Renal function decreases with aging and is also close- ly related to chronic diseases that lead to poor perioper- ative outcomes, such as diabetes mellitus, dyslipidemia and hypertension. Chronic kidney disease (CKD) is de- fined as the estimated GFR<60cc /min/1.73m2 and has been associated with an increase in all-cause deaths and especially cardiovascular deaths (10). Chronic kidney disease (CKD) significantly increases the risk of death, cardiovascular disease and hospitalization of adult pa- tients (11).In our study, no deaths were reported.Dura- tion of hospital stay was higher in group-3 compared to other groups but there was no statistical difference be- tween the groups. We attribute the longer hospital stay in this group-3 to our desire to follow up more stringent GFR.
Various serious complications may occur in patients with impaired renal function, such as disruption of drug metabolism and excretion, edema in tissues as a result of impaired water-electrolyte balance, delay in wound healing and difficulties in infection control (12,13). It has also been reported that immune deficiency is com- mon in patients with CKD (14).In our study, the num- ber of patients who developed postoperative infection was similar between the groups. Antibiotic therapy was sufficient to control the infection in these patients.
Sairam et al. (15) found that there was a signifi- cant difference between the total complication rates in their articles comparing patients with CKD 0-2 and 4-5. (18.5% vs. 33.8%) p<0.001.In the article by Kilinc et al. (16) comparing the diagnostic RIRS (Retrograde intrarenal surgery) results of patients with chronic he- modialysis patients and normal kidney function; while there was no statistically significant difference between the overall complication rates (10.5% vs. 4.8%; p=0.16). In our study, complications were classified according to the Clavien-Dindo classification system. We found no statistical significiant difference between the complica- tion rates of both total and subgroups.
Seitz et al. (17) reported there were 7% blood trans- fusion requirement in patients with normal kidney function during PCNL operation. In a review, Jones et al. (18) investigated the efficacy and safety of PCNL in CKD patients, the need for transfusion was 20%. This rate increase was associated with high preoperative anemia prevalence and presence of platelet dysfunction in CKD patients.In the CROES study, when they com- pared the transfusion requirement ratio in patients with Level 4/5 to those with Level 3 CKD, they found 18.4% and 6.1%, respectively. They also found statistically sig- nificant difference among these ratios (p<0.001) (19). In our study, we evaluated the mean amount of bleed- ing, not the transfusion rate, because the preoperative hemogram values of all patients were not at the same rate. We found no statistical significiant difference be- tween the groups when the amounts of bleeding were compared.
In the CROES study, the stone-free rates were 71.2% in patients with stage 4-5 CKD and 76.9% in patients with stage 0-2 CKD (15). Yuruk et al. (20) compared the patients with CKD stage 4-5 and patients with normal kidney function with RIRS due to kidney stones. The third month stone-free rates were 87.1% and 86.2%, respectively (p=0.75).Srivastava et al. (221) investigat- ed SWL results in patients with GFR <30 ml / min and reported that retreatment requirement was 84.4% and stone-free rates were 34.4%. In our study, stone-free rates were similar among the groups (p=0.542).Stone- free rates in our study were also similar to other studies (74.6-76.2%), and there was no statistically significant difference between the groups.
The main limitations of the current study are its ret- rospective design which could possibly cause some bias, and using serum creatinin evalueto calculate GFR may not be the best method. TheCockcroft–Gault formula is a widely used and shows GFR changes with appropriate error.However, the aim of our study was not to define the most accurate GFR measurement. We use GFR only for preoperative classification. So, we think that the Cockcroft–Gaultformula will not cause significant er- rors in terms of the results. Our study has some poten- tial advantages. Firstly, the same surgeons performed PCNL in our clinic with the same protocol so there was no surgery-effect bias.
DISCUSSION
Renal function decreases with aging and is also close- ly related to chronic diseases that lead to poor perioper- ative outcomes, such as diabetes mellitus, dyslipidemia and hypertension. Chronic kidney disease (CKD) is de- fined as the estimated GFR<60cc /min/1.73m2 and has been associated with an increase in all-cause deaths and especially cardiovascular deaths (10). Chronic kidney disease (CKD) significantly increases the risk of death, cardiovascular disease and hospitalization of adult pa- tients (11).In our study, no deaths were reported.Dura- tion of hospital stay was higher in group-3 compared to other groups but there was no statistical difference be- tween the groups. We attribute the longer hospital stay in this group-3 to our desire to follow up more stringent GFR.
Various serious complications may occur in patients with impaired renal function, such as disruption of drug metabolism and excretion, edema in tissues as a result of impaired water-electrolyte balance, delay in wound healing and difficulties in infection control (12,13). It has also been reported that immune deficiency is com- mon in patients with CKD (14).In our study, the num- ber of patients who developed postoperative infection was similar between the groups. Antibiotic therapy was sufficient to control the infection in these patients.
Sairam et al. (15) found that there was a signifi- cant difference between the total complication rates in their articles comparing patients with CKD 0-2 and 4-5. (18.5% vs. 33.8%) p<0.001.In the article by Kilinc et al. (16) comparing the diagnostic RIRS (Retrograde intrarenal surgery) results of patients with chronic he- modialysis patients and normal kidney function; while there was no statistically significant difference between the overall complication rates (10.5% vs. 4.8%; p=0.16). In our study, complications were classified according to the Clavien-Dindo classification system. We found no statistical significiant difference between the complica- tion rates of both total and subgroups.
Seitz et al. (17) reported there were 7% blood trans- fusion requirement in patients with normal kidney function during PCNL operation. In a review, Jones et al. (18) investigated the efficacy and safety of PCNL in CKD patients, the need for transfusion was 20%. This rate increase was associated with high preoperative anemia prevalence and presence of platelet dysfunction in CKD patients.In the CROES study, when they com- pared the transfusion requirement ratio in patients with Level 4/5 to those with Level 3 CKD, they found 18.4% and 6.1%, respectively. They also found statistically sig- nificant difference among these ratios (p<0.001) (19). In our study, we evaluated the mean amount of bleed- ing, not the transfusion rate, because the preoperative hemogram values of all patients were not at the same rate. We found no statistical significiant difference be- tween the groups when the amounts of bleeding were compared.
In the CROES study, the stone-free rates were 71.2% in patients with stage 4-5 CKD and 76.9% in patients with stage 0-2 CKD (15). Yuruk et al. (20) compared the patients with CKD stage 4-5 and patients with normal kidney function with RIRS due to kidney stones. The third month stone-free rates were 87.1% and 86.2%, respectively (p=0.75).Srivastava et al. (221) investigat- ed SWL results in patients with GFR <30 ml / min and reported that retreatment requirement was 84.4% and stone-free rates were 34.4%. In our study, stone-free rates were similar among the groups (p=0.542).Stone- free rates in our study were also similar to other studies (74.6-76.2%), and there was no statistically significant difference between the groups.
The main limitations of the current study are its ret- rospective design which could possibly cause some bias, and using serum creatinin evalueto calculate GFR may not be the best method. TheCockcroft–Gault formula is a widely used and shows GFR changes with appropriate error.However, the aim of our study was not to define the most accurate GFR measurement. We use GFR only for preoperative classification. So, we think that the Cockcroft–Gaultformula will not cause significant er- rors in terms of the results. Our study has some poten- tial advantages. Firstly, the same surgeons performed PCNL in our clinic with the same protocol so there was no surgery-effect bias.