What comorbidity should we adjust for in RRT patients? James Fotheringham School of Health and Related Research

What comorbidity should we adjust for in RRT patients?

James Fotheringham

School ofHealth andRelatedResearch

Outline

• What we knew about comorbidity before• How we gained additional data on comorbidity• Processing, specification & data completeness• Variation in comorbidity over age, race,

socioeconomic status and centre• What comorbid conditions need to be adjusted

for to compare survival• Other measures where comorbidity is important

Background

Fig. 6.17. The effect on survival after sequential adjustment for age, PRD and comorbidity, 2005–2009 cohort

Patterns and effects of missing comorbidity data for patients starting renal replacement therapy in England, Wales and Northern Ireland.Collier T, Steenkamp R, Tomson C, Caskey F, Ansell D, Roderick P, Nitsch D Nephrol Dial Transplant. 2011 Nov;26(11):3651-8. Epub 2011 Mar 24.

Significant Comorbidities

An improved comorbidity index for outcome analyses among dialysis patients.Liu J, Huang Z, Gilbertson DT, Foley RN, Collins AJ. Kidney Int. 2010 Jan;77(2):141-51. Epub 2009 Nov 11.

Chapter 4 Comorbidities and Current Smoking Status amongst Patients starting Renal Replacement Therapy in England, Wales and Northern Ireland from 2009 to 2010.Shaw C, Webb L, Casula A, Tomson CR. Nephron Clin Pract. 2012;120 Suppl 1:c81-91. Epub 2012 Sep 1.

UKRR’s limited ability to study this

2005 2006 2007 2008 2009 20100

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Renal Centre

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Overall Completeness for Comorbidity Centre-Specific Completeness for Comorbidity

21,633 Incident RRT Patients2002 – 2006

UKRR Data until Oct 2009

Coded location of death and death certificate contents

Covers all hospital deliveredcare in England

Diagnoses & Procedures

HES


Data processing

Date of first RRT

Acute myocardial infarction Cerebral vascular accident

Congestive heart failure Connective tissue disorder

Dementia Diabetes

Liver disease Peptic ulcer

Peripheral vascular disease Pulmonary disease

Cancer Diabetes complications

Paraplegia Metastatic cancer

Severe liver disease HIV

Acute myocardial infarction Cerebral vascular accident

Congestive heart failure Connective tissue disorder

Dementia Diabetes

Liver disease Peptic ulcer

Peripheral vascular disease Pulmonary disease

Cancer Diabetes complications

Paraplegia Metastatic cancer

Severe liver disease HIV

HES

I21 - Myocardial Infarction

E10 - Diabetes

L314 – Stent

Eth: Indian

SESR: 27524

HES

I71 - Peripheral Vasc. Dis.

I50 – Cong. Cardiac Failure

K40 – Coronary Art Bypass

Eth: Indian

SESR: 27524

Eth: missing

SESR: missing

Eth: Indian

SESR: 27524

Comorbidity Scoring Systems

Comorbidity measures for use with administrative data.Elixhauser A, Steiner C, Harris DR, Coffey RM.Med Care. 1998 Jan;36(1):8-27.

A new method of classifying prognostic comorbidity in longitudinal studies: development and validation.Charlson ME, Pompei P, Ales KL, MacKenzie CR. J Chronic Dis. 1987;40(5):373-83.

UK Renal Registry 14th Annual Report:Appendix B Definitions and Analysis Criteria

Influence of coexisting disease on survival on renal-replacement therapy.Khan IH, Catto GR, Edward N, Fleming LW, Henderson IS, MacLeod AM.Lancet. 1993 Feb 13;341(8842):415-8.

Quantifying comorbidity in peritoneal dialysis patients and its relationship to other predictors of survival.Davies SJ, Phillips L, Naish PF, Russell GI.Nephrol Dial Transplant. 2002 Jun;17(6):1085-92.

An improved comorbidity index for outcome analyses among dialysis patients.Liu J, Huang Z, Gilbertson DT, Foley RN, Collins AJ. Kidney Int. 2010 Jan;77(2):141-51. Epub 2009 Nov 11.

ICD10

ICD10

ICD10

Comorbid Conditions Prevalence (%)

Outliers (centres high/centres

low, out of 46)Hazard Ratio for Death (Multivariate) (95% CI)

Comorbidity Score

COPD 5.2 5 / 7 1.34 (1.23 - 1.47) 1

Arrhythmia 3.6 3 / 2 1.16 (1.04 - 1.3) 0

Heart Failure 14.9 4 / 5 1.39 (1.3 - 1.48) 1

CABG 4.9 5 / 4 0.81 (0.72 - 0.91) 0

Depression 2.4 1 / 1 1.55 (1.34 - 1.79) 2

Stroke 7.7 5 / 6 1.26 (1.16 - 1.36) 1

Myocardial Infarction 11.9 5 / 4 1.2 (1.11 - 1.29)

1

Lymphoma 3.4 2 / 1 3.48 (3.16 - 3.83) 3

Neurological Disease 3.8 3 / 3 1.52 (1.35 - 1.71)

2

Vascular Procedure 3.5 3 / 4 1.27 (1.13 - 1.42) 1

Valvular Heart Disease 3.7 5 / 5 1.3 (1.16 - 1.45)

1

Cancer 6.8 2 / 2 1.39 (1.28 - 1.51) 1

Connective Tissue Disease 3.4 3 / 1 1.34 (1.18 - 1.53)

1

Peptic Ulcer Disease 4.7 6 / 2 1.17 (1.06 - 1.29)

0

Claudication 7.1 7 / 6 1.19 (1.09 - 1.29) 0

Diabetes 31.6 7 / 5 1.44 (1.36 - 1.52) 1

Distribution of comorbidity score

0 1 2 3 4 5 6 7 8 90

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40

45

Comorbidity between patient groups

All Patients (18,798)

White(81.4%, 15,309)

Black(5.6%, 1,054)

South Asian(6.5%, 1,214)

Other (6.5%, 1,221)

Chi-Squared P value

Comorbidities

Diabetes 31.6 (5,944) 28.6 39.5 49.7 45.2 <0.001

Myocardial infarction 11.9 (2,229) 12.1 5.8 13.6 12.3 <0.001

CABG 4.9 (919) 4.7 1.8 8.2 7.3 <0.001

Heart Failure 14.9 (2,803) 14.7 14.5 16.8 15.4 0.251

Claudication 7.1 (1,344) 7.9 3.3 3.8 5 <0.001

Valvular Heart Disease 3.7 (697) 3.9 2.3 2.8 3.1 0.007

Stroke 7.7 (1,446) 7.7 7.5 7.9 7.2 0.904

COPD 5.2 (978) 5.8 0.9 3.3 3.8 <0.001

Comorbid Score (mean, 95% CI)

1.11 (1.09 - 1.13)

1.12 (1.1 - 1.14)

0.99 (0.91 - 1.07)

1.11 (1.05 - 1.17)

1.15(1.07 - 1.23)

1.15 (1.07 - 1.23)

Age and comorbidity

Chapter 13 the linkage of incident renal replacement therapy patients in England (2002-2006) to hospital episodes and national mortality data: improved demography and hospitalisation data in patients undergoing renal replacement therapy.

Fotheringham J, Fogarty D, Jacques R, El Nahas M, Campbell M. Nephron Clin Pract. 2012;120 Suppl 1:c247-60. Epub 2012 Sep 1.

Adjusted reporting

USRDS 2011ADR

All-cause standardized hospitalization & mortality ratios in small dialysis organizations, 2009Figure 10.20 (Volume 2)

January 1 point prevalent hemodialysis patients with Medicare as primary payor (SHRs); January 1 point prevalent hemodialysis patients (SMRS). SHRS & SMRS are calculated based on national hospitalization & death rates; adjusted for age, gender, race, & dialysis vintage.

Model performance

Variables Added AUCAge and Sex 0.721

1 - Specificity

1.00.80.60.40.20.0

Sen

siti

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1.0

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ROC Curve

Including centre 0.778All comorbidites 0.775Stroke 0.753Claudication 0.751COPD 0.750Myocardial Infarction 0.748Heart Failure 0.747Diabetes 0.739Year of Start 0.729Socioeconiomic Status 0.728Ethnicity 0.726

How to interpret the funnel plot

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Mean Centre 3yr Survival0.6991

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EthnicitySocioeconomic StatusYear of StartCOPDArrhythmiaHeart FailureCABGDepressionCerebrovascular DiseaseMyocardial InfarctionLymphomaNeurological DiseaseVascular ProcedureValvular Heart DiseaseCancerConnective Tissue DiseasePeptic Ulcer DiseaseClaudicationDiabetes

Why are there so few changes in outliers with additions of comorbidity?

Variation in comorbidity between centres

Renal Centre

Com

orbi

d Sc

ore

(95%

CI)

Variation in comorbidity between centres

Cent

re P

reva

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Cent

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udic

ation

Summary at this point

• Linked data can allow us to collect ethnicity and comorbidity data in 96.4% of patients

• A large proportion of variation was explained by age, ethnicity and socioeconomic status

• Comorbidity has a significant effect on individual survival

• Due to similar comorbidity prevalence across centres, comorbidity has a modest impact on centre specific outcomes

Other things to adjust for• Primary renal disease

• Late Referral– Eight centres changed how they coded specialities over timeframe– Speciality codes in remaining 38 could be used to identify first

renal contact

Model performance with primary renal disease and late referral

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910

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Age & Sex .722

Plus Late Referral .784

Plus Primary Renal Disease .782

Plus Comorbidity .777

Age, Sex, SES, Ethnicity, Year .731

1 - Specificity1.00.80.60.40.20.0

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Importance of comorbidity in other settings

• Admissions per year after starting RRTCondition Absent

Condition Present

Percent Increase

Age >70 1.89 3.07 62.4Modality Change 2.27 4 76.2Late Referral 2.16 2.4 11.1Diabetes 2.21 2.6 17.6Myocardial Infarct 2.3 2.62 13.9Heart Failure 2.25 2.74 21.8

No. of Comorbidities

Mean Transplant Length of Stay 95% CI

0 11.9 11.6 – 12.21 14.6 13.9 – 15.22 17.0 15.5 – 18.5>=3 20.8 17.3 – 24.3

• Length of stay at transplantation

Acknowledgements• UK Renal Registry

– All the statisticians & data staff– Charlie Tomson– David Ansell

• Research Capability Programme– Christian Newsome– Alan Barcroft

• ScHARR– Mike Campbell– Richard Jacques

• Kidney Research UK


Documents

What comorbidity should we adjust for in RRT patients? James Fotheringham School of Health and Related Research