Sickle Cell Nephropathy Linked to Increased Odds of All-Cause Mortality

Kunjan Udani, MD

New data suggests that patients with sickle cell nephropathy may have a higher odds of all-cause mortality. However, the study did not find an association between disease and major adverse cardiac events (MACE) and length of hospital stay.

Patients with sickle cell disease and chronic kidney disease may present with additional complications beyond their already established conditions. And yet, the complications and risks in this unique population have not be thoroughly characterized.

“Chronic kidney disease, in SCD [sickle cell disease], is associated with proteinuria, microalbuminuria, and hemoglobinuria,” the investigators wrote. “Cardiac complications in SCD include pulmonary hypertension, left ventricular diastolic heart disease, dysrhythmia, and sudden death.”

A team led by Kunjan Udani, MD, of Grand Strand Medical Center, SC, conducted a retrospective study of hospitalized patients who had previously been diagnosed with sickle cell disease and sickle cell nephropathy.

The team primarily sought to evaluate MACE, defined as nonfatal stroke, nonfatal myocardial infarction, and congestive heart failure (CHF) exacerbations, as well as all-cause mortality among this patient population.

The analysis, which utilized the HCA Healthcare Enterprise Data Warehouse, represented 186 hospitals across 21 states. All patients (n = 6693) were ≥18 years of age, majority were African American (90.2%) and female (65.1%).

Further, 9.8% had sickle cell nephropathy, 3.6% had MACE, 12.8% had asthma, 9.1% were diabetic, and 11% were tobacco users.

The average age of the overall population was 36.34 years, while the average age for those with MACE and congestive heart failure was 52.83 and 52.46 years, respectively.”

The average length of stay for patients with sickle cell nephropathy was 4.76 days—compared with 2.52 days for sickle cell patients without nephropathy. As such, according to multivariate linear regression, sickle cell nephropathy was linked to a 0.371 longer stay versus those without nephropathy, a finding that the investigators did not consider to be statistically significant.

Nevertheless, patients with sickle cell nephropathy had a significantly higher mortality (odds ratio [OR], 2.343; 95% CI, 1.063-5.166; P = .035) compared with non-nephropathy sickle cell patients.

Additionally, nephropathy patients trended towards a higher risk for congestive heart failure exacerbations (OR, 1.438; 95% CI, 0.923-2.241; P = .109). But there were no significant differences in MACE events (OR 1.281; 95% CI, 0.828-1.982; P = .265) or length of stay (95% CI; -0.157-0.899; P = .169) between the groups.

Udani and colleagues acknowledged potential limitations, including reliance on ICD-10 codes and the retrospective nature of the study.

“While sickle cell nephropathy may be associated with all-cause mortality,” they wrote, “further studies are warranted to understand the association between sickle cell nephropathy and cardiovascular complications.”

The study, “All-Cause Mortality and Incidence of Major Adverse Cardiac Events in Sickle Cell Nephropathy: A Comparative Study,” was published online in Cureus.