Ahmed Chaaban

GFR estimation in the morbidly obese pre- and postbariatric surgery: one size does not fit all

BackgroundGlomerular hyperfiltration commonly associated with obesity is expected to improve postbariatric surgery. However, formula-based glomerular filtration rate (GFR) estimation in these patients is limited by body size confounders necessitating use of modified equations, the reliability of which remains uncertain.MethodsIn this study, various GFR-estimating formulae were compared in morbidly obese patients at baseline and postbariatric surgery. Through a retrospective chart review, we identified 220 patients who had undergone this procedure, with over 6-month follow-up, during which major weight reduction was achieved.ResultsA significant decrease in BP and glomerular hyperfiltration was observed, though there was large variability in GFR estimation using the different formulae. Gross over and underestimation was observed which improved with correction for body size confounders especially lean body weight (LBW). Postoperatively, significant attenuation in estimated GFR was demonstrated when LBW or body surface area-adjusted versions were used. In a subgroup of patients with chronic kidney disease, a significant improvement in GFR was seen postoperatively with the LBW-modified formula but there were again inconsistencies when using other equations.ConclusionThough clinicians must be critical in the application of GFR estimates to patient care, LBW adjustment appears to be the most practical solution to its estimation in the obese patients. This is particularly true for patients with normal renal function but appears to be also applicable to those with compromised kidney function. Future studies are needed to compare these equations with a gold standard GFR measure as well as to explore whether the renal benefits from bariatric surgery are sustained or seen in more advanced CKD stages.

Potassium Binders in Hemodialysis Patients: A Friend or Foe?

There is insufficient evidence on the utility of potassium-binding resins in patients with end-stage renal disease on dialysis. In addition, their poor tolerability raises concerns of patient adherence. We aimed to assess the efficacy of calcium resonium and investigate the impact of counseling on adherence pattern as well as treatment response. Adult patients on hemodialysis receiving calcium resonium were enrolled with a control group not on treatment. Adherence patterns and adverse effects were recorded following patient interviews. Patients were stratified into 28 adherent (A), 42 non-adherent (NA), and 30 controls (C). Patient education was undertaken, and serum potassium levels were evaluated for 3 months pre- and post-counseling with inter- and intra-group comparison. A statistically significant difference was observed between potassium levels at baseline in A and NA groups but not post-education, which was related to worsening control in former and not due to improvement in NA patients. The poor effectiveness of calcium resonium in the control of hyperkalemia was likely related to non-compliance due to gastrointestinal (GI) intolerability. Dietary indiscretions as well as lack of consistent use of cathartics may have also contributed. No difference in dialysis adequacy was noted among groups, although the contribution of residual renal function was not assessed. These findings raise concern regarding cost-efficacy of this medication and lend credence to investing in traditional measures in hyperkalemia management, namely dietary compliance and adequate dialysis. Further long-term trials are awaited to better define the role of calcium resonium in the dialysis setting.

Renal biomarkers for assessment of kidney function in renal transplant recipients: how do they compare?

Accurate assessment of renal function is of key importance, given its prognostic value. However, gold standard measures are cumbersome, and serum creatinine itself is an insensitive predictor, especially in renal transplant recipients. Though GFR-estimating formulae have been relied upon, they do have their own limitations. Nevertheless, renal biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C, among others, are now emerging as potentially useful indicators of GFR. We aimed to evaluate the diagnostic performance of NGAL versus cystatin C and eGFR using CKD-EPI, MDRD and cystatin C in renal transplant recipients and non-transplant CKD patients. We found a significant correlation between NGAL, serum creatinine, cystatin C and eGFR. The latter parameters were also strong predictors of serum NGAL levels. However, performance of NGAL, based on receiver operating characteristic curves, was inferior to that of the reference tests. It appears that in renal transplant recipients NGAL correlates well with cystatin C and eGFR, most strongly with cystatin-based formula. Though this suggests potential use of NGAL as a screening test, its weaker diagnostic performance raises some concern about its clinical usefulness. Larger studies are needed to explore this further.

Encapsulating Peritoneal Sclerosis: A Rare Complication of Peritoneal Dialysis in Al-Ain, United Arab Emirates

Encapsulating peritoneal sclerosis (EPS) is a rare complication of peritoneal dialysis (PD) with devastating consequences. Although it can occur among patients on PD, it may present long after PD has been discontinued; thus, its diagnosis depends on a high index of suspicion. We present a rare case of EPS in the United Arab Emirates with a protracted course and delays in recognizing the condition until after resolution of the acute attack. This case highlights the need for early identification of risk factors as well as the subtle features of EPS for appropriate diagnosis and perhaps even prevention; this being worth a ton of cure. A review of the literature including the latest evidence-based treatment options is also highlighted.

Renal variant of Fabry disease with sporadic GLA gene mutation: role of early renal biopsy

Fabry disease (FD) is a rare, X-linked inherited disease of glycosphingolipid metabolism due to deficiency of lysosomal α-galactosidase A activity. Scarce activity of lysosomal α-galactosidase A results in progressive accumulation of globotriaosylceramide (Gb3) within lysosomes, believed to trigger a flow of cellular changes that lead to the clinical manifestation of the disease. We present a 23-year-old male with renal variant of FD who was born from non-affected parents, which, to the best of our knowledge, has not been reported in the literature so far. In conclusion, FD can occur due to sporadic GLA gene mutation. Pure renal involvement might be associated with progressive disease which leads to end-stage renal disease within a short period. Physicians should have a high index of suspicion for FD especially in male cases with unexplained renal failure that are slowly progressive in nature, even in the absence of a clear hereditary component. Early renal biopsy is recommended in any progressive renal impairment.

Provision of renal care for patients with end stage kidney disease in persistent vegetative state, in United Arab Emirates: a national survey of renal physicians

ABSTRACT Patients with end stage kidney disease (ESKD) with severely impaired cognitive function have no survival benefit from dialysis. We therefore undertook a survey to explore the renal physicians’ practices of withholding and withdrawal of dialysis treatment in vegetative state patients in the United Arab Emirates (UAE). A cross sectional survey of 29 nephrology practices in UAE exploring physicians’ practices in making decisions of withholding and withdrawal of dialysis treatment during provision end-of-life care for patients in persistent vegetative state (PVS).The majority of participants practice in governmental non-for-profit dialysis units (79%), and think they are well prepared to make decision with patients and family on issues of dialysis withdrawal and withholding (69%). If a chronic dialysis patient became permanently unconscious only few respondents (17%) indicated probability of stopping dialysis. On the other hand, more respondents (48%) reported that dialysis is likely to be withheld in PVS patients who develop kidney failure. In high risk or poor prognosis ESKD patients and given how likely they would consider each option independently, respondents reported they are likely to consider time-limited dialysis in 78% of the time followed by stopping (46%) or forgoing (27%) dialysis. Majority of the participants perceived that their decisions in providing renal care for PVS patients in UAE were influenced by the family sociocultural beliefs (76% of participants), the current hospital policies (72% of participants), and by Islamic beliefs (66% of participants). Only few perceived access to palliative care (30%) and treatment cost (17%) to have an impact on their decision making.Decisions of initiation and continuation of dialysis treatment to ESKD patients in PVS are prevalent among nephrology practices in UAE. Development of local guidelines based on the societal values along with early integration of palliative kidney failure management care would be required to improve the quality of provision of end-of-life renal care in UAE. Abbreviations: ESKD: stage kidney disease; UAE: United Arab Emirates; PVS: persistent vegetative state; RPA: Renal Physicians Association; ASN: American Society of Nephrology; EMAN: Emirates Medical Association Nephrology Society; CPR: cardiopulmonary resuscitation.