Impact of renal surgery for cortical neoplasms on lipid metabolism

Objective: To examine the incidence of and risk factors for development of hyperlipidaemia in patients undergoing radical nephrectomy (RN) or partial nephrectomy (PN) for renal cortical neoplasms, as hyperlipidaemia is a major source of morbidity in chronic kidney disease (CKD).

Patients and methods: We conducted a two-centre retrospective analysis of 905 patients (mean age 57.5 years, mean follow-up 78 months), who underwent RN (n = 610) or PN (n = 295) between July 1987 and June 2007. Demographics, preoperative and postoperative hyperlipidaemia were recorded. De novo hyperlipidaemia was defined as that ocurring ≥6 months after surgery in cases where laboratory values met National Cholesterol Education Program Adult Treatment Panel III definitions. The Kaplan-Meier method was used to assess freedom from de novo hyperlipidaemia. Multivariable analysis was conducted to determine the risk factors for de novo hyperlipidaemia.

Results: There were no significant differences with respect to demographics, preoperative glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) (P = 0.123) and hyperlipidaemia (P = 0.144). Tumour size (cm) was significantly larger in the RN group vs the PN group (7.0 vs 3.7; P < 0.001). Significantly greater postoperative GFR <60 mL/min/1.73 m(2) was noted in the RN group (45.7 vs 18%, P < 0.001). Significantly, more de novo hyperlipidaemia developed in the RN group than in the PN group (23 vs 6.4%; P < 0.001). The mean time to development of hyperlipidaemia was longer for PN than for RN (54 vs 44 months; P = 0.03). Five-year freedom from de novo hyperlipidaemia probability was 76% for RN vs 96% for PN (P < 0.001). Multivariable analysis showed that RN (odds ratio [OR] 2.93; P = 0.0107), preoperative GFR <60 mL/min/1.73 m(2) (OR 1.98; P = 0.037) and postoperative GFR <60 mL/min/1.73 m(2) (OR 7.89; P < 0.001) were factors associated with hyperlipidaemia development.

Conclusion: Patients who underwent RN had a significantly higher incidence of and shorter time to development of de novo hyperlipidaemia. RN and pre- and postoperative eGFR <60 mL/min/1.73 m(2) were associated with development of hyperlipidaemia. Further follow-up and prospective investigation are necessary to confirm these findings.