Charlson Comorbidity Scoring System

Estimating Prognosis for Dialysis Patients

programmed by Stephen Z. Fadem, M.D., FACP, FASN

Ageyrs    Serum Albuming/dL

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One Point

Two Points

Three Points

Six Points

Charlson Comorbidity Index (CCI) ____.

SURVIVAL1 YEAR2 YEAR
Survival based on CCI __ __
Survival based on Serum Albumin__ __
Survival based upon both serum alb and CCI __ __

Prognosis for ESRD patients can be estimated using the Charlson Comorbidity Index (CCI), shown in Table 1 and below, and the serum albumin. Based on the medical literature referencedbelow, the CCI is a good prognostic tool for ESRD patients, and is easier to use in the non-research setting than the Index of Coexistent Diseases. CCI scores were calculated in 1761 individuals who participated in a comorbidity assessment project 8 conducted between 1998-2001 in 41 dialysis units from Dialysis Clinic Inc. (DCI), a non-for profit dialysis" provider. All were hemodialysis patients with similar demographic characteristics as contemporary USRDS populations: the mean age was 62 (SD 15); 28% were African American; 52% were male; and 44% had diabetes as the cause of ESRD. Forty eight percent were incident to dialysis, meaning that they had started dialysis less than a year prior to the time of the comorbidity assessment. The prognostic calculator (see Table 2 is based on observation of this study population and provides estimates of one and two year survival probabilities across subgroups defined by CCI Level and serum albumin. The 95% confidence intervals have been included to aid in interpretation of the data.

In the systematic literature review conducted by the RPA-ASN workgroup that developed the second clinical practice guideline (CPG), Shared Decision-Making in the Appropriate Initiation of and Withdrawal from Dialysis, serum albumin was found to be an independent predictor of mortality. The bromcresol green assay with normal range of 3.5 to 5.0 g/dL was used to measure serum albumin.*

Nephrologists should use the estimate of survival obtained from this calculator according to the recommendations of appropriate clinical practice guidelines, i.e.Shared Decision-Making in the Appropriate Initiation of and Withdrawal from Dialysis. This guideline recommends shared decision-making between the physician and the patient (or if the patient lacks decision-making capacity, the patient’s legal representative). The estimate of survival should be used only to assist in promoting informed""consent in deciding whether to commence or stop dialysis. Patient and family""education about prognosis should always consider the patient's preferences. Not all patients may want to be informed of their prognosis. Instead, some patients may prefer that a family member or friend be informed of their prognosis and participate in dialysis decision-making. Like other information to be disclosed in the process of obtaining informed consent or refusal, an estimate of prognosis needs to be provided in a culturally sensitive manner. In addition, prognosis alone may not be a sufficient reason for some patients and families to refuse dialysis, particularly when dialysis may allow the achievement of certain goals. Patients and families may choose to commence dialysis regardless of the estimate of survival obtained from this calculator or any recommendation from their nephrologist. The ultimate decision as to whether to commence or stop dialysis should be shared between the patient (or his/her legal representative) and the treating nephrologist.

The authors and owners of this program make no warranties or representations with respect to the application of this calculator in individual cases. Any recommendations made by a nephrologist based upon the information obtained from this calculator are the sole responsibility of the user.

*Nephrologists will need to enter the lower limit of albumin (LLA) if it is less than 3.5 g/dL. This program will autoadjust the patient’s serum albumin level for the normal range for the serum albumin assay based upon the LLA entered. For example, if a patient’s serum albumin level is 3.3 g/dL and the lower limit of normal (LLA) on the assay used to measure the patient's blood is 3.2g/dL, the serum albumin level will be adjusted up (i.e. normalized). The program will multiply the level by a correction factor of 3.5/LLA. For instance, if the LLA is 3.2, this would be 1.094.

This calculator defaults to an LLA of 3.5 g/dL or a correction factor of 1. If different, please correct in the box provided: LLA g/dL.

The conversion factor will be conversion_factor.


Table 2
One and Two-Year Survival Probabilities** Across Charlson Comorbidity Index Levels
Albumin ≤ 3.5g/dL
CCI Level n Frequency* Probability of 1 yr survival 95% confidence interval Probability of 2 yr survival confidence interval
2-3 34 2% 0.91 (0.81-1.00) 0.87 (0.77-0.99)
4-5 97 6% 0.73 (0.64-0.82) 0.61 (0.49-0.73)
6-7 173 10% 0.69 (0.62-0.77) 0.49 (0.41-0.59)
>8 138 8% 0.52 (0.43-0.61) 0.30 (0.20-0.40)
Albumin ≥ 3.5g/dL CCI
CCI Level n Frequency* Probability of 1 yr survival 95% confidence interval Probability of 2 yr survival confidence interval
2-3 230 13% 0.93 (0.90-0.96) 0.89 (0.84-0.93)
4-5 299 17% 0.89 (0.85-0.92) 0.75 (0.69-0.80)
6-7 488 28% 0.84 (0.80-0.87) 0.67 (0.63-0.72)
>8 302 17% 0.75 (0.70-0.80) 0.52 (0.45-0.58)

*Frequency of subjects within groups divided by CCI Leveland serum albumin

** Survival probabilityestimates are based on observation of 1761 incident and prevalent hemodialysis patients from 41 dialysis facilities of Dialysis Clinic Inc.[8] See text for details.

References

  1. Beddhu S, Bruns FJ, Saul M, Seddon P, Zeidel ML: A Simple Comorbidity Scale Predicts Clinical Outcomes and Costs in Dialysis Patients. The American Journal of Medicine 108:609-613, 2000
  2. Charlson ME, Pompei P, Ales KL, MacKenzie CR: A New Method of Classifying Prognostic Comorbidity in Longitudinal Studies: Development and Validation. Journal of Chronic Diseases 40:373-383, 1987
  3. Fried L, Bernardini J, Piraino B: Charlson Comorbidity Index as a Predictor of Outcomes in Incident Peritoneal Dialysis Patients. American Journal of Kidney Diseases 37:337-342, 2001
  4. Hemmelgarn BR, Manns BJ, Quan H, Ghali WA: Adapting the Charlson Comorbidity Index for Use in Patients with ESRD. American Journal of Kidney Diseases 42:125-132, 2003
  5. Van Manen JG, Korevaar JC, Dekker FW, Boeschoten EW, Bossuyt PMM, Krediet RT: Adjustment for Comorbidity in Studies on Health Status in ESRD Patients: Which Comorbidity Index to Use? Journal of the American Society of Nephrology 14:478-485, 2003
  6. Van Manen JG, Korevaar JC, Dekker FW, Boeschoten EW, Bossuyt PMM, Krediet RT: How to Adjust for Comorbidity in Survival Studies in ESRD Patients: A Comparison of Different Indices. American Journal of Kidney Diseases 40:82-89, 2002
  7. Fried L, Bernardini J, Piraino B: Comparison of the Charlson Comorbidity Index and the Davies Score as a predictor of outcomes in PD patients. Perit Dial Int 23:568-573, 2003
  8. Miskulin, D., Martin, A., Brown, R., Fink, N., Coresh, J., Powe, N., Zager, P., Meyer, K. and Levey, A., Predicting One-Year Mortality in an Outpatient Hemodialysis Population:" A Comparison of Comorbidity Instruments. Nephrol Dial Transplant, 19:413-20,2004.