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Comorbidity burden at dialysis initiation and mortality: A cohort study.

Gomez AT, Kiberd BA, Royston JP, Alfaadhel T, Soroka SD, Hemmelgarn BR, Tennankore KK - Can J Kidney Health Dis (2015)

Bottom Line: A high level of comorbidity at dialysis initiation is associated with an increased risk of death.ESRD-CI scores of 4, 5 and ≥6 were associated with a similar mortality risk (adjusted relative hazard of 1.95, 1.89 and 1.99, respectively).Abstract available from the publisher.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Medicine, Dalhousie University, Halifax, NS Canada.

ABSTRACT

Background: A high level of comorbidity at dialysis initiation is associated with an increased risk of death. However, contemporary assessments of the validity and prognostic value of comorbidity indices are lacking.

Objectives: To assess the validity of two comorbidity indices and to determine if a high degree of comorbidity is associated with mortality among dialysis patients.

Design: Cohort study.

Setting: QEII Health Sciences Centre (Halifax, Nova Scotia, Canada).

Patients: Incident, chronic dialysis patients between 01 Jan 2006 and 01 Jul 2013.

Exposure: The Charlson Comorbidity Index (CCI) and End-Stage Renal Disease Comorbidity Index (ESRD-CI) were used to classify individual comorbid conditions into an overall score. Comorbidities were classified using patient charts and electronic records.

Outcome: All-cause mortality. Confounders: Patient demographics, dialysis access, cause of ESRD and baseline laboratory data.

Methods: Regression coefficients were estimated on the CCI and ESRD-CI. Discrimination for death was assessed using Harrell's c-index. Adjusted Cox proportional hazard models were used to calculate relative hazards and 95 % confidence intervals for each category of the CCI and ESRD-CI.

Results: The cohort consisted of 771 ESRD patients from 01 Jan 2006 to 01 Jul 2013. Most were male (62 %) and Caucasian (91 %). The cohort had a high proportion of diabetes (48 %), history of previous myocardial infarction (31 %) and heart failure (22 %). Regression coefficients on the CCI and ESRD-CI were 0.55 and 0.52, respectively. The c-index, for the prediction of death, was 0.61 for the CCI and 0.63 for the ESRD-CI. ESRD-CI scores of 4, 5 and ≥6 were associated with a similar mortality risk (adjusted relative hazard of 1.95, 1.89 and 1.99, respectively). There was a small increased mortality risk for CCI scores of 4, 5 and ≥6 (adjusted relative hazard of 1.86, 2.38 and 2.71, respectively).

Limitations: Classification of comorbidities for each patient was determined by clinical impression.

Conclusions: The CCI and ESRD-CI have a limited ability to discriminate mortality risk for incident dialysis patients. Acknowledging the frequency with which they are used, this study emphasizes the need to re-examine the usefulness of previously derived comorbidity indices in contemporary dialysis cohorts.

No MeSH data available.


Related in: MedlinePlus

Kaplan-Meier survival curves for time to death stratified by CCI Score groups
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Fig2: Kaplan-Meier survival curves for time to death stratified by CCI Score groups

Mentions: Cox regression on the precise CCI and ESRD-CI revealed coefficients of 0.55 (SE 0.08) and 0.52 (SE 0.07), respectively (Table 2). Cox regression on the categorical CCI and ESRD-CI revealed similar coefficients (0.56 and 0.52, respectively). The c-index was 0.61 (SE 0.02) for both the precise and categorical CCI, and 0.63 (SE 0.02) and 0.62 (SE 0.02) for the precise and categorical ESRD-CI (Table 2). Kaplan-Meier survival curves for each ESRD-CI score cut-off are displayed in Fig. 1 (Log-rank P < 0.001). There was separation of the curves for patients with a high versus low score (6+ versus 0/1 or 2). However, discordance was observed for patients with an intermediate score. A similar finding was noted for the CCI, however, there was slightly more separation between the curves in an incremental fashion based on score (Fig. 2).Table 2


Comorbidity burden at dialysis initiation and mortality: A cohort study.

Gomez AT, Kiberd BA, Royston JP, Alfaadhel T, Soroka SD, Hemmelgarn BR, Tennankore KK - Can J Kidney Health Dis (2015)

Kaplan-Meier survival curves for time to death stratified by CCI Score groups
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4562341&req=5

Fig2: Kaplan-Meier survival curves for time to death stratified by CCI Score groups
Mentions: Cox regression on the precise CCI and ESRD-CI revealed coefficients of 0.55 (SE 0.08) and 0.52 (SE 0.07), respectively (Table 2). Cox regression on the categorical CCI and ESRD-CI revealed similar coefficients (0.56 and 0.52, respectively). The c-index was 0.61 (SE 0.02) for both the precise and categorical CCI, and 0.63 (SE 0.02) and 0.62 (SE 0.02) for the precise and categorical ESRD-CI (Table 2). Kaplan-Meier survival curves for each ESRD-CI score cut-off are displayed in Fig. 1 (Log-rank P < 0.001). There was separation of the curves for patients with a high versus low score (6+ versus 0/1 or 2). However, discordance was observed for patients with an intermediate score. A similar finding was noted for the CCI, however, there was slightly more separation between the curves in an incremental fashion based on score (Fig. 2).Table 2

Bottom Line: A high level of comorbidity at dialysis initiation is associated with an increased risk of death.ESRD-CI scores of 4, 5 and ≥6 were associated with a similar mortality risk (adjusted relative hazard of 1.95, 1.89 and 1.99, respectively).Abstract available from the publisher.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Medicine, Dalhousie University, Halifax, NS Canada.

ABSTRACT

Background: A high level of comorbidity at dialysis initiation is associated with an increased risk of death. However, contemporary assessments of the validity and prognostic value of comorbidity indices are lacking.

Objectives: To assess the validity of two comorbidity indices and to determine if a high degree of comorbidity is associated with mortality among dialysis patients.

Design: Cohort study.

Setting: QEII Health Sciences Centre (Halifax, Nova Scotia, Canada).

Patients: Incident, chronic dialysis patients between 01 Jan 2006 and 01 Jul 2013.

Exposure: The Charlson Comorbidity Index (CCI) and End-Stage Renal Disease Comorbidity Index (ESRD-CI) were used to classify individual comorbid conditions into an overall score. Comorbidities were classified using patient charts and electronic records.

Outcome: All-cause mortality. Confounders: Patient demographics, dialysis access, cause of ESRD and baseline laboratory data.

Methods: Regression coefficients were estimated on the CCI and ESRD-CI. Discrimination for death was assessed using Harrell's c-index. Adjusted Cox proportional hazard models were used to calculate relative hazards and 95 % confidence intervals for each category of the CCI and ESRD-CI.

Results: The cohort consisted of 771 ESRD patients from 01 Jan 2006 to 01 Jul 2013. Most were male (62 %) and Caucasian (91 %). The cohort had a high proportion of diabetes (48 %), history of previous myocardial infarction (31 %) and heart failure (22 %). Regression coefficients on the CCI and ESRD-CI were 0.55 and 0.52, respectively. The c-index, for the prediction of death, was 0.61 for the CCI and 0.63 for the ESRD-CI. ESRD-CI scores of 4, 5 and ≥6 were associated with a similar mortality risk (adjusted relative hazard of 1.95, 1.89 and 1.99, respectively). There was a small increased mortality risk for CCI scores of 4, 5 and ≥6 (adjusted relative hazard of 1.86, 2.38 and 2.71, respectively).

Limitations: Classification of comorbidities for each patient was determined by clinical impression.

Conclusions: The CCI and ESRD-CI have a limited ability to discriminate mortality risk for incident dialysis patients. Acknowledging the frequency with which they are used, this study emphasizes the need to re-examine the usefulness of previously derived comorbidity indices in contemporary dialysis cohorts.

No MeSH data available.


Related in: MedlinePlus