Clinical Characteristics and Kidney Outcomes in Chinese Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

The management of autosomal dominant polycystic kidney disease (ADPKD) remains challenging with variable and uncertain genotype-phenotype correlations. The Mayo clinic imaging classification allows a more accurate risk stratification but is limited by the atypical imaging patterns. We aim to assess the clinical characteristics and the morphology of the cystic kidneys in a cohort of Chinese patients with ADPKD.

METHOD

Ninety-eight patients with ADPKD were recruited prospectively from August 2019 to December 2020 in Prince of Wales Hospital, Hong Kong. They were subsequently followed up every 6 months for a minimum of2 years. We reviewed the clinical characteristics and MRI imaging patterns at baseline and the kidney outcome at the end of the follow-up. Atypical imaging patterns included unilateral; segmental; asymmetric; lopsided and bilateral atrophy as defined by the Mayo Imaging Classification.

RESULT

Mean age was 51.5 ± 14.3 years old and the mean eGFR 68.7 ± 27.5 ml/min per 1.73 m2. The ninety-eight patients included 36 males:62 females. Seventy-six patients (77.6%) had a family history. Seventeen of the 98 (17.3%) patients had atypical imaging patterns. Compared to typical cases, atypical cases were older at the time of diagnosis (49.5 ± 16.0 vs 33.0 ± 13.0 years, p<0.001), at the time of starting antihypertensive medications (52.4 ± 14.8 vs 39.7 ± 11.0 years, p=0.001) and less likely to have a positive family history (58.8% vs 81.5%, p=0.042). Patients with atypical patterns showed a lower eGFR decline as compared to those with the typical pattern (-0.86 ± 4.34 vs -3.44 ± 4.07 ml/min per 1.73m2/year, p=0.022).

CONCLUSION

In this cohort of Chinese patients with ADPKD, an atypical imaging pattern was observed in 17% of the cases, associated with later presentation and a milder disease course. Future genotyping studies will help to define the genetic architecture and the basis for the phenotypic spectrum in Chinese ADPKD patients.

The prognostic value of reduced global longitudinal strain (GLS) on cardiac outcomes in patients on peritoneal dialysis: a prospective study

Funding Acknowledgements

Type of funding sources: None.

Introduction

This study aims to evaluate the capacity of left ventricular global longitudinal strain (GLS) in end stage renal failure patients on peritoneal dialysis (PD) to predict cardiovascular mortality and major adverse cardiac events (MACE). GLS has been an established parameter in detecting subclinical left ventricular systolic dysfunction in the setting of preserved ejection fraction (EF &gt; = 50%). We hypothesized that reductions of GLS (i.e. less negative value) are associated with adverse cardiovascular outcome.

Methods

We prospectively recruited a total of 60 PD patients from a single dialysis center in a tertiary hospital. GLS was determined by two-dimensional speckle-tracking echocardiography, under Philips QLab system. A less negative value reflects underlying subclinical LV dysfunction. The primary outcome was 4-point MACE, which was a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke and hospitalization for heart failure. Surrogate markers of inflammation (C-reactive protein [CRP], tumor necrosis factor [TNF]-alpha), nutrition (serum albumin), arterial stiffness (pulse wave velocity [PWV]), and serum N-terminal pro-brain natriuretic peptide (NT-proBNP) were also measured.

Results

16 (26.7%) and 34 (56.7%) PD patients had reduced GLS (≥ -18.3%) and left ventricular hypertrophy (LVH) respectively. In 12-month follow up, 4-point MACE occurred in 13.6% and 59.8% of normal and compromised GLS patients respectively (log-rank, P = 0.004), as illustrated by Kaplan-Meier curves (Fig 1). Patients with reduced GLS had higher proportion of uncontrolled blood pressure and higher prevalence of coronary artery disease. Their EF were significantly lower (53.6 ± 7.4% vs. 61.3 ± 4.1%, P= 0.001) compared with patients with normal GLS. In addition, GLS correlated with EF (r = -0.57, P &lt;0.0001) and PWV (r= 0.33, P = 0.01). There was a trend towards an association between GLS and ln(CRP) (r= 0.25, P = 0.057), and ln(NT-proBNP) (r = 0.22, P= 0.09), respectively.

Conclusions

Subclinical LV systolic dysfunction was present in one-fourth of peritoneal dialysis patients despite having preserved EF. Reduced GLS (less negative than 18.3%, illustrated in Fig 2) is a strong predictor of poor cardiovascular prognosis among PD population. Abstract Figure 1  Abstract Figure 2

Impact of frailty and its inter-relationship with lean tissue wasting and malnutrition on kidney transplant waitlist candidacy and delisting

BACKGROUND & AIMS

Frailty and body composition contribute to adverse pre-transplant outcomes including hospitalization and waitlist mortality, but the interaction between frailty and body composition remains uncertain.

METHODS

Frailty was diagnosed by Clinical Frailty Scale (CFS) and a standard Frailty Questionnaire (FQ). Nutrition was evaluated by serum albumin level, subjective global assessment (SGA) and comprehensive malnutrition-inflammation score (MIS). Body composition was assessed by bioimpedance spectroscopy. All patients were followed up for three years. Primary outcome measure was a composite of death and permanent removal from waitlist. Secondary outcomes were emergency room attendance and hospitalization.

RESULTS

432 prevalent peritoneal dialysis (PD) patients were recruited. 148 (34.3%) were listed on transplant waitlist. Frailty, age and comorbidity load predicted waitlisting. With time, 47 patients were delisted. Frailty by FQ (p = 0.028), serum albumin level (p = 0.005) and waist circumference (p = 0.010) predicted delisting after adjustment for confounders. Frailty significantly interacted with lean tissue wasting (FQ: p = 0.002, CFS: p = 0.048), and MIS (FQ: p = 0.004; CFS: p = 0.014) on delisting. Lean tissue wasting caused 2.56 times risk of delisting among frail individuals identified by FQ (p = 0.016), while serum albumin and the presence of diabetes mellitus predicted the risk of delisting among non-frail individuals. Lean tissue wasted and frail subjects had a higher all-cause and infection-related hospitalization.

CONCLUSION

Frailty predicted both kidney transplant waitlisting and subsequent delisting. Frailty interacted with body composition on transplant waitlist delisting. Lean tissue wasting and malnutrition independently predicted delisting in frail and non-frail listed subjects respectively.

Progression in Physical Frailty in Peritoneal Dialysis Patients

BACKGROUND

Physical frailty contributes to adverse clinical outcomes in peritoneal dialysis (PD) patients. Little has been reported about frailty transitions in this population. We aimed to describe the transitions of frailty in PD patients and identify factors that predicted changes in frailty state.

METHODS

In a prospective observational study, we recruited 267 PD patients. Frailty was assessed by a validated frailty score. Depression was graded by PHQ-9 score, and nutritional status was evaluated by serum albumin, Subjective Global Assessment (SGA), and comprehensive Malnutrition Inflammation Score (MIS). The primary outcome was the change in frailty score at follow-up compared to baseline.

RESULTS

At baseline, 194 (72.7%) patients were classified as frail. With time, their frailty scores significantly increased (p < 0.001), and 93 of the surviving subjects (78.2%) were classified as frail. There was a modest significant correlation between change in MIS (p < 0.001), change in SGA score (p < 0.001), and change in PHQ-9 score (p < 0.001) with change in frailty score. An increase in PHQ-9 score (p < 0.001) and MIS (p = 0.001), as well as longer duration of hospitalization (p = 0.001), was independently associated with a greater change in frailty score after adjustment for confounding factors. Frailty score was also improved in patients who were converted to hemodialysis (p = 0.048) and received renal transplantation (p = 0.005).

CONCLUSION

Our findings suggested that frailty transitions were common in PD patients. Worsening in nutrition and depression, together with a longer duration of hospitalization, were associated with worsening in frailty.

Interaction between central obesity and frailty on the clinical outcome of peritoneal dialysis patients

BACKGROUND

Frailty and obesity contribute to the adverse clinical outcome of peritoneal dialysis (PD) patients, but the interaction between frailty and obesity remains uncertain.

OBJECTIVE

To examine the interaction between frailty and obesity on the clinical outcome of PD patients.

DESIGN

Single centre prospective observational cohort study.

PATIENTS

267 prevalent Chinese PD patients were recruited.

MEASUREMENTS

Frailty was identified by a standard score. General and central obesity were determined by body mass index (BMI) and waist-hip ratio (WHR), respectively. Body composition was assessed by bioimpedance spectroscopy. All patients were followed for two years. Outcome measures included all-cause as well as cardiovascular mortality and hospitalization.

RESULTS

Of the 267 patients, 120 (44.9%) were frail. Frail individuals were more likely to have central obesity (p < 0.001) but not general obesity. Although WHR did not predict patient survival, there was a significant interaction between WHR and frailty on patient survival and cardiovascular survival (p = 0.002 and p = 0.038, respectively). For patients without frailty, the two-year cardiovascular survival was 91.3% and 74.4% for those with and without central obesity, respectively (p = 0.002). For patients with frailty, however, the two-year cardiovascular survival was 64.6% and 66.7% for those with and without central obesity, respectively (p = 0.6). For patients without frailty, the number of hospital admission for cardiovascular disease over 2 years were 0.12 ± 0.37 and 0.34 ± 0.72 for those with and without central obesity, respectively (p = 0.03). For frail patients, however, the number of hospital admission was similar between those with and without central obesity.

CONCLUSION

There is a significant interaction between frailty and central obesity on the outcome of PD patients. The protective role of central obesity is only apparent in PD patients without frailty but not the frail ones, and there is a little prognostic value of general (non-central) obesity.

Longitudinal Changes of NF-κB Downstream Mediators and Peritoneal Transport Characteristics in Incident Peritoneal Dialysis Patients

The role of intra-peritoneal mediators in the regulation peritoneal transport is not completely understood. We investigate the relation between longitudinal changes in dialysis effluent level of nuclear factor kappa-B (NF-κB) downstream mediators and the change in peritoneal transport over 1 year. We studied 46 incident PD patients. Their peritoneal transport characteristics were determined after starting PD and then one year later. Concomitant dialysis effluent levels of interleukin-6 (IL-6), cyclo-oxygenase-2 (COX-2) and hepatocyte growth factor (HGF) are determined. There were significant correlations between baseline and one-year dialysis effluent IL-6 and COX-2 levels with the corresponding dialysate-to-plasma creatinine level at 4 hours (D/P4) and mass transfer area coefficient of creatinine (MTAC). After one year, patients who had peritonitis had higher dialysis effluent IL-6 (26.6 ± 17.4 vs 15.1 ± 12.3 pg/ml, p = 0.037) and COX-2 levels (4.97 ± 6.25 vs 1.60 ± 1.53 ng/ml, p = 0.007) than those without peritonitis, and the number of peritonitis episode significantly correlated with the IL-6 and COX-2 levels after one year. In contrast, dialysis effluent HGF level did not correlate with peritoneal transport. There was no difference in any mediator level between patients receiving conventional and low glucose degradation product solutions. Dialysis effluent IL-6 and COX-2 levels correlate with the concomitant D/P4 and MTAC of creatinine. IL-6 and COX-2 may contribute to the short-term regulation of peritoneal transport.

Depression and Physical Frailty Have Additive Effect on the Nutritional Status and Clinical Outcome of Chinese Peritoneal Dialysis

BACKGROUND/AIMS

Frailty and depression both contribute to malnutrition and adverse clinical outcome of peritoneal dialysis (PD) patients. However, their interaction is incompletely defined.

METHODS

We studied 178 adult Chinese PD patients. Physical frailty was assessed by a validated in-house questionnaire; depressive symptoms was screened by the Geriatric Depression Scale; nutritional status was determined by subjective global assessment (SGA) and malnutrition inflammation score (MIS). All patients were followed for up to 24 months for survival and hospitalization analysis.

RESULTS

There were 111 patients (62.4%) physically frail, amongst those 48 (43.2%) had depressive symptoms. Only 1 patient had depressive symptoms without frailty. There was an additive effect of depressive symptoms and physical frailty on nutritional status. For the groups with no frailty, frail but no depressive symptoms, and frail with depressive symptoms, serum albumin decreased in a stepwise manner (35.8 ± 5.6, 34.9 ± 4.4, and 32.9 ± 5.3 g/L, respectively, p=0.025); overall SGA score was 5.75 ± 0.61, 5.41 ± 0.59, and 5.04 ± 0.77, respectively (p< 0.0001), and MIS was 5.12 ± 2.30, 7.13 ± 3.22, and 9.48 ± 3.97, respectively (p< 0.0001). At 24 months, patient survival was 86.6%, 71.4%, and 62.5% for patients with no frailty, frail but no depressive symptoms, and frail with depressive symptoms, respective (p=0.001). The median number of hospital stay was 8.04 (inter-quartile range [IQR] 0.91 - 19.42), 14.05 (IQR 3.57 - 37.27), and 26.62 (IQR 10.65 - 61.18) days per year of follow up, respectively (p< 0.0001).

CONCLUSION

Physical frailty and depressive symptoms are both common in Chinese PD patients, and they have additive adverse effect on the nutritional status and clinical outcome.

Current Challenges and Opportunities in PD

Despite the gradual increased use of peritoneal dialysis (PD) globally around the world, it is recognized that a number of areas in PD as a renal-replacement therapy require attention and improvements. The current challenges in PD include how to tackle technique failure and sustain long-term PD, manage and prevent peritoneal infections, malnutrition and inflammation, cardiovascular mortality, volume overload, glucose exposure, adequacy of solute removal, peritoneal access, peritoneal physiology and changes with long-term PD, patient fatigue, psychosocial issues, and care of elderly patients on PD. Obviously, hemodialysis as another renal-replacement therapy modality also has its own areas that need attention and improvement by nephrologists and nurses. With more clinical and basic science research, outcome studies, and through better education and training, together with the implementation of global PD guidelines for enhancing care of PD patients, it is likely that such problem areas in PD gradually will be resolved and PD patient outcomes will be improved.

Peritoneal Dialysis Catheter Revision and Replacement by Nephrologist for Peritoneal Dialysis Catheter Malfunction

BACKGROUND

Catheter malfunction is an important cause of technique failure for peritoneal dialysis (PD) patients, and is commonly managed by surgeons or intervention radiologists. We reviewed our experience in catheter revision or replacement by nephrologists.

METHOD

We reviewed the clinical outcome and complication rate of 95 consecutive patients who had PD catheter malfunction, with catheter revision or replacement by nephrologist.

RESULT

Amongst the 95 patients, 32 had catheter revision, 24 catheter replacement via the original wound, and 39 catheter replacement via a new mini-laparotomy wound. Catheter survival was 71.6% at 1 month and 48.4% at 6 months; technique survival was 88.4% at 1 month and 77.4% at 6 months. When the 3 types of procedure were analyzed separately, technique survival at 1 month was 96.8, 75.0, and 89.7%, respectively, for patients who received catheter revision, catheter replacement via the original wound, and catheter replacement via a new mini-laparotomy wound (p = 0.0002), although their catheter survival rates were not significantly different. Also, 2 patients had bleeding that required urgent surgical exploration, 2 had wound infection, and 8 had peritonitis within 4 weeks after the surgery.

CONCLUSION

PD catheter revision and replacement by nephrologist has an acceptable catheter survival and a reasonable complication rate. Given that prompt intervention is an important consideration, catheter revision and replacement by nephrologist is a suitable method for the management of catheter malfunction.

Peritoneal Dialysis in Asia

BACKGROUND

There is a growing demand of dialysis in Asia for end-stage renal failure patients. Diabetes mellitus is the leading cause of end-stage renal failure in many countries in Asia.

SUMMARY

The growth of peritoneal dialysis (PD) in Asia is significant and seeing a good trend. With the enhanced practices of PD, the quality of care in PD in Asia is also improved. Overall, PD and hemodialysis (HD) are comparable in clinical outcome. There is a global trend in the reduction of peritonitis rates and Asian countries also witness such improvement. The socio-economic benefits of PD for end-stage renal failure patients in both urban and rural areas in the developed and developing regions of Asia are an important consideration. This can help to reduce the financial burden of renal failure in addressing the growing demand of patients on dialysis. Initiatives should be considered to further drive down the cost of PD in Asia.

KEY MESSAGES

Growing demand for dialysis by an increasing number of end-stage renal failure patients requires the use of a cost-effective quality dialysis modality. PD is found to be comparable to HD in outcome and quality. In most countries in Asia, PD should be more cost-effective than HD. A 'PD-first' or a 'PD as first considered therapy' policy can be an overall strategy in many countries in Asia in managing renal failure patients, taking the examples of Hong Kong and Thailand.

FACTS FROM EAST AND WEST

(1) PD is cheaper than HD and provides a better quality of life worldwide, but its prevalence is significantly lower than that of HD in all countries, with the exception of Hong Kong. Allowing reimbursement of PD but not HD has permitted to increase the use of PD over HD in many Asian countries like Hong Kong, Vietnam, Taiwan, Thailand, as well as in New Zealand and Australia over the last years. In the Western world, however, HD is still promoted, and the proportion of patients treated with PD decreases. Japan remains an exception in Asia where PD penetration is very low. Lack of adequate education of practitioners and information of patients might as well be reasons for the low penetration of PD in both the East and West. (2) Patient survival of PD varies between and within countries but is globally similar to HD. (3) Peritonitis remains the main cause of morbidity in PD patients. South Asian countries face specific issues such as high tuberculosis and mycobacterial infections, which are rare in developed Asian and Western countries. The infection rate is affected by climatic and socio-economic factors and is higher in hot, humid and rural areas. (4) Nevertheless, the promotion of a PD-first policy might be beneficial particularly for remote populations in emerging countries where the end-stage renal disease rate is increasing dramatically.

Long-term outcome of biopsy-proven minimal change nephropathy in Chinese adults

BACKGROUND

Minimal change nephropathy is a common cause of primary nephrotic syndrome in adults. However, there are few studies of its clinical course, response to treatment, and long-term outcome.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

340 consecutive adult patients with nephrotic syndrome and biopsy-proven minimal change nephropathy treated in a university hospital from 1984 until 2004.

FACTORS

Treatment response groups: primary steroid resistance, frequent relapse (≥4 relapses within 1 year), infrequent relapse (≥1 relapse but not frequent relapse), and no relapse (reference group); disease pattern.

OUTCOME

Medical problems after diagnosis; patient survival; renal survival.

RESULTS

Median time to remission was 10 (IQR, 8-12) weeks; 179 (52.6%) had no relapse, 42 (12.4%) had infrequent relapses, 86 (25.3%) were frequent relapsers or steroid dependent, and 33 (9.7%) had primary steroid resistance. After a median follow-up of 174.7 (IQR, 119.7-235.0) months, 32 patients developed end-stage renal disease and 62 died (25 after progression to end-stage renal disease). Cox regression analysis showed that age and treatment response groups were the independent predictors of patient survival. Compared to the no-relapse group, the infrequent-relapse group had significantly better patient survival (adjusted HR, 0.19; 95% CI, 0.08-0.44; P<0.001), whereas the primary-steroid-resistance group had significantly worse patient survival (adjusted HR, 5.87; 95% CI, 1.83-18.85; P<0.001). Renal survival was excellent except in the primary-steroid-resistance group.

LIMITATIONS

Retrospective study.

CONCLUSIONS

A substantial proportion of adult patients with minimal change nephropathy continue to have disease flares more than 10 years after the initial presentation, and medical problems after diagnosis are common.

Bioimpedance spectroscopy for the detection of fluid overload in Chinese peritoneal dialysis patients

BACKGROUND

Fluid overload probably contributes to the cardiovascular risk of peritoneal dialysis (PD) patients. We studied the relationship between over-hydration as determined by bioimpedance spectroscopy and dialysis adequacy, nutritional status, and arterial stiffness in Chinese PD patients.

METHODS

We studied 122 asymptomatic prevalent PD patients: bioimpedance spectroscopy, arterial pulse wave velocity, dialysis adequacy and nutritional status were determined.

RESULTS

Of the 122 patients, 88 (72.1%) had over-hydration of ≥ 1 L, while 25 (20.5%) were ≥ 5 L. Over-hydration significantly correlated with total body water (r = 0.474, p < 0.001) and extracellular water (r = 0.755, p < 0.001). Over-hydration was more severe in male and diabetic patients, and significantly correlated with Charlson's comorbidity score, blood pressure, body mass index, body weight, peritoneal transport characteristics, and carotid-femoral pulse wave velocity. Over-hydration significantly correlated with Kt/V (r = -0.287, p = 0.016), serum albumin level (r = -0.465, p < 0.001) and malnutrition inflammation score (r = 0.410, p = 0.006), but not residual renal function.

CONCLUSION

Over-hydration is common in asymptomatic Chinese PD patients. The degree of over-hydration is particularly pronounced in patients who are inadequately dialyzed, have multiple comorbid conditions and low serum albumin levels. Over-hydration is associated with high blood pressure and arterial stiffness, and may contribute to the excessive risk of cardiovascular disease in this group of patients.

Outcome of Hemodialysis Patients Who Had Failed Peritoneal Dialysis

<i>Background:</i> Peritoneal dialysis (PD) and hemodialysis (HD) are often regarded as equivalent choices of renal replacement therapy. However, little is known about the outcome of patients who failed PD and converted to long-term HD. <i>Methods:</i> We reviewed 197 patients who received long-term HD after failed PD in a University hospital from 1994 to 2008 (the PD-first group) and 140 patients who received long-term HD as their initial therapy during that period (the primary-HD group). Their survival rates are compared. <i>Results:</i> The two groups are highly comparable in terms of baseline demographic data. The PD-first group required more temporary dialysis catheters than the primary-HD group (3.1 ± 3.4 vs. 1.5 ± 1.8, p < 0.0001). At 5 years, the actuarial survival of the PD-first group was significantly lower than that of the primary-HD group (39.9 vs. 59.7%, p < 0.0001), while technique survival was similar (30.4 vs. 30.1%, p = 0.7). When analysis on actuarial survival was performed for patients who survived the first 12 months on HD, the 5-year survival became similar (65.2 vs. 68.8%, p = 0.5). During the first 12 months on HD, independent predictors of actuarial survival of the PD-first group were duration of PD, Charlson’s comorbidity score, type of permanent access and serum albumin before conversion; after 12 months, independent predictors of actuarial survival were Charlson’s comorbidity score, total Kt/V, residual renal function, fat-free edema-free body mass before conversion and baseline peritoneal transport. <i>Conclusion:</i> Patients who were converted to long-term HD after failed PD had a higher mortality than patients who used HD as the primary modality of renal replacement therapy. The excessive mortality, however, was limited to the first 12 months after conversion, and the technique survival was similar between the two groups. Vascular access is a common problem in patients who failed PD.

Persistent symptomatic intra-abdominal collection after catheter removal for PD-related peritonitis

BACKGROUND

Peritoneal dialysis (PD) patients with severe peritonitis require catheter removal. It is often assumed that this approach, together with antibiotics, would eradicate the infection; however, some patients continue to have problems despite catheter removal.

METHOD

We reviewed 30 consecutive PD patients in our center from 1997 to 2008 with recurrent loculated peritoneal collection after catheter removal for severe peritonitis.

RESULTS

Of the 1928 episodes of peritonitis that occurred in 702 patients during the study period, 11.1% required catheter removal and 1.6% developed recurrent peritoneal collection that required percutaneous drainage. Median time to diagnosis of intra-abdominal collection was 12 days after catheter removal (interquartile range 7 - 61 days). In 25 patients (83.3%), aspirate of the abdominal collection was culture negative. In 17 patients (56.7%), the abdominal collection was recurrent and required repeated percutaneous aspiration. Only 3 patients had successful reinsertion of the peritoneal catheter but all had reduced small solute clearance after returning to PD.

CONCLUSION

A small but not negligible proportion of patients with PD-related peritonitis develop recurrent intra-abdominal collection that requires percutaneous drainage after catheter removal. The chance of a successful return to PD is very low in this group of patients. Direct conversion to long-term hemodialysis may avoid unnecessary attempts at peritoneal catheter reinsertion.