Association of physical function with predialysis blood pressure in patients on hemodialysis

Mobility in Older Adults Receiving Maintenance Hemodialysis: A Qualitative Study

RATIONALE & OBJECTIVE

For older adults, maintaining mobility is a major priority, especially for those with advanced chronic diseases like kidney failure. However, our understanding of the factors affecting mobility in older adults receiving maintenance hemodialysis is limited.

STUDY DESIGN

Descriptive qualitative study.

SETTING & PARTICIPANTS

Using purposive sampling, we recruited (1) persons aged≥60 years receiving maintenance hemodialysis; and (2) care partners (≥18 years) providing regular support to an older adult receiving hemodialysis. During a single in-person home visit, we assessed mobility using the Short Physical Performance Battery (SPPB) and conducted individual one-on-one interviews regarding important personal factors related to mobility.

ANALYTICAL APPROACH

Descriptive statistics were used for demographic and SPPB data. Transcripts underwent thematic coding, informed by the International Classification of Function framework of mobility. We used conceptual content analysis to inductively extract themes and subthemes.

RESULTS

We enrolled 31 older adults receiving hemodialysis (42% female, 68% Black) with a mean age of 73±8 years and mean dialysis vintage of 4.6±3.5 years; their mean SPPB score was 3.6±2.8 points. Among 12 care partners (75% female, 33% Black), the mean age was 54±16 years and mean SPPB score was 10.1±2.4 points. Major themes extracted were (1) mobility represents independence; (2) mobility is precarious; (3) limitations in mobility cause distress; (4) sources of encouragement and motivation are critical; and (5) adaptability is key.

LIMITATIONS

Modest sample from single geographic area.

CONCLUSIONS

For older adults receiving hemodialysis, mobility is severely limited and is often precarious in nature, causing distress. Older adults receiving hemodialysis and their care partners have identified sources of encouragement and motivation for mobility, and cite an adaptable mindset as important. Future studies should conceptualize mobility as a variable condition and build on this outlook of adaptability in the development of interventions.

Association of Phase Angle, but Not Inflammation and Overhydration, With Physical Function in Peritoneal Dialysis Patients

Introduction: Muscle mass depletion, overhydration, and inflammatory state have been related to impaired physical function in chronic kidney disease patients. The relationship between bioelectrical impedance analysis (BIA) parameters, such as hydration status and phase angle (PhA), with physical function in peritoneal dialysis (PD), is still not well-established. Therefore, the objective was to evaluate the association of BIA parameters (overhydration index and PhA) and inflammatory markers with physical function in patients on PD.

Methods: The present cross-sectional study enrolled PD patients. Multifrequency BIA was performed to obtain overhydration index and PhA. The Short Physical Performance Battery (SPPB) test battery was applied to assess physical function. The time to complete the 4-m gait test and sit-to-stand test was also considered for physical function assessment. The inflammatory markers tumor necrosis factor-alpha and C-reactive protein levels were determined. Multiple linear regression models were performed, with the physical function variables as dependent variables, adjusted for age, diabetes, and sex.

Results: Forty-nine PD patients were enrolled, 53.1% (n = 26) women; mean age, 55.5 ± 16.3 years. There were significant correlations between PhA and SPPB (r = 0.550, p < 0.001), time of 4-m gait test (r = −0.613, p < 0.001) and sit-to-stand test and (r = −0.547, p < 0.001). Overhydration index was significantly correlated with SPPB, 4-m gait test (r = 0.339, p = 0.017), and sit-to-stand test (r = 0.335, p = 0.019). Inflammatory markers were not significantly correlated with physical function parameters. In the multiple linear regression analysis, PhA was associated with physical function parameters, even after adjustments. Overhydration index was associated with all physical function tests only in the models with no adjustments.

Conclusion: PhA was independently associated with physical function in PD patients. Inflammatory markers and overhydration index were not associated with physical function.

Predialysis fluid overload and gait speed: a repeated measures analysis among patients on chronic dialysis

BACKGROUND

Slow gait speed is associated with hospitalization and death. We examined whether predialysis fluid overload contributes to gait speed impairment.

METHODS

We measured predialysis gait speed at baseline and 12 and 24 months among 298 patients recruited in the A Cohort Study to Investigate the Value of Exercise in ESRD/Analyses Designed to Investigate the Paradox of Obesity and Survival in ESRD. We used multivariable linear mixed modeling to examine associations between patient data and gait speed. We then added either bioimpedance-estimated volume of predialysis fluid overload or volume of delivered ultrafiltration to ascertain whether fluid excess was associated with gait speed and its trajectory. We also tested whether fluid overload change with time was predictive of gait speeds.

RESULTS

The mean baseline gait speed was 1.01 m/s and it declined by an average of 0.08 m/s/year. Older age, nonwhite race, Hispanic ethnicity, diabetes, recent fall, recent hospitalization, tobacco use and lower serum albumin were associated with slower gait speed. Each liter of predialysis fluid overload was associated with a 0.02 m/s slower gait speed [95% confidence interval (CI) 0.01-0.04, P = 0.008] and 0.05 m/s additional slowing per year (95% CI 0.03-0.06, P < 0.0001). Higher ultrafiltration volumes were associated with 0.07 m/s slower gait speed per 3% body weight removed (0.002-0.14, P = 0.045) but not with gait speed trajectory (P = 0.08). Patients who increased fluid overload walked 0.08 m/s slower compared with those who decreased fluid overload (95% CI 0.003-0.15, P = 0.04).

CONCLUSIONS

Predialysis fluid overload was associated with slower gait speed and gait speed decline over time. Interventions that limit fluid overload may lead to improvements in physical performance.

Haemodialysis patients have worse postural balance with an associated risk of falls

INTRODUCTION

Postural balance is the result of a complex interaction of sensory input which keeps us upright. Haemodialysis patients have alterations which can lead to postural instability and a risk of falls. Our objective was to analyse postural stability and its relationship with the risk of falls in haemodialysis patients using a force platform.

MATERIAL AND METHODS

This was a prospective cross-sectional study. Postural balance was recorded using a force platform in prevalent haemodialysis patients. We collected epidemiological, dialysis, analytical and treatment data. The incidence of falls was recorded over the 6 months following the tests. The postural stability analysis was performed with a portable strain gauge platform (AMTI AccuGait®) and a specific software unit for stabilometry (Balance Trainer® program). We measured 31 balance parameters; the balance variables used were: Area95; AreaEffect; VyMax; Xrange and Yrange. The stabilometry studies were performed in 3 situations: with eyes open; with eyes closed; and with the patient performing a simultaneous task. We performed one study at the start of the dialysis session, and a second study at the end. Stabilometry was measured in a control group under similar conditions.

RESULTS

We studied 32 patients with a mean age of 68 years old; of this group, 20 subjects were male and 12 were female. Their mean weight was 74kg, with a mean BMI of 27.6kg/m². In the controls, there were no significant differences in the stabilometry between the 3 situations studied. Both pre- and post-haemodialysis, patients with closed eyes showed greater imbalance, and there were significant differences with the other situations and controls. We found a significant increase in instability after the haemodialysis session, and greater instability in the 13 patients with diabetes (P<.05). The 4 patients with hyponatraemia (Na<136mmol/l) had worse balance in the simultaneous task situation (P=.038). Various drugs, such as insulin (P=.022), antiplatelet agents (P=.036) and beta-blockers (P=.029), were associated with imbalance. The 10 patients who suffered falls had greater imbalance, Yrange, Xrange, Area95 and AreaEffect, both pre- and post-haemodialysis (P<.05) than those without falls.

CONCLUSIONS

Haemodialysis patients have alterations which can lead to postural instability and a risk of falls. Prevention programmes which include specific exercises to improve balance could be beneficial in reducing the risk of falls in this population.

Relation of Admission Blood Pressure to In-hospital and 90-Day Outcomes in Patients Presenting With Transient Ischemic Attack

The association between admission blood pressure (BP) and outcomes in patients with transient ischemic attack (TIA) is not well defined. Patients in the United States national Get With The Guidelines-Stroke registry with a TIA were included. Admission systolic and diastolic BP was used to compute mean arterial pressure and pulse pressure (PP). A subset of this cohort was linked to Centers for Medicare and Medicaid claims data for postdischarge outcomes. The in-hospital outcomes of interest were: mortality, not discharged home, and inability to ambulate independently at discharge. Postdischarge, 30-day and 90-day outcomes of interest were mortality, readmission for stroke, and readmission for major cardiovascular event-composite of death, cerebrovascular, or cardiovascular readmission. Among the 218,803 patients with TIA, lower admission systolic blood pressure (SBP) was associated with worse in-hospital outcomes. Compared with patients with SBP of 150 mm Hg, a lower SBP of 120 mm Hg was associated with higher risk of in-hospital death (adjusted OR = 1.79; 95% CI = 1.50 to 2.12), not being discharged home (adjusted OR = 1.31; 95% CI = 1.27 to 1.36), or inability to ambulate independently at discharge (adjusted OR = 1.27; 95% CI = 1.23 to 1.31). Similarly, among the 64,352 patients in the Centers for Medicare and Medicaid-linked cohort, an inverse association between systolic BP and postdischarge mortality (p <0.0001), and major cardiovascular event (p = 0.0001) was observed at 30-days and at 90-days postdischarge. However, there was no relation between SBP and readmission for stroke either at 30-days (p = 0.35) or at 90-days (p = 0.11). Results were largely similar for diastolic BP, mean arterial pressure, PP, and outcomes. In conclusion, in patients with a transient ischemic attack, a BP paradox was observed, with higher admission BP associated with improved in-hospital, 30-day, and 90-day postdischarge outcomes.

Is there a relationship between plantar foot sensation and static balance, physical performance, fear of falling, and quality of life in hemodialysis patients?

INTRODUCTION

This study was conducted to investigate the relationship between plantar foot sensation and static balance, physical performance, fear of falling, and quality of life in hemodialysis patients.

MATERIALS AND METHODS

The study involved 24 hemodialysis patients and 20 healthy volunteers. Light touch-pressure sensation (Semmes Weinstein Monofilament test kit), two-point discrimination sensation (esthesiometer) and vibration sensation (128 Hz diapason) were used to evaluate plantar foot sensation. Static balance was assessed by the one-leg standing balance test, physical performance by the Timed Up and Go test, fear of falling with the Fall Efficacy Scale, and quality of life with the Ferrans and Powers Quality of Life Index Dialysis Version.

FINDINGS

There was a significant difference in plantar foot sensation, static balance, and physical performance of the patients compared to the healthy controls (P < 0.05). There was a strong correlation between static balance and physical performance with foot sensation in the hemodialysis patients (P < 0.05). There was also a strong correlation between static balance, physical performance, and fear of falling in hemodialysis patients (P < 0.05). The correlation between static balance, physical performance, and quality of life in the hemodialysis patients was strong (P < 0.05).

DISCUSSION

The most important result of this study is that light touch-pressure sensation, vibration sensation, two-point discrimination sensation, static balance, and physical performance, all of which involve the activity of cutaneous sensory receptors on the sole of the foot, are reduced in individuals who undergo hemodialysis. The findings of this study suggest potential rehabilitation strategies that could be applied to this patient group.

Pre-Kidney Transplant Lower Extremity Impairment and Post-Kidney Transplant Mortality

Prediction models for post-kidney transplantation mortality have had limited success (C-statistics ≤0.70). Adding objective measures of potentially modifiable factors may improve prediction and, consequently, kidney transplant (KT) survival through intervention. The Short Physical Performance Battery (SPPB) is an easily administered objective test of lower extremity function consisting of three parts (balance, walking speed, chair stands), each with scores of 0-4, for a composite score of 0-12, with higher scores indicating better function. SPPB performance and frailty (Fried frailty phenotype) were assessed at admission for KT in a prospective cohort of 719 KT recipients at Johns Hopkins Hospital (8/2009 to 6/2016) and University of Michigan (2/2013 to 12/2016). The independent associations between SPPB impairment (SPPB composite score ≤10) and composite score with post-KT mortality were tested using adjusted competing risks models treating graft failure as a competing risk. The 5-year posttransplantation mortality for impaired recipients was 20.6% compared to 4.5% for unimpaired recipients (p < 0.001). Impaired recipients had a 2.30-fold (adjusted hazard ratio [aHR] 2.30, 95% confidence interval [CI] 1.12-4.74, p = 0.02) increased risk of postkidney transplantation mortality compared to unimpaired recipients. Each one-point decrease in SPPB score was independently associated with a 1.19-fold (95% CI 1.09-1.30, p < 0.001) higher risk of post-KT mortality. SPPB-derived lower extremity function is a potentially highly useful and modifiable objective measure for pre-KT risk prediction.

Functional Status Modifies the Association of Blood Pressure with Death in Elders: Health and Retirement Study

OBJECTIVE

To examine whether grip strength, gait speed, and the combination of the two physical functioning measures modified the association of systolic BP (SBP) and diastolic BP (DBP) with mortality.

DESIGN

Nationally representative cohort study.

SETTING

Health and Retirement Study.

PARTICIPANTS

7,492 U.S. adults aged ≥65 years.

MEASUREMENTS

Grip strength was measured by a hand dynamometer and classified as normal (≥16 kg for female; ≥26 kg for male) and weak. Gait speed was assessed over a 98.5-inch walk and classified as non-slow (≥0.60 m/s for female; ≥0.52 m/s for male) and slow.

RESULTS

Over an average follow-up time of 6.0 years, 1,870 (25.0%) participants died. After adjustment for socio-demographic, behavioral, and clinical measures, elevated SBP (≥150 mmHg) and DBP (≥90 mmHg) was associated with a 24% (95% CI, 7-43%) and 25% (95% CI, 5-49%) higher mortality among participants with normal grip strength. In contrast, elevated SBP and DBP was associated with a 6% (95% CI, 31 to -27%) and a 16% (95% CI, 46 to -26%) lower mortality among those with weak grip strength (P-values of interactions: both=.07). The inverse relations between BP with death were most pronounced among slow walkers with weak grip strength. The HRs of elevated SBP and DBP for death was 0.85 (95% CI, 0.56-1.29) and 0.53 (95% CI, 0.30-0.96), respectively, and was substantially different from non-slow walkers with normal grip strength (HR = 1.24 and 1.15, respectively; P-values of interactions: both <.001). Therefore, associations of BP with death varied modestly by gait speed.

CONCLUSION

Grip strength modified the association of BP with death. Combination of grip strength and gait speed has incremental value for modifying the association of BP with death.

Blood Pressure in Older Adults: the Importance of Frailty

The importance of high blood pressure (BP) and the effect of BP lowering in older adults remain controversial due to the mixed evidence in this population. Frailty status may resolve the apparently conflicting findings and identify subpopulations who share common risk. Emerging evidence demonstrates that low BP is associated with poor outcomes in older frail adults or those with poor functional status. In contrast, in non-frail older adults, low BP appears beneficial. Frail older adults may be at increased risk of hypotension, serious fall injuries, and polypharmacy. Additionally, peripheral BP may not be the best prognostic measure in this population. The majority of clinical practice guidelines give little recommendation for frail older adults, which is likely due to their systematic underrepresentation in randomized controlled trials. Future studies need to consider modifications to safely include frail older adults, and guidelines should consider inclusion of evidence beyond randomized controlled trials.