Renal functional decline after radical nephrectomy strongly associated with age

A retrospective analysis showed that age is a significant risk factor for renal functional decline following radical nephrectomy, indicating that nephron sparing management should be prioritized in elderly patients when it is safe and feasible.¹

The study researchers, led by Mimi Vu Nguyen, a medical student at the UC San Diego School of Medicine, conducted the analysis because prior research had not definitively made clear the specific individual impact of age on functional decline after radical nephrectomy.

In a poster shared during the Society of Urologic Oncology 2023 Annual Meeting, Nguyen et al described how statistical modeling using multivariable logistic regression revealed that compared with patients aged ≤50 years, patients aged 50-70 years (HR, 3.35; P <.001), and patients aged >70 years (HR 7.7; P <.001) had a much greater risk of developing de novo CKD stage 3b chronic kidney disease (CKD) following radical nephrectomy.

Increasing age was also linked to a higher risk of developing de novo CKD Stage 3a for both the 50-to-70-years group (HR, 3.4; P <.001) and the >70-years group (HR, 9.4; P <.001). Patients aged >70 years also had an increased risk of developing CKD stage 4 disease (HR, 1.96; P = .027).

Additional research using Kaplan-Meier analysis showed aged-associated declines in 5-year rates of freedom from CKD stage 3a (≤50 years, 73.9%; 50-70 years, 53.7%; and >70 years, 37.06%; P <.001), CKD Stage 3b (≤50 years, 92.7%; 50-70 years, 71.8%; and >70 years, 55.5%; P <.001), and CKD Stage 4 (≤50 years, 93.7%; 50-70 years, 89.8%; and >70 years, 81.2%; P <.001) disease.

Linear-regression analysis also showed that increasing age was significantly correlated with increased delta eGFR (estimated glomerular filtration rate; β = -0.212; P <.001).

“We showed that in the oldest patient cohorts, age became an independent risk factor for development of de novo CKD after surgical intervention in patients who underwent radical nephrectomy. We also did a linear regression analysis that showed age as being the only independent risk factor for increasing delta eGFR after surgery,” Nguyen explained in an interview with Urology Times at the SUO meeting.

“And so taken together, our findings really suggested in elderly patients with complex renal masses that the recommendation may be to consider less aggressive forms of management, including active surveillance, cryoablation, or partial nephrectomy when it’s safe and feasible, given the increased risk of rapid renal function decline in these older patient cohorts,” added Nguyen.

The retrospective review included patients from the International Marker Consortium for Renal Cancer (INMARC) registry who underwent radical nephrectomy. Overall, there were 2436 patients: 513 patients aged ≤50 years; 1344 patients aged 50-70 years; and 579 patients aged >70 years. Patient demographics and characteristics regarding sex, race/ethnicity, baseline BMI, and baseline tumor size were well balanced among the 3 age categories.

The primary end point of the study was the development of de novo CKD Stage 3b (eGFR <45 mL/min/1.73m2). Secondary end points included de novo CKD Stage 3a (eGFR <60) and de novo Stage CKD 4 (eGFR <30).

Of note, the researchers also found that increasing BMI (HR, 1.03; P = .002), coronary artery disease (CAD; HR, 1.70; P = .01), and type 2 diabetes (HR, 1.40; P = .03) were also independent risk factors for de novo CKD stage 3b disease. Increasing BMI (HR, 1.03; P = .002) and CAD (HR, 1.9; P = .015) were also risk factors for de novo CKD stage 3a disease.

Regarding next steps, Nguyen said, “We’re looking into more granular data to differentiate between the different continuous age groups and potentially determine what could be a specific age threshold we could recommend that would be best to pursue less aggressive forms of management.”

Reference

1. Nguyen MV, Walia A, Saidian A, et al. Impact of Age on Functional Decline Following Radical Nephrectomy: Analysis of the International Marker Consortium for Renal Cancer (INMARC). Presented at: Society of Urologic Oncology 23rd Annual Meeting; November 30-December 2; San Diego, California. Abstract 141.