The impact of metabolic syndrome on long-term outcomes of percutaneous nephrolithotomy (PCNL)

Abstract

Study Type--Prognosis (cohort) Level of Evidence 2b. What's known on the subject? and What does the study add? The presence of metabolic syndrome is associated with development of kidney stones and an increase in the stone-recurrence rate. However, studies reporting long-term results of percutaneous nephrolithotomy (PCNL) in metabolic syndrome are lacking. The present study showed that metabolic syndrome was associated with worsening renal function at long-term follow-up and the stone-recurrence rate recurrence after PCNL in patients with metabolic syndrome was 3.2-fold higher compared with the control group.

Objective: • To investigate the impact of metabolic syndrome on long-term kidney function and stone recurrence rates after percutaneous nephrolithotomy (PCNL).

Patients and methods: • In all, 73 patients with metabolic syndrome who underwent stone analysis and had a minimum follow-up of 12 months after PCNL were reviewed. • In addition, 73 patients without any metabolic syndrome components who had undergone PCNL and were followed-up for at least 12 months were included in the study as the control group. • These control group patients were selected from 226 patients who were matched with the patients with metabolic syndrome using a 1 : 1 ratio. The matching parameters were age, gender and stone size.

Results: • Stone analyses showed that calcium oxalate monohydrate (52.0%) and uric acid (21.9%) were most common among patients with metabolic syndrome, whereas calcium oxalate monohydrate (76.7%) was the most common stone type in the control group. • Stone recurrences occurred with a mean (sd, range) of 36.1 (21.3, 12-109) months follow-up in 26 patients (41.9%) and 12 patients (18.9%) in the metabolic syndrome and control groups, respectively (P = 0.003). • While estimated glomerular filtration rate was decreased from 87.8 to 66.6 mL/min/1.73 m(2) in the metabolic syndrome group, it changed from 96.4 to 91.2 mL/min/1.73 m(2) in control group at long-term follow-up.

Conclusions: • The most frequent stone type was calcium oxalate monohydrate in patients with or without metabolic syndrome. • In patients with metabolic syndrome who underwent PCNL, the stone recurrence rate was >40%. • Metabolic syndrome is associated with worsening renal function at long-term follow-up.