New research was presented at SCM 22, the National Kidney Foundation 2022 Spring Clinical Meetings. The features below highlight some of the studies SCM22 that emerged from the conference.
Serum Ferritin Strongest Link With Bone Marrow Iron Stores
For a cross-sectional study, Elizabeth Nemeth, PhD, and colleagues investigated serum iron indices that were indicative of bone marrow iron stores in youth with end-stage kidney disease (ESKD) who were dialysis-dependent. “Serum iron indices are commonly monitored to guide supplemental iron and recombinant human erythropoietin administration,” Dr. Nemeth explained. The researchers collected data from patients on dialysis (mean age, 17.2 ± 4.4) who had a bone biopsy for CKD-related bone disorders. Older age, greater serum ferritin level, and higher transferrin saturation were found to each be independently associated with higher bone marrow iron stores. “In children with ESKD, greater serum ferritin remained the strongest independent correlate of greater bone marrow iron stories, followed by older age and transferrin saturation,” the study authors concluded.
Family CKD History Predicts Clinical & Molecular Findings
To determine if individuals with a familial history of CKD had different clinical characteristics and molecular diagnostic rates compared with those without a familial history, Alexander Chang, MD, MS, and colleagues evaluated 2,363 unrelated patients through the KIDNEYCODE cohort database. Among participants, approximately 13% and 14% had focal segmental glomerulosclerosis or Alport Syndrome, respectively. In addition, a family history of CKD was found in 44%. Among symptomatic individuals, those with a family history of CKD had lower eGFR ranges, were more likely to have a positive molecular diagnosis, and reported more instances of hematuria compared with those without a family history (49% vs 27%, respectively); those with a family history of CKD also had a higher likelihood of a positive molecular diagnosis (44% vs 27%, respectively). “These findings suggest that a positive family history of CKD is a predictor of clinical and molecular outcomes in the KIDNEY CODE cohort,” the study authors wrote.
Gout Common in Patients With Advanced CKD
Although the risk for gout is increased by poor renal function, the prevalence of gout and its effect on patients with advanced chronic kidney disease (CKD) has not been thoroughly investigated. To fill this knowledge gap, Leonard Stern, MD, and colleagues examined patients with stage 3-5 CKD. Criteria for gout included having gout as a comorbidity, having noted tophi/gout flares, or being on urate-lowering therapy (ULT). Those with uncontrolled gout (UCG) had at least two gout flares in the past year, serum urate greater than 6 mg/dL with tophi, and one or more swollen/tender joints. Among 746 patients, 23% had gout, of whom 13% had UCG; however, 29% did not have a gout diagnosis and 38% were not on ULT. Patients with stage 3b and 4 CKD had the highest prevalence rates for gout, at 28% for both. Those with gout pursued medical care more often than did healthy controls (30% vs 7% in the prior year) and were more likely to have dyspnea (21% vs 14%) and urinary changes at presentation (15% vs 7%). Patients with gout had more comorbidities, and those with UCG had greater disease burden with more joint issues, pulmonary hypertension, and chronic pain, compared with patients whose gout was controlled. “In advanced CKD, gout is common and highly impactful with increased healthcare utilization and cardiovascular and bone/joint complication risk,” the study authors wrote. “Many gouty patients with CKD were not on ULT, but patients with UCG had higher health burden. Therefore, improved diagnosis/management of comorbid gout is needed for patients with advanced CKD.”
Effect of Serum Phosphate on Mortality in Patients on CRRT
Researchers evaluated the link between serum phosphate and mortality in critically ill patients needing continuous renal placement therapy (CRRT). “Phosphate derangements are common in critically ill patients and can potentially lead to respiratory failure, myocardial dysfunction, hemolysis, and impaired neuromuscular activity,” wrote Yeshwanter Radhakrishnan, MD, and colleagues. The team conducted a retrospective cohort study from December 2006 through November 2015 of critically ill patients receiving CRRT for acute kidney injury. Using logistic regression, they measured serum phosphate as markers for 90-day mortality in patients (N=1,108) prior to CRRT. Among participants, 55% died within 90 days following CRRT initiation. Prior to CRRT, 3%, 30%, and 66% of patients experienced hypophosphatemia, normophosphatemia, and hyperphosphatemia, respectively. Hypophosphatemia and hyperphosphatemia before CRRT were both strongly correlated with higher 90-day mortality, the researchers found.
Mindset & Clinical Outcomes Linked in Patients on Peritoneal Dialysis
A patient’s mindset specific to surviving on peritoneal dialysis (PD), especially during peritonitis incidents, may correlate with clinical outcomes. In a sample of adult patients on PD (N=101), Rachel Fissell, MD, MS, and colleagues examined the relationship between mindset and clinical outcomes at 1 year of follow-up. Patients completed the Health Mindset Scale (HMS) and risk models were adjusted for age, race, albumin, hypertension, and diabetes. At follow-up, the study team observed that 66% of patients remained on PD, 12% were on hemodialysis, 10% received a transplant, and 12% died. A higher HMS score implied lower mortality (HR, 0.87; 95% CI, 0.76-0.99) and receiving a transplant (HR, 1.33; 95% CI, 1.01-1.76). “Patients with a growth mindset may be more likely to navigate tasks needed to survive on PD, be listed, and then receive a transplant,” the study authors wrote. “Those with a more fixed mindset may not believe that their actions can change their clinical course, and so may be less likely to carry out healthy behaviors.
