Indian Journal of Urology
: 2012  |  Volume : 28  |  Issue : 2  |  Page : 241--242

Charlson comorbidity index: Does it accurately predict the morbidity and mortality after percutaneous nephrolithotomy?

Rohit Kathpalia 

Correspondence Address:
Rohit Kathpalia

How to cite this article:
Kathpalia R. Charlson comorbidity index: Does it accurately predict the morbidity and mortality after percutaneous nephrolithotomy?.Indian J Urol 2012;28:241-242

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Kathpalia R. Charlson comorbidity index: Does it accurately predict the morbidity and mortality after percutaneous nephrolithotomy?. Indian J Urol [serial online] 2012 [cited 2022 Jan 19 ];28:241-242
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Percutaneous nephrolithotomy (PCNL), first reported in 1976 by Fernstrom and Johannson, [1] is a valuable option for the management of renal stone disease. The modified Clavien system is used to grade the complications of PCNL, [2] however, no method is accepted to predict complications after PCNL. The ideal method must be a scoring system that is quick, simple, and reproducible and has a good correlation with the complication rates. The Charlson Comorbidity Index (CCI), which is a validated prospective method to classify comorbid conditions, has been shown to alter the risk of mortality in longitudinal studies for various diseases. [3] Authors carried out a retrospective study between September 2004 and March 2011 to evaluate whether CCI predicts the postoperative medical complications and death in patients who underwent PCNL. During this period 1406 PCNL procedures were performed. After complete patient evaluation and before subjecting them to surgery, all preexisting comorbidities were evaluated. The CCI score was calculated for each patient.

The CCI features 19 clinical conditions of which myocardial infarction, congestive heart failure, peripheral vascular disease, dementia, cerebrovascular disease, chronic pulmonary disease, connective tissue disease, ulcer disease, mild liver disease and mild diabetes without complications weighted a score of 1; hemiplegia, moderate to severe renal disease, diabetes with end organ damage, tumors, leukemia and lymphoma weighted 2; moderate or severe liver disease weighted 3 while metastatic solid tumor and AIDS weighted a score of 6, based on the severity of the condition. The CCI score was derived by adding the weighted scores for all comorbidities. On the basis of the distribution of the CCI score in this cohort, the patients were classified into three CCI score categories (0, 1, ≥2).

The score was calculated as "0" for 993 patients (70.6%, called Group I), as "1" for 316 patients (22.5%, called Group II), as "≥ 2" for 97 patients (6.9%, called Group III). Mean patient age was 39.9 ± 15.5 years (range 1-81) in Group I, 52.8 ± 12.6 years (range 1-77) in Group II and 58.6 ± 13.1 years (range 2-80) in Group III. Mean operative time was 63.8 ± 20.6 min in Group I, 65.1 ± 20.1 min in Group II, and 70.6 ± 23.7 min in Group III, which was statistically significant (P=.008).

The overall incidence of postoperative complications was 29.3% of which 24% were related directly to surgery and 5.3% were medical complications. The most common complication was hemorrhage necessitating blood transfusion in 133 cases (9.5%) that included 88 (8.9%) patients in Group I, 29 (9.2%) patients in Group II, and 16 (16.5%) patients in Group III (P=.049). Postoperative medical complications developed in 29 (2.9%) patients in Group I, 24 (7.6%) patients in Group II, and 21 (21.6%) patients in Group III (P= .001)

The authors concluded that patients with higher CCI score had a significantly greater rate of postoperative risk of hemorrhage and medical complications, including death, than those with lower CCI.


For large-volume stone disease, PCNL is the treatment of choice. Despite its effectiveness, serious complications such as blood loss, adjacent organ injuries, and life-threatening medical complications have been identified that occur at a reported rate of up to 83%. [4] To minimize complications, careful selection and preparation of the patient is essential. However, no method currently available has been accepted for predicting the complications of PCNL. The CCI is one of the most widely used comorbidity measures. It is easy to use and can be calculated in the office at the time the patient is making decisions regarding definitive treatment.

The present study is the first to report about the prediction of morbidity and mortality of PCNL using the CCI, demonstrating a direct relationship with preoperative comorbidity. Some of the past studies have suggested an increased postoperative bleeding in patients with diabetes mellitus, atherosclerosis, obesity, and hypertension because of associated arteriosclerosis with thickened basement membranes which makes such patients more prone to bleeding after the initial trauma of tract formation. [5]

Physicians should consider incorporating peri-operative comorbidity information to improve appropriate patient selection for PCNL. Although the study was limited by its retrospective design, the results seem to indicate that this could be a useful option to avoid surgery and its potential risks in the high-risk patient population.


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