scores indicating better self-management. Cronbach α equaled .78, .81, and .81. For personalized outcomes (PPP-functioning and PPP-self-management), participants indicated their perceived progress on seven areas of functioning (i.e., fatigue, pain, itch, anxiety, depression, social environment, and daily activities) and five areas of self-management (i.e., medication adherence, healthy diet, physical activity, weight maintenance, and nonsmoking) at posttest and follow-up, with the Personalized Priority and Progress Questionnaire (PPPQ) (Tommel et al., 2022, unpublished). From the original 13-item personalized instrument, items (areas) can be added or removed depending on their relevance for the population under study. An example used in this study is the following: “Compared to the last time I completed this questionnaire, I have managed less well/better to eat healthily.” Per item (area), scores range from −3 (“much less well”) to +3 (“much better”), on which 0 indicates neither worsening nor improvement (“equally well”). At baseline, all participants could indicate a maximum of two areas of functioning and two areas of self-management as personal priorities for improvement. If a participant had indicated one personal priority, the personalized outcome at follow-up entailed the perceived progress score on this indicated item, and if a participant indicated two priorities, their mean was the personalized outcome. The PPPQ was evaluated in two kidney disease samples, showing to be feasible and easy to complete in 2 to 4 minutes. The questionnaire items showed acceptable construct validity and few floor or ceiling effects. Also, in the current study, the scales showed acceptable to good internal consistency with Cronbach α values of .88 and .83 at posttest and follow-up for functioning, and .69 and .73 for self-management. Development and validation of the PPPQ have been further described in another article (Tommel et al., 2022, unpublished).

Last, participants in the intervention group were asked to complete evaluation questionnaires about their satisfaction and experiences with the eHealth care pathway. Other instruments used in this study have been described elsewhere (18).

Sample Size

The sample size calculation was based on the primary outcome measure, the continuous composite variable (PHQ-ADS) of the PHQ-9 and GAD-7 scales. Other trials that evaluated psychological interventions among chronic conditions with these scales showed Cohen d effect sizes from 0.28 to 0.63 (36–38). We considered Cohen d between the intervention and control groups of 0.46 on the PHQ-ADS composite to be feasible, with a power of 0.80 at the .05 significance level. Based on this effect size and considering a potential 15% dropout rate, we aimed to include 120 patients.

Randomization

Randomization to either the intervention or control group (1:1) was performed using random number tables with random block sizes of 4 and 6, created with an online number generator (random.org) and stratified by medical center and sex. Randomization tables were concealed from the main executive researcher, and cells containing randomization indicators were hidden until a participant was assigned. Each participant was allocated to a condition by an independent data manager, who revealed the relevant randomization indicator. Next, the data manager notified the researcher, who communicated allocation to the participant.

Blinding

Because of the nature of the intervention, participants, researchers, and therapists were not masked to the assigned group. General practitioners and internist-nephrologists were informed about the group. Participant identification codes were used to link data to participants. Study personnel and the data manager (who conducted data monitoring) were the only people with access to personalized data.

Statistical Methods

Baseline sample characteristics were computed for the intervention and control groups together and separately. Differences between complete cases and cases with missing data at any time point were examined using independent-samples t tests for continuous variables and χ2 tests for categorical variables. These initial data analyses showed that cases with missing data more often completed paper-and-pencil questionnaires than complete cases (39). Digitally, answers were required for most items leading to few missing data. We included covariate “paper” in the main analyses, indicating whether participants completed all self-report measures digitally or filled in questionnaires on paper at any time point.1

To describe the intervention effect in terms of (standardized) treatment outcome differences, mean change scores over time (by subtracting the baseline score from posttest and follow-up scores) were compared between the intervention and control groups. For personalized outcomes (PPPQ), patients reported their perceived progress at posttest and follow-up as a comparison to the previous time point, which precluded subtraction of baseline scores: Means at posttest and follow-up on the PPPQ were used as mean change scores over time. Furthermore, for all outcomes, Cohen d effect sizes were calculated.2 Effect sizes of 0.2, 0.5, and 0.8 were considered small, medium, and large, respectively (40).

To analyze intervention effectiveness, that is, the effect of the treatment condition (intervention or control) over time, we performed intention-to-treat analysis (including all 121 participants; Figure 3) combined with linear mixed-effects regression (i.e., longitudinal multilevel analysis) using the full-information maximum likelihood estimation method (39). To perform this analysis per outcome variable, we created one long format data set with the outcome scores at baseline, posttest, and follow-up below each other. We further created a time variable with values 0 (baseline), 1 (posttest = short-term), and 2 (follow-up = long-term). From this time variable, two dummy variables were created with baseline as reference category, reflecting the short-term (posttest versus baseline) and long-term (follow-up versus baseline) effect of time. Finally, we created the interaction terms between group (intervention = 1 and control = 0) and these dummy variables, to investigate the short-term and long-term effect of the intervention. The linear mixed-effects regression models included the following fixed effects: the two dummy variables of time, paper (a dichotomous variable indicating digital questionnaire completion versus any time point on paper), the interaction terms short-term by group and long-term by group, and the baseline covariates age and sex were included to adjust for potential influence. We assumed that the group means were equal at baseline (following the recommended strategy for longitudinal analysis in RCTs by Fitzmaurice and colleagues; (41)); therefore, the fixed effect of group was not included in the analysis. To improve model fit per outcome, the best variance-covariance matrix was selected (using restricted maximum likelihood), and the need for random intercept or slopes was tested with the likelihood ratio test for nested models and the lowest Akaike information criterion values for nonnested models (see SDC 3, Table S3, https://links.lww.com/PSYMED/A890, for an overview of final models). Assumptions for linear mixed-effects modeling (i.e., normally distributed random effects and error terms, no influencing outliers, and independent errors) were checked. We performed Holm-Bonferroni correction for multiple testing (42) on the 10 tests in total (i.e., two tests per primary and secondary outcome) to determine significance with an overall type 1 error rate of α = .05.

FIGURE 3:

Participant flow. PHQ-9 = Patient Health Questionnaire Depression Scale; GAD-7 = Generalized Anxiety Disorder scale.

To assess the intervention effectiveness for personalized secondary outcomes (PPPQ), one-way analyses of covariance (ANCOVAs) were conducted, with group as the independent variable; paper, age, and sex as covariates; and PPP-functioning and PPP-self-management at posttest and follow-up as dependent variables, respectively. To avoid loss of power and biased results of these analyses, missing data were imputed using multiple imputation (10 repetitions) under the “missing at random” assumption. Assumptions for ANCOVA analyses (i.e., normally distributed residuals, no influencing outliers, and homogeneity of regression slopes) were checked. Significance of the four ANCOVA analyses with our personalized outcomes was determined using the Holm-Bonferroni multiple test correction (42) with an overall α level of .05.

Because the primary outcome psychological distress is a composite measure, we exploratorily analyzed linear mixed-effects models with depressive and anxiety symptoms separately, to understand whether the intervention effectiveness differed for those separate outcomes. For these exploratory analyses, we did not focus on significance testing and therefore did not apply a multiple test correction. For all outcomes, sensitivity analyses were conducted to test the robustness of our results, including analyses without adjustments for baseline covariates, ANCOVA analyses without imputing missing data, and analyses in the per-protocol sample, which excluded intervention participants who dropped out of treatment.

Analyses were performed with SPSS version 27.0 (IBM). Linear mixed-effects models were performed with the MIXED procedure and ANCOVA models with the UNIANOVA procedure.

RESULTS Participant Flow

Between April 2018 and March 2020, 460 of 2240 (20.5%) eligible patients with CKD not receiving dialysis completed screening questionnaires. Screening results of 146 patients (31.7%) showed increased-risk profiles of at least mild depressive or anxiety symptoms and at least one suboptimal self-management behavior, of whom 121 (82.9%) were randomly assigned to the intervention (n = 60) or control group (n = 61). Eight patients dropped out during the trial, leaving 113 (93.4%) who completed the allocated group. Eleven adverse events occurred in the intervention group and 7 in the control group, which all required hospitalization. Adverse events were unrelated to study procedures, and no participant withdrawals occurred because of intervention harms. Figure 3 shows the participant flow.

Baseline Characteristics

Table 1 includes baseline characteristics of the randomized sample. Most participants were men, born in the Netherlands, and had a partner. The majority (59.5%) had never received psychological treatment in the past. Ages ranged from 25.8 to 81.6 years. The mean (standard deviation) estimated glomerular filtration rate was 49.6 (18.5) ml/min per 1.73 m2, and 65.3% were kidney transplant recipients. Mean office systolic and diastolic blood pressures were 138.6 (17.0) and 80.9 (9.0) mm Hg, respectively. The mean body mass index was 27.9 (5.4) kg/m2, and waist circumference was 100.0 (15.3) cm.

TABLE 1 - Baseline Participant Characteristics Characteristic Intervention (n = 60) Control (n = 61) Sociodemographic characteristics  Age, y 57.2 (12.6) 54.8 (15.0)  Male sex, n (%) 32 (53.3) 36 (59.0)  Country of birth, the Netherlands,  n (%) 54 (90.0) 55 (90.2)  Married/partnered, n (%) 44 (73.3) 45 (73.8)  Having children, n (%) 45 (75.0) 42 (68.9)  Low education a, n (%) 32 (53.3) 32 (52.5) b  Employed c, n (%) 27 (45.0) 34 (55.7) Disease and treatment characteristics  Primary cause of kidney failure, n (%)  Glomerulonephritis 7 (11.7) 15 (24.6)  Diabetes mellitus 13 (21.7) 4 (6.6)  Renal vascular disease 8 (13.3) 8 (13.1)  Cystic kidney diseases 7 (11.7) 7 (11.5)  Interstitial nephritis 8 (13.3) 3 (4.9)  Other cause 11 (18.3) d 21 (34.4) e  Kidney transplant recipient, n (%) 40 (66.7) 39 (63.9)  Time since last kidney transplantation f, y 6.8 [8.8] 6.9 [12.6]  History of dialysis, n (%) 22 (36.7) 29 (47.5) b  No. physical comorbidities for which  in treatment, n (%)  0 18 (30.0) 19 (31.1)  1 19 (31.7) 17 (27.9)  2 13 (21.7) 12 (19.7)  ≥3 10 (16.7) 13 (21.3)  Diabetes mellitus, n (%) 24 (40.0) 14 (23.0)  Cardiovascular disease g, n (%) 24 (40.0) 24 (39.3)  Hypertension, n (%) 44 (73.3) 53 (86.9)  Antihypertensive medication use,  n (%) 49 (81.7) 49 (80.3)  Treatment history psychological  complaints, n (%) 25 (41.7) 24 (39.3) Biochemical measures  Sodium excretion rate, mmol/24 h 150.1 (51.1) e 145.4 (58.8) h  Protein excretion rate, mmol/24 h 0.19 [3.80] h 0.15 [5.24] i  Urea excretion rate, mmol/24 h 392.0 [703.1] j 319.0 [571.5] i  Creatinine excretion rate, mmol/24 h 12.6 [27.2] e 11.3 [15.2] i  Albumin excretion rate, mmol/24 h 31.3 [3199.3] k 38.4 [4112.1] l  Potassium excretion rate, mmol/24 h 66.6 [132.0] h 64.0 [120.0] m  eGFR, ml/min per 1.73 m2 52.1 (18.7) 47.2 (18.1)  Hemoglobin, mmol/L 8.2 (0.9) n 8.3 (1.0) n  Total cholesterol, mmol/L 4.6 (1.0) e 4.5 (1.0) o  LDL cholesterol, mmol/L 2.4 [5.4] j 2.4 [1.1] j  HDL cholesterol, mmol/L 1.4 [0.6] e 1.3 [0.5] o Blood pressure and anthropometric  measures  Office SBP, mm Hg 140.5 (16.6) 136.8 (17.3) b  Office DBP, mm Hg 82.3 (8.1) 79.4 (9.6) b  Body mass index, kg/m2 27.3 [5.7] 26.5 [6.2]  Waist circumference, cm 101.0 [24.0] b 100.0 [20.5] o Self-management behaviors  Dietary adherence 1–10 score 6.6 (2.1) 6.4 (2.3)  Physical activity, h/wk 14.9 [17.1] 11.4 [15.8]  Nonsmoking 52 (86.7) 58 (95.1)  Medication adherence, 1–6 score 6.0 [1.0] 5.0 [2.0]  Alcohol consumption, units/wk 0.0 [4.8] 0.0 [3.0]  Depressive symptoms, 0–27 score 7.5 (3.2) 8.3 (3.4)  Anxiety symptoms, 0–21 score 5.5 (3.8) 5.5 (3.8)

eGFR = estimated glomerular filtration rate; LDL = low-density lipoprotein; HDL = high-density lipoprotein; SBP = systolic blood pressure; DBP = diastolic blood pressure.

Values for categorical variables are presented as count (proportion); values for continuous variables are given as mean (standard deviation) for normally distributed variables or median [interquartile range] for skewed variables.

a Low education includes primary, prevocational, and vocational education; high education includes advanced secondary and tertiary education.

b One unknown.

c Paid job, unpaid/voluntary work, or self-employed.

d Six unknown.

e Three unknown.

f Only for kidney transplant recipients.

g Cardiovascular disease was defined by the presence of coronary disease, angina pectoris, myocardial infarction, cerebrovascular accident, peripheral arterial disease, arrhythmia, or heart failure.

h Seven unknown.

i Eight unknown.

j Five unknown.

k Ten unknown.

l Twelve unknown.

m Eleven unknown.

n Two unknown.

o Four unknown.

Intervention Adherence, Module Use, and Evaluation

In the intervention group, 54 patients (90.0%) completed the iCBT treatment according to protocol. Reasons for noncompletion were not experiencing gain (n = 3), too high burden (n = 2), and health reasons (n = 1). Treatment dropouts had a significantly higher age (mean [standard deviation] = 67.9 [7.3]) than completers (56.0 [12.6]; p = .026), higher baseline diastolic blood pressure (83.4 [7.5] versus 72.1 [6.1]; p < .001), and more physical comorbidities (3.0 [1.3] versus 1.1 [1.1]; p < .001). With regard to baseline scores on outcomes, treatment dropouts had a significantly lower physical HRQoL (28.7 [7.0]) than completers (35.5 [7.6]; p = .041), and poorer disease self-management (73.8 [9.9] versus 81.5 [8.5]; p = .042). One participant dropped out of treatment immediately after the intake session, before starting online modules. The mean treatment duration of the other dropouts was 5.6 (4.7) weeks, and they used 1.4 (2.1) out of 14 modules on average. One treatment dropout did complete measurements at posttest and one at all time points.

The mean treatment duration (excluding planned weeks of inactivity) of completers was 15.0 (4.1) weeks (range, 8–29 weeks) and they used 5.7 (2.2) modules on average (range, 1–10). In addition to introduction module “your goals” and final module “your long-term goals,” the most frequently used module was “your lifestyle: goal exploration” (n = 43), followed by “your lifestyle: goals in action,” “your thoughts,” and “your relaxation exercises” (all n = 28). The least used modules were “your complaints: pain” (n = 3) and “your complaints: itch” (