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

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 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 Nov;26(11): 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 Jan;77(2): 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 Shaw C, Webb L, Casula A, Tomson CR. Nephron Clin Pract. 2012;120 Suppl 1:c Epub 2012 Sep 1.

UKRR’s limited ability to study this Overall Completeness for Comorbidity Centre-Specific Completeness for Comorbidity

21,633 Incident RRT Patients 2002 – 2006 UKRR Data until Oct 2009 Coded location of death and death certificate contents Covers all hospital delivered care in England Diagnoses & Procedures HES School of Health and Related Research

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: HES I71 - Peripheral Vasc. Dis. I50 – Cong. Cardiac Failure K40 – Coronary Art Bypass Eth: Indian SESR: 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 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): 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 Feb 13;341(8842): 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 Jun;17(6): An improved comorbidity index for outcome analyses among dialysis patients. Liu J, Huang Z, Gilbertson DT, Foley RN, Collins AJ. Kidney Int Jan;77(2): Epub 2009 Nov 11.  ICD10

Comorbid Conditions Prevalence (%) Outliers (centres high/centres low, out of 46) Hazard Ratio for Death (Multivariate) (95% CI) Comorbidity Score COPD 5.25 / ( ) 1 Arrhythmia 3.63 / ( ) 0 Heart Failure / ( ) 1 CABG 4.95 / ( ) 0 Depression 2.41 / ( ) 2 Stroke 7.75 / ( ) 1 Myocardial Infarction / 41.2 ( ) 1 Lymphoma 3.42 / ( ) 3 Neurological Disease 3.83 / ( ) 2 Vascular Procedure 3.53 / ( ) 1 Valvular Heart Disease 3.75 / 51.3 ( ) 1 Cancer 6.82 / ( ) 1 Connective Tissue Disease 3.43 / ( ) 1 Peptic Ulcer Disease 4.76 / ( ) 0 Claudication 7.17 / ( ) 0 Diabetes / ( ) 1

Distribution of comorbidity score

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 Diabetes31.6 (5,944) <0.001 Myocardial infarction11.9 (2,229) <0.001 CABG4.9 (919) <0.001 Heart Failure14.9 (2,803) Claudication7.1 (1,344) <0.001 Valvular Heart Disease3.7 (697) Stroke7.7 (1,446) COPD5.2 (978) <0.001 Comorbid Score (mean, 95% CI) 1.11 ( ) 1.12 ( ) 0.99 ( ) 1.11 ( ) 1.15 ( ) 1.15 ( )

Age and comorbidity Chapter 13 the linkage of incident renal replacement therapy patients in England ( ) 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:c Epub 2012 Sep 1.

Adjusted reporting

USRDS 2011ADR All-cause standardized hospitalization & mortality ratios in small dialysis organizations, 2009 Figure (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 AddedAUC Age and Sex Specificity Sensitivity ROC Curve Including centre0.778 All comorbidites0.775 Stroke0.753 Claudication0.751 COPD0.750 Myocardial Infarction0.748 Heart Failure0.747 Diabetes0.739 Year of Start0.729 Socioeconiomic Status0.728 Ethnicity0.726

How to interpret the funnel plot 95% 99.5% 95% 99.5%

Additions of demography 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 Comorbid Score (95% CI)

Variation in comorbidity between centres Centre Prevalence of Diabetes Centre Prevalence of Claudication

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 Age & Sex.722 Plus Late Referral.784 Plus Primary Renal Disease.782 Plus Comorbidity.777 Age, Sex, SES, Ethnicity, Year Specificity Sensitivity

Importance of comorbidity in other settings Admissions per year after starting RRT Condition Absent Condition Present Percent Increase Age > Modality Change Late Referral Diabetes Myocardial Infarct Heart Failure No. of Comorbidities Mean Transplant Length of Stay95% CI – – – 18.5 >= – 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 School of Health and Related Research