The Best Use of the Charlson Comorbidity Index With Electronic Health Care Database to Predict Mortality

• Published in: Medical care 2016-02, Vol.54 (2), p.188-194
• Main Authors: Bannay, Aurélie, Chaignot, Christophe, Blotière, Pierre-Olivier, Basson, Mickaël, Weill, Alain, Ricordeau, Philippe, Alla, François
• Format: Article
• Language: English
• Subjects: Adult; Aged; Calibration; Comorbidity; Electronic Health Records; Electronic Health Records - statistics & numerical data; Female; France; Humans; Insurance Claim Review; Insurance Claim Review - statistics & numerical data; International Classification of Diseases; Life Sciences; Male; Middle Aged; Mortality; National health insurance; Original Article; Prognosis; Risk Adjustment; Risk Adjustment - methods; Santé publique et épidémiologie; Survival analysis
• ISSN: 0025-7079; 1537-1948
• DOI: 10.1097/MLR.0000000000000471

BACKGROUND:The most used score to measure comorbidity is the Charlson index. Its application to a health care administrative database including International Classification of Diseases, 10th edition (ICD-10) codes, medical procedures, and medication required studying its properties on survival. Our objectives were to adapt the Charlson comorbidity index to the French National Health Insurance database to predict 1-year mortality of discharged patients and to compare discrimination and calibration of different versions of the Charlson index. METHODS:Our cohort included all adults discharged from a hospital stay in France in 2010 registered in the French National Health Insurance general scheme. The pathologies of the Charlson index were identified through ICD-10 codes of discharge diagnoses and long-term disease, specific medical procedures, and reimbursement of specific medications in the past 12 months before inclusion. RESULTS:We included 6,602,641 subjects at the date of their first discharge from medical, surgical, or obstetrical department in 2010. One-year survival was 94.88%, decreasing from 98.41% for Charlson index of 0–71.64% for Charlson index of ≥5. With a discrimination of 0.91 and an appropriate calibration curve, we retained the crude Cox model including the age-adjusted Charlson index as a 4-level score. CONCLUSIONS:Our study is the first to adapt the Charlson index to a large health care database including >6 million of inpatients. When mortality is the outcome, we recommended using the age-adjusted Charlson index as 4-level score to take into account comorbidities.