Abstract
Background and objectives
Larger weight gain and higher ultrafiltration rates have been associated with poorer outcomes among patients on dialysis. Dietary restrictions reduce fluid-related risk; however, adherence is challenging. Alternative fluid mitigation strategies include treatment time extension, more frequent dialysis, adjunct peritoneal dialysis, and wearable ultrafiltration devices. No data regarding patient preferences for fluid management exist. A survey was designed, tested, and administered to assess patient-stated preferences regarding fluid mitigation.
Design, setting, participants, & measurements
A written survey concerning fluid-related symptoms, patient and treatment characteristics, and fluid management preferences was developed. The cross-sectional survey was completed by 600 patients on hemodialysis at 18 geographically diverse ambulatory facilities. Comparisons of patient willingness to engage in volume mitigation strategies across fluid symptom burden, dietary restriction experience, and patient characteristics were performed.
Results
Final analyses included 588 surveys. Overall, if allowed to liberalize fluid intake, 44.6% of patients were willing to extend treatment time by 15 minutes. Willingness to extend treatment time was incrementally less for longer treatment extensions; 12.2% of patients were willing to add a fourth weekly treatment session, and 13.5% of patients were willing to participate in nocturnal dialysis three nights per week. Patients more bothered by their fluid restrictions (versus less bothered) were more willing to engage in fluid mitigation strategies. Demographic characteristics and symptoms, such as cramping and dyspnea, were not consistently associated with willingness to engage in the proposed strategies. More than 25% of patients were unsure of their dry weights and typical interdialytic weight gains.
Conclusions
Patients were generally averse to treatment time extension>15 minutes. Patients more bothered (versus less bothered) by their prescribed fluid restrictions were more willing to engage in volume mitigation strategies. Additional study of patient-stated preferences in hemodialysis treatment practices is needed to guide patient care and identify deficiencies in patient treatment and disease-related knowledge.
Keywords: hemodialysis, ultrafiltration, ESRD
Introduction
Patients on hemodialysis (HD) have mortality rates>6-fold the rates of the general population (1). An expanding evidence base suggests that volume-related metrics, including greater interdialytic weight gain (IDWG) and more rapid fluid removal during HD, may contribute to poor outcomes (2–6).
Higher IDWG necessitates more rapid ultrafiltration (UF) rates during dialysis, and inadequate fluid removal results in chronic volume expansion. Higher IDWG and UF rates have been linked to greater morbidity and mortality (2–6). Currently, fluid and salt restrictions are the principle means used to minimize IDWG and thereby, rapid UF rates, but research and clinical experience show that adherence to these otherwise physiologically sound interventions is difficult (7,8). As a result, as many as 25%–50% of patients on HD are chronically volume-expanded, and many patients are routinely exposed to high UF rates (9). To mitigate risk from hypervolemia and fluid removal practices, novel approaches to fluid management are needed. Potential strategies to reduce IDWG include additional weekly HD sessions to shorten the inter-HD interval as well as the time for fluid accumulation, adjuvant peritoneal dialysis (PD), and interdialytic UF through wearable devices. Strategies to obviate the need for more rapid UF rates include IDWG reduction and treatment time (TT) extension.
Patient willingness to adopt potential interventions is a necessary prerequisite for treatment success. Selecting therapies that align with patient preferences engenders greater potential for adherence and, thus, greater potential for realization of any derivative therapeutic benefit. To date, there has been no broad assessment of patient-stated preferences regarding potential novel therapies for fluid management. We developed and tested a fluid management written survey instrument and administered the survey to 600 chronic ambulatory HD patients to assess patient willingness to extend TT, add a fourth weekly HD session, perform nocturnal HD three times per week, adopt adjunct PD, and use wearable UF devices as IDWG and UF rate mitigation strategies in lieu of dietary restrictions. We sought to determine if patient characteristics, such as HD treatment properties, fluid symptom burden, experience with dietary restrictions, and demographic features, were associated with patient-stated preferences in fluid management strategies. We hypothesized that patients with larger IDWG and greater fluid-related symptom burdens would be more willing to adopt the proposed fluid mitigation strategies.
Materials and Methods
Overview
The written survey instrument was developed in three steps: (1) domain and item identification through literature review and patient input, (2) item selection through the development of a preliminary questionnaire with survey research and dialysis professional reviews, and (3) pretesting through patient comprehension testing and a field pilot administration test (Supplemental Figure 1). The final written survey instrument was administered to patients during a routine ambulatory HD session at 18 Dialysis Clinic Incorporated (DCI) dialysis facilities between September and November of 2013. Survey instrument development phases and final survey administration were approved by the Partners HealthCare Institutional Review Board.
Survey Development: Domain and Item Identification and Item Selection
MEDLINE searches to identify symptom burden scales validated in patients on HD and volume-related items validated in patients with heart failure and kidney disease were conducted (Supplemental Table 1). A small group discussion was held with three volunteer patients on HD to elucidate patient experiences with HD and fluid overload, as well as patient knowledge about different volume mitigation strategies.
A written survey instrument designed for self-administration in <20 minutes was developed. Five domains (volume overload symptom burden, fluid management strategy preferences, HD treatment characteristics, physical function, and demographics) were selected for inclusion. Individual items were taken from existing validated scales and questionnaires when possible, and additional items were generated to reflect themes not encompassed by existing surveys. HD treatment and demographic variables were selected to capture characteristics that might influence volume management preferences. Volume mitigation strategies were selected to reflect both presently available treatment options and experimental strategies. The draft instrument was reviewed by three survey research professionals and three dialysis experts to assess scales, content validity, and interpretability.
Survey Development: Pretesting
Patient survey comprehension testing was then conducted through a convenience sample of 10 patients on chronic HD who were acutely hospitalized at Brigham and Women’s Hospital in Boston, Massachusetts. Patients identified unclear items and commented on survey length; the instrument was modified to incorporate feedback. Field pilot testing of the modified instrument was performed in 50 patients on HD during a routine outpatient HD session and repeated 2 weeks later in 48 of the 50 patients. Pilot study results were analyzed for item response distribution and frequency, construct validity, reliability, and test–retest reliability. The instrument was modified on the basis of patient feedback and psychometric results. (Supplemental Table 2 displays characteristics of patients participating in instrument pretesting.)
Survey Administration and Data Collection
The final survey instrument was distributed to patients at 18 DCI outpatient dialysis units. Patients on in-center HD aged≥18 years old who were able to read and complete an English language written survey without assistance were eligible. Exclusion criteria included patients on PD and home HD. HD treatment and demographic data were self-reported; facility staff did not assist with survey completion. Written survey completion represented implied consent to participate in research; patients received no remuneration. In total, 1163 surveys were mailed to HD units, and 600 surveys were returned. Surveys with <50% question responses (n=5) or missing age (n=3) or sex (n=4) were excluded, leaving 588 surveys for analysis.
Statistical Analyses
Pilot survey results were evaluated for response category frequency and distribution by counts and histograms. Psychometric analyses included assessment of reliability, construct validity, and test–retest reliability. Cronbach α (a threshold of 0.70 is regarded as good reliability among test items) was used to assess internal consistency and reliability within constructs. Test–retest reliability was assessed with the κ-statistic (proportion of chance-corrected agreement or a measure of agreement) (10) between responses to the volume mitigation strategy willingness questions from the two pilot survey administrations.
Unit response rates were calculated by dividing the number of returned surveys by the number of mailed surveys on a facility-to-facility basis. Mailed survey numbers were on the basis of rough estimates of eligible patients by clinic administrators and medical directors. Data regarding the actual number of patients approached who declined to complete surveys are not available. Reported response rates are likely underestimations, because most units reported receiving more surveys than they had eligible patients.
Demographic and HD treatment data were reported as counts and proportions for categorical variables and means and SDs for continuous variables. Bivariable comparisons across categories of fluid restriction burden, residual urine output, lower extremity swelling, IDWG, dyspnea, and HD-associated cramping were made using chi-squared tests. All analyses were performed using STATA 12.1MP (College Station, TX).
Results
Survey Instrument Pilot and Psychometric Testing
The survey pilot test was completed by 50 patients on HD (76% participation rate) during a routinely scheduled ambulatory HD session at a Boston, Massachusetts, dialysis clinic; 48 patients completed retesting 2 weeks later. The median survey completion time was 16 minutes (range=10–28 minutes). No individual item response was omitted by more than two patients. Response category counts and histograms revealed adequate distribution and frequency across response categories for all multiple choice questions. Dry weight, TT, and IDWG free response questions had high completion rates (88%–96%).
Psychometric testing revealed high internal consistency across four tested constructs: fluid-related symptom severity (Cronbach α=0.72) and mild (Cronbach α=0.83), moderate (Cronbach α=0.88), and severe physical limitation (Cronbach α=0.91). Test–retest reliability of responses to willingness to participate in UF mitigation strategies across two survey administrations (2-week span) was strong, with κ-coefficients ranging from 0.53 to 0.88 (Supplemental Table 3). The final survey instrument is available in the Supplemental Material.
Surveyed Patient Characteristics
The mean survey response rate was 55.6%±30.2% and ranged from 0% to 98.3% (median=60.4%) across centers. Excluding the center with zero of 100 responses, the mean response rate was 67.9%±21.6%. The participating dialysis units represented diverse geographic regions across the United States (Table 1) and included academic center– and community-based units as well as rural and urban units. Respondent demographic and HD treatment characteristics are displayed in Tables 2 and 3. Overall, respondents were similar to the broader United States HD population in terms of age and sex (1). Black patients were over-represented as 47.6% of respondents. The mean IDWG was 2.8±1.1 kg, and the mean TT was 229.7±45.6 minutes; 2.8% of patients dialyzed nocturnally. Prescribed fluid restrictions were reported by 74.2% of patients. Of 436 patients on fluid restrictions, 42.7% reported adherence to their restriction <1 day per week. Of surveyed patients, 30.6% of patients were unsure of their dry weights, 26.2% of patients were unsure of typical IDWGs, and 5.9% of patients were unsure of TTs.
Table 1.
Geographic locations of survey respondents
| Location | n |
|---|---|
| Northeast | |
| Maine (1) | 13 |
| Massachusetts (2) | 58 |
| New York (1) | 53 |
| Pennsylvania (2) | 65 |
| Midwest | |
| Indiana (1) | 91 |
| Missouri (2) | 23 |
| Southeast | |
| Alabama (3) | 70 |
| Florida (3) | 110 |
| West | |
| Montana (1) | 63 |
| New Mexico (2) | 54 |
| Total patients | 600 |
State are listed with the number of participating units in parentheses.
Table 2.
Demographic characteristics of surveyed patients by volume-related risk mitigation strategy willingness
| Characteristic | Total (n=588) | (+) ↑ TT by 15 min (n=262) | (−) ↑ TT by 15 min (n=321) | (+) Add Fourth Weekly HD (n=72) | (−) Add Fourth Weekly HD (n=509) |
|---|---|---|---|---|---|
| Age (yr) | |||||
| ≤39 | 60 (10.2%) | 27 (10.3%) | 32 (10.0%) | 11 (15.3%) | 48 (9.4%) |
| 40–59 | 235 (40.0%) | 99 (37.8%) | 136 (42.3%) | 32 (44.4%) | 201 (39.5%) |
| 60–69 | 135 (23.0%) | 66 (25.2%) | 68 (21.2%) | 13 (18.1%) | 121 (23.8%) |
| ≥70 | 158 (26.8%) | 70 (26.7%) | 85 (26.5%) | 16 (22.2%) | 139 (27.3%) |
| Sex | |||||
| Men | 339 (57.6%) | 143 (54.6%) | 194 (60.4%) | 37 (51.4%) | 299 (58.7%) |
| Women | 249 (42.4%) | 119 (45.4%) | 127 (39.6%) | 35 (48.6%) | 210 (41.3%) |
| Race | |||||
| White | 202 (34.3%) | 98 (37.4%) | 103 (32.1%) | 20 (27.8%) | 180 (35.3%) |
| Black | 280 (47.6%) | 125 (47.7%) | 154 (48.0%) | 43 (59.7%) | 236 (46.4%) |
| Othera | 105 (17.9%) | 39 (14.9%) | 63 (19.6%) | 9 (12.5%) | 92 (18.1%) |
| Missing | 1 (0.2%) | 0 | 1 (0.3%) | 0 | 1 (0.2%) |
| Education | |||||
| No HS graduation | 105 (17.8%) | 48 (18.3%) | 54 (16.8%) | 17 (23.6%) | 85 (16.7%) |
| HS graduate/GED | 227 (38.6%) | 92 (35.1%) | 133 (41.4%) | 27 (37.5%) | 198 (38.9%) |
| Some college or more | 255 (43.4%) | 122 (46.6%) | 133 (41.4%) | 27 (37.5%) | 226 (44.4%) |
| Missing | 1 (0.2%) | 0 | 1 (0.3%) | 1 (1.4%) | 0 |
| Employment statusb | |||||
| Collecting disability | 202 (34.4%) | 82 (31.3%) | 118 (36.8%) | 27 (37.5%) | 172 (33.8%) |
| Retired, homemaker | 289 (49.1%) | 139 (53.1%) | 147 (45.8%) | 36 (50.0%) | 249 (48.9%) |
| Unemployed, looking | 25 (4.2%) | 11 (4.2%) | 14 (4.4%) | 1 (1.4%) | 24 (4.7%) |
| Part-time work | 36 (6.1%) | 14 (5.3%) | 22 (6.8%) | 2 (2.8%) | 34 (6.7%) |
| Full-time work | 35 (6.0%) | 15 (5.7%) | 20 (6.2%) | 6 (8.3%) | 29 (5.7%) |
| Missing | 1 (0.2%) | 1 (0.4%) | 0 | 0 | 1 (0.2%) |
| Heart failure | |||||
| Yes | 219 (37.2%) | 93 (35.5%) | 125 (38.9%) | 22 (30.6%) | 196 (38.5%) |
| No | 365 (62.1%) | 168 (64.1%) | 194 (60.5%) | 50 (69.4%) | 310 (60.9%) |
| Missing | 4 (0.7%) | 1 (0.4%) | 2 (0.6%) | 0 | 3 (0.6%) |
| Location | |||||
| Northeast | 186 (31.6%) | 83 (31.7%) | 102 (31.8%) | 22 (30.5%) | 163 (32.0%) |
| Southeast | 172 (29.3%) | 74 (28.2%) | 96 (29.9%) | 11 (15.3%) | 158 (31.0%) |
| Midwest | 114 (19.4%) | 52 (19.9%) | 62 (19.3%) | 26 (36.1%) | 88 (17.3%) |
| West | 116 (19.7%) | 53 (20.2%) | 61 (19.0%) | 13 (18.1%) | 100 (19.7%) |
All characteristics (with the exception of geographic region) were patient reported. Five patients omitted the 15-minute increase question, and seven patients omitted the fourth weekly session question; these patients were excluded from table comparisons. HS, high school; GED, general equivalency diploma; TT, treatment time; HD, hemodialysis.
Includes American Indian, Alaskan, Hawaiian, Pacific Islander, and Hispanic/Latino.
Selection of more than one response category was allowed.
Table 3.
Self-reported dialysis characteristics of surveyed patients by volume-related risk mitigation strategy willingness
| Characteristic | Total (n=588) | (+) ↑ TT by 15 min (n=262) | (−) ↑ TT by 15 min (n=321) | (+) Add Fourth Weekly HD (n=72) | (−) Add Fourth Weekly HD (n=509) |
|---|---|---|---|---|---|
| Dry weight (quartiles; kg) | |||||
| ≤67 | 112 (19.1%) | 51 (19.5%) | 60 (18.7%) | 13 (18.0%) | 98 (19.3%) |
| 68–80 | 93 (15.8%) | 43 (16.4%) | 49 (15.3%) | 11 (15.3%) | 81 (15.9%) |
| 81–97 | 100 (17.0%) | 45 (17.2%) | 55 (17.1%) | 16 (22.2%) | 84 (16.5%) |
| ≥98 | 96 (16.3%) | 47 (17.9%) | 48 (14.9%) | 12 (16.7%) | 82 (16.1%) |
| Not sure | 180 (30.6%) | 73 (27.9%) | 105 (32.7%) | 20 (27.8%) | 157 (30.8%) |
| Missing | 7 (1.2%) | 3 (1.1%) | 4 (1.3%) | 0 | 7 (1.4%) |
| IDWG (tertiles; kg) | |||||
| ≤2 | 165 (28.1%) | 55 (21.0%) | 107 (33.3%) | 18 (25.0%) | 143 (28.1%) |
| 2.1–3 | 159 (27.0%) | 86 (32.8%) | 73 (22.8%) | 26 (36.1%) | 133 (26.1%) |
| ≥3.1 | 104 (17.7%) | 53 (20.2%) | 51 (15.9%) | 19 (26.4%) | 84 (16.5%) |
| Not sure | 154 (26.2%) | 65 (24.8%) | 87 (27.1%) | 9 (12.5%) | 143 (28.1%) |
| Missing | 6 (1.0%) | 3 (1.2%) | 3 (0.9%) | 0 | 6 (1.2%) |
| TT (min) | |||||
| ≤239 | 255 (43.4%) | 106 (40.5%) | 145 (45.2%) | 29 (40.3%) | 221 (43.4%) |
| ≥240 | 298 (50.7%) | 141 (53.8%) | 157 (48.9%) | 39 (54.2%) | 258 (50.7%) |
| Not sure | 35 (5.9%) | 15 (5.7%) | 19 (5.9%) | 4 (5.6%) | 30 (5.9%) |
| Prescribed a fluid restriction | |||||
| Yes | 436 (74.2%) | 209 (79.8%) | 224 (69.8%) | 55 (76.4%) | 376 (73.9%) |
| No | 150 (25.5%) | 53 (20.2%) | 96 (29.9%) | 17 (23.6%) | 132 (25.9%) |
| Missing | 2 (0.3%) | 0 | 1 (0.3%) | 0 | 1 (0.2%) |
| Fluid restriction amount (L) | |||||
| ≤1 | 299 (68.6%) | 138 (66.0%) | 160 (71.4%) | 41 (74.5%) | 256 (68.1%) |
| 1.1–1.9 | 38 (8.7%) | 25 (12.0%) | 12 (5.4%) | 4 (7.3%) | 32 (8.5%) |
| ≥2 | 43 (9.9%) | 21 (10.0%) | 22 (9.8%) | 6 (10.9%) | 37 (9.8%) |
| Missing | 56 (12.8%) | 25 (12.0%) | 30 (13.4%) | 4 (7.3%) | 51 (13.6%) |
| Frequency of meeting fluid restriction | |||||
| Less than one time per week | 186 (42.7%) | 79 (37.8%) | 106 (47.3%) | 25 (45.4%) | 159 (42.3%) |
| One to three times per week | 151 (34.6%) | 74 (35.4%) | 75 (33.5%) | 19 (34.6%) | 129 (34.3%) |
| Daily | 89 (20.4%) | 51 (24.4%) | 38 (17.0%) | 10 (18.2%) | 79 (21.0%) |
| Missing | 10 (2.3%) | 5 (2.4%) | 5 (2.2%) | 1 (1.8%) | 9 (2.4%) |
| Vintage (yr) | |||||
| ≤0.9 | 155 (26.3%) | 61 (23.3%) | 93 (29.0%) | 17 (23.6%) | 137 (26.9%) |
| 1–5 | 272 (46.3%) | 127 (48.5%) | 142 (44.2%) | 25 (34.7%) | 242 (47.5%) |
| ≥5.1 | 153 (26.0%) | 71 (27.1%) | 81 (25.2%) | 29 (40.3%) | 123 (24.2%) |
| Missing | 8 (1.4%) | 3 (1.1%) | 5 (1.6%) | 1 (1.4%) | 7 (1.4%) |
| Residual urine output | |||||
| None | 129 (21.9%) | 63 (24.0%) | 66 (20.6%) | 21 (29.2%) | 108 (21.2%) |
| A little | 175 (29.8%) | 87 (33.2%) | 88 (27.4%) | 23 (31.9%) | 151 (29.6%) |
| Some | 206 (35.0%) | 87 (33.2%) | 115 (35.8%) | 22 (30.6%) | 179 (35.2%) |
| A lot | 73 (12.4%) | 23 (8.8%) | 50 (15.6%) | 6 (8.3%) | 67 (13.2%) |
| Missing | 5 (0.9%) | 2 (0.8%) | 2 (0.6%) | 0 | 4 (0.8%) |
All dialysis characteristics were patient reported. Five patients omitted the 15-minute increase question, and seven patients omitted the fourth weekly session question; these patients were excluded from table comparisons. IDWG, interdialytic weight gain.
Willingness to Participate in Different Volume Mitigation Strategies
When patients were asked if they would participate in different volume mitigation strategies “if it meant that you could drink as much as you want,” 44.6% of patients reported willingness to extend TT by 15 minutes, 21.3% of patients reported willingness to extend TT by 30 minutes, and 9.7% of patients reported willingness to extend TT by 45 minutes; 12.2% of patients were willing to add a fourth weekly HD session, 13.5% of patients were willing to participate in nocturnal 8-hour HD three nights per week, 10.2% of patients were willing to perform PD on non-HD days, and 19.9% of patients were willing to use a wearable UF device on non-HD days.
Patients who reported being moderately, very much, or extremely bothered by their prescribed fluid restriction (versus not at all or somewhat bothered) were more likely to be willing to increase TT by 15, 30, and 45 minutes, add a fourth weekly HD session, and use a wearable UF device (all P values <0.001) (Figure 1). There was a dose–response relationship between the degree to which patients were bothered by their fluid restriction and willingness to participate in volume mitigation strategies (Table 4). Willingness to participate in different volume mitigation strategies did not differ significantly by the prescribed fluid restriction amount or self-reported adherence to a prescribed fluid restriction (Supplemental Table 4).
Figure 1.
Fluid restriction bother defined as moderately, very much, or extremely bothered by their prescribed fluid restriction (versus not at all or somewhat bothered). P values reflect bivariable comparisons across two categories of fluid restriction burden. HD, hemodialysis; TT, treatment time; UF, ultrafiltration. aPatients on active nocturnal dialysis (n=12) were excluded from analysis.
Table 4.
Willingness to participate in volume mitigation strategies by incrementally greater perceived fluid restriction bother
| Strategy | Not Bothered (n=270) | Somewhat Bothered (n=129) | Moderately Bothered (n=96) | Very Much or Extremely Bothered (n=89) | P for Trenda |
|---|---|---|---|---|---|
| Increase TT by 15 min | 89 (33.2%) | 61 (48.0%) | 53 (55.2%) | 57 (64.0%) | <0.001 |
| Increase TT by 30 min | 37 (13.8%) | 24 (18.9%) | 27 (28.1%) | 35 (39.3%) | <0.001 |
| Increase TT by 45 min | 20 (7.5%) | 6 (4.7%) | 13 (13.5%) | 18 (20.2%) | 0.002 |
| Add fourth HD per week | 24 (9.0%) | 12 (9.5%) | 16 (16.8%) | 20 (22.5%) | 0.001 |
| Nocturnal HD three times per weekb | 29 (11.0%) | 22 (17.6%) | 12 (12.8%) | 14 (16.7%) | 0.16 |
| PD on non-HD days | 29 (10.3%) | 14 (11.5%) | 8 (8.9%) | 11 (12.4%) | 0.77 |
| Wearable UF device | 37 (14.1%) | 26 (21.3%) | 23 (25.3%) | 31 (35.2%) | <0.001 |
Five patients omitted the 15- and 30-minute increase questions, and seven patients omitted the fourth weekly session question; these patients were excluded from table comparisons. PD, peritoneal dialysis; UF, ultrafiltration.
Nonparametric test for trend across ordered groups by an extension of Wilcoxon rank sum testing.
Active nocturnal dialysis patients (n=12) were excluded from analysis.
We hypothesized that patients more bothered by fluid-related symptoms or with higher IDWG would be more willing to participate in different volume mitigation strategies, but results were mixed. Shortness of breath at rest, dyspnea-related activity limitation, cramping, and peridialytic dizziness were not significantly associated with willingness to participate in the proposed volume mitigation strategies. Patients bothered by lower extremity swelling (moderately, very much, or extremely bothered versus not at all or somewhat bothered) were more likely to be willing to increase TT by 30 minutes (29.7% versus 19.7%; P=0.03) and use a wearable UF device on non-HD days (28.3% versus 19.1%; P=0.04), but associations with other strategies were nonsignificant. Patients with higher weight gain (≥3 versus ≤2.9 kg) were more likely to be willing to increase TT by 30 minutes (33.7% versus 19.3%; P=0.002), use non-HD day PD (19.6% versus 9.2%; P=0.005), and use a wearable UF device (32.7% versus 21.3%; P=0.02); associations between IDWG and other volume mitigation strategies were nonsignificant. Patients with none or a little residual urine output (versus some or a lot of urine output) were more likely to be willing to increase TT by 15 (49.3% versus 40.0%; P=0.02) or 30 minutes (26.3% versus 16.4%; P=0.004) and use a wearable UF device (25.4% versus 15.7%; P=0.004) (Supplemental Table 4).
Finally, patients who reported being moderately, very much, or extremely bothered by fatigue after dialysis (versus not at all or somewhat bothered) were more likely to be willing to try nocturnal HD three times per week (18.3% versus 11.0%; P=0.01); associations between fatigue and other strategies were nonsignificant.
Discussion
Patients on HD experience significant morbidity and mortality from volume overload and rapid fluid removal; however, no data regarding patient-stated preferences for treatment approaches to fluid management exist. Our survey revealed that, if patients were allowed to drink as much fluid as they desired, >40% would be willing to extend their TT by 15 minutes, but willingness to extend TT decreased incrementally with greater TT extension. Patients who were more bothered by fluid restrictions were more likely to be willing to engage in different volume/UF mitigation strategies. Demographic characteristics and symptoms, such as cramping, dizziness, and dyspnea, were not consistently associated with willingness to engage in the volume/UF mitigation strategies. Finally, our results revealed that >25% of patients were unsure of their dry weights and typical IDWGs, and >40% of patients adhered to their prescribed daily fluid restrictions <1 day per week.
Dietary restrictions are the cornerstone of volume management; however, adherence to either salt or fluid restriction is difficult, and adherence to both, a necessity for successful volume reduction, is even more challenging (7,8). In a small focus group–based study on fluid management, Smith et al. (11) identified inadequate knowledge and lack of motivation as the primary barriers to fluid restriction adherence; the study did not explore perceptions of nondietary-based interventions. Similar roadblocks to dietary restrictions are present among patients with heart failure (12,13). Despite the challenges associated with dietary restrictions, improved adherence has been shown with targeted educational programs, cognitive behavioral therapy, and dietary self-efficacy (14–16).
Although dietary restriction remains a viable volume mitigation strategy with intensive patient support and education, it is imperative that we develop alternative interventions. This need is underscored by our finding that >40% of patients self-reported daily fluid restriction adherence <1 day per week. To mitigate IDWG-related harm, non-HD day therapies, such as adjunct PD and wearable UF devices, may be beneficial. PD in patients with refractory heart failure has been shown to decrease hospitalizations and improve functional status (17). In a 13-patient study of 4-weeks duration, Jones et al. (18) showed lower pre-HD BP and IDWG among patients treated with near daily UF (4 days of UF and 2 days of UF and HD). Wearable UF and artificial kidney devices could provide a similar benefit (19) and have recently been approved for randomized study. Such strategies offer the promise of both IDWG and UF rate reduction. UF rate reduction (without IDWG reduction) can be achieved by TT extension. Historically, TT has been a relatively fixed prescription parameter, primarily determined by urea clearance metrics. However, session-to-session TT titration in response to observed IDWG is a potential strategy to reduce UF rates. Such a strategy would not only cap UF rates but might also deter IDWG as patients curb fluid intake to avoid longer TTs.
Our finding that fluid restriction bother was most strongly associated with willingness to participate in different volume/UF rate mitigation strategies is not surprising. Fluid restriction, particularly in the presence of reduced cardiac output, leads to increased neurohormonal system activation and hypothalamic thirst stimulation (20). Patients on HD may be particularly vulnerable to such triggers because of thirst augmentation from wide serum–dialysate sodium gradients (21). In fact, increased thirst among patients on HD is associated with increased IDWG and reduced quality of life (22).
Interestingly, symptoms that might improve with UF rate reduction (e.g., cramping and dizziness) or IDWG reduction (e.g., dyspnea and edema) were not consistently associated with willingness to participate in the mitigation strategies. Such incongruity suggests inadequate patient understanding of HD-related symptom physiology. Although our survey did not directly assess health literacy and HD-related knowledge, our results revealed that 30.6% of patients did not know their dry weights, 26.2% of patients did not know their typical IDWGs, and 5.9% of patients did not know their TTs. These findings expose important knowledge gaps and highlight the need for educational programs focused on disease-specific health literacy and motivational programs designed to engage patients in treatment plans.
Additionally, we found that >40% of patients would be willing to extend TT by 15 minutes if they could increase fluid intake; however, this willingness fell to <10% with 45 minutes of TT extension. Such resistance to TT extension is consistent with clinical experience. However, we were surprised that more patients were willing to add an extra weekly HD session than were willing to extend sessions by 45 minutes three times per week, suggesting that longer HD duration carries greater aversion than greater HD frequency (despite the greater cumulative TT associated with the latter). In contrast, more patients were willing to try 8-hour nocturnal dialysis than extend sessions by 45 minutes. This finding could be attributed to increased patient awareness of associations between nocturnal dialysis and improved quality of life (23) and is supported by our finding that patients more bothered by fatigue were more likely to be willing to participate in nocturnal HD.
Finally, our results revealed general aversion to adoption of most of the proposed fluid mitigation strategies. Such findings underscore the need for research focused on identifying alternative strategies for fluid management and the need for consideration of patient opinion in such research. Incorporation of patient opinion in the early stages of research may provide important data regarding potential for trial enrollment success and more importantly, the likelihood of ultimate therapeutic adoption.
To our knowledge, this study is the first effort to broadly assess patient preferences regarding fluid management. Its strengths include a large, geographically diverse sample size with demographic and treatment characteristics similar to the broader United States HD population and the use of a survey instrument developed with patient input and attention to patient-reported outcome standards (24).
Our study does have important limitations. First, convenience samples for instrument development were used, and participants may not have been representative of the broader HD population. Second, unit survey response rates varied widely; nonresponse bias may have affected results. Although it is reassuring that survey responders were similar to the broader United States HD population in terms of age, sex, TT, IDWG, and dialytic vintage, survey responders may have been differentially likely to engage in or may have differential experience with various volume mitigation strategies. Response rates might have been improved by allowing dialysis facility staff to aid in survey completion; however, it would have impaired our assessment of patient treatment knowledge. Third, HD and demographic data were self-reported; incorrect reporting may have introduced misclassification bias. Fourth, black patients were disproportionately represented in our survey responders; however, responses to strategy questions did not differ significantly between black and nonblack respondents. Additionally, we excluded patients on HD and home therapy and patients unable to complete a written English language survey; our results cannot be extrapolated to these populations. Also, the κ-statistic for test–retest reliability of the willingness to engage in PD item in instrument pilot testing was low and may suggest that patients had poor understanding of this question; PD-willingness question results should be interpreted with caution. Fifth, survey fluid mitigation strategies were selected parsimoniously to minimize respondent burden. Additional fluid mitigation strategies exist (e.g., diuretics), and patient preferences for other therapies should be examined.
In summary, this study showed that, even in the setting of relaxed fluid restrictions, patients were generally averse to TT extension by >15 minutes. Patients more bothered (versus less bothered) by their prescribed fluid restrictions were more willing to engage in volume mitigation strategies. Additionally, many patients did not know their dry weights and typical IDWGs. Finally, volume-related and UF rate–related symptoms did not correlate with willingness to participate in different volume mitigation strategies, suggesting a need for greater patient education. Additional study of patient-stated preferences in HD treatment practices is needed to guide patient care, identify educational opportunities, and inform future research.
Disclosures
J.E.F. has received speaking honoraria from Dialysis Clinic Incorporated. T.W.M. is an employee of John Snow, Inc., a public health management consulting and research organization. S.M.B. is an employee of DaVita Clinical Research, has received speaking honoraria from Fresenius Medical Care North America, and served on advisory boards for Amgen, C. B. Fleet, Keryx, and Otsuka; his spouse is employed by AstraZeneca. G.C.C. has served as a consultant to Allena Pharmaceuticals, AstraZeneca, and Exponent, is an author and section editor for UpToDate and the Editor-in-Chief of CJASN.
Supplementary Material
Acknowledgments
We thank Dialysis Clinic Incorporated (DCI), its clinical research director Karen Majchrzak, and its participating medical directors and dialysis unit staff for facilitating survey administration. We thank Fresenius Medical Care North America for facilitating focus group conduction. We also thank the research assistants at John Snow, Inc. for assistance with survey formatting and scanning. Finally, we thank the dialysis patients for taking part in all phases of this study.
This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health Grant DK093159-02 (to J.E.F.) and National Institutes of Health Grant 1KL2-TR001100-01 (to J.E.F.), a KL2 Medical Research Investigator Training award (an appointed KL2 award) from Harvard Catalyst/The Harvard Clinical and Translational Science Center National Center for Research Resources and the National Center for Advancing Translational Sciences. This work was also supported by National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health Grant DK91417 (to G.C.C.).
Neither DCI nor Fresenius Medical Care North America had any role in the design or analysis of this study. The content is solely the responsibility of the authors and does not necessarily represent the official views of Harvard Catalyst, Harvard University, and its affiliated academic health care centers or the National Institutes of Health.
Footnotes
Published online ahead of print. Publication date available at www.cjasn.org.
This article contains supplemental material online at http://cjasn.asnjournals.org/lookup/suppl/doi:10.2215/CJN.03280314/-/DCSupplemental.
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