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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

Distribution of outcomes stratified by Comorbidity Index Score groups
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Fig3: Distribution of outcomes stratified by Comorbidity Index Score groups

Mentions: Over 1796.6 patient years at risk, there were 311 deaths. The distribution of deaths stratified by CCI and ESRD-CI scores are graphically displayed in Fig. 3. There was a rise in the number of deaths and fall in the number of patients that received a kidney transplant with each ESRD-CI score cut-off. In an unadjusted Cox survival analysis, relative to patients with an ESRD-CI score of ≤1, those with scores of ≥6 had a mortality HR of 2.64 (95 % CI 1.91 to 3.65, p < 0.001, Table 3). A similar mortality HR was observed for patients with CCI scores of ≥6 compared to 2 (HR 2.91, 95 % CI 2.04 to 4.15, p < 0.001). After multivariable adjustment, there was attenuation in the HR. Similar HR’s were noted for patients with scores of 4–6 for the ESRD-CI. For the CCI, there was separation in the HR’s for scores of 4–6 however, confidence intervals overlapped (Table 3).Fig. 3


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)

Distribution of outcomes stratified by Comorbidity Index Score groups
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig3: Distribution of outcomes stratified by Comorbidity Index Score groups
Mentions: Over 1796.6 patient years at risk, there were 311 deaths. The distribution of deaths stratified by CCI and ESRD-CI scores are graphically displayed in Fig. 3. There was a rise in the number of deaths and fall in the number of patients that received a kidney transplant with each ESRD-CI score cut-off. In an unadjusted Cox survival analysis, relative to patients with an ESRD-CI score of ≤1, those with scores of ≥6 had a mortality HR of 2.64 (95 % CI 1.91 to 3.65, p < 0.001, Table 3). A similar mortality HR was observed for patients with CCI scores of ≥6 compared to 2 (HR 2.91, 95 % CI 2.04 to 4.15, p < 0.001). After multivariable adjustment, there was attenuation in the HR. Similar HR’s were noted for patients with scores of 4–6 for the ESRD-CI. For the CCI, there was separation in the HR’s for scores of 4–6 however, confidence intervals overlapped (Table 3).Fig. 3

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