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Impact Of New Cause-Of-Death Classification System                                                                        
                                                                                                              
A new system for collecting and presenting cause-of-death data went into effect in 1999.                      
The new system includes:                                                                                      
Conversion from ICD-9 to ICD-10 medical codes.                                                                
Changes in rules for coding medical information and selecting underlying cause of death.                      
Revised cause-of-death tabulation lists.                                                                      
If you have questions about the impact of this new system, see the NCHS web page cited below or               
contact Dorene Harris at (501) 661-2369 or at mdharris@healthyarkansas.com                                    
                                                                                                              
1999 cause-of-death data are not directly comparable to previous years.                                       
The changes listed above have caused a lack of continuity between 1999 and previous data.  What               
may appear to be a sudden increase or decrease in the number of deaths from certain causes may                
only be the result of changes in the criteria used to assign a death to that cause.   Also, tracking          
some diseases and injuries from the old to the new reports will be complicated by completely new              
ICD codes, rearranged categories, title changes, and new tabulation lists.                                    
                                                                                                              
Conversion from ICD-9 to ICD-10.  The new, alphanumeric ICD-10 medical codes give much                        
more detail than was possible under ICD-9.   The impact of this increased cause-of-death detail may           
be seen in our 1999 Detailed Mortality Report.  In addition to changing all medical codes, ICD-10             
has redefined, reclassified, and regrouped some diseases and injuries.  Detailed information on               
ICD-10, including a downloadable list of all ICD-10 codes and titles is available on the web page of          
the National Center for Health Statistics (NCHS) at http://www.cdc.gov/nchs/about/major/dvs/icd10des.htm                                                          
                                                                                                              
Revision of criteria used to select underlying cause of death.  The UCOD used in mortality reports            
is selected by reviewing medical information reported on death certificates, assigning ICD codes to           
all conditions, determining the relationship among the reported conditions, and selecting which               
condition started the sequence of events leading to death.  This process is standardized under a              
series of  rules developed by NCHS.   This selection process has been revised for 1999 data to                
reflect more current medical knowledge about causes and complications of diseases and injuries.               
                                                                                                              
New cause-of-death tabulation lists.   Many of the lists used to present Arkansas mortality data are          
based on standardized tabulation lists developed by NCHS.  These lists have been revised for 1999.            
                                                                                                              
Comparability ratios.   NCHS has calculated comparability ratios to measure the impact of the                 
conversion to ICD-10 and changes in UCOD selection procedures.  After coding a year's worth of                
death certificates using both systems, they divided the number of deaths assigned to a cause under            
the ICD-10 system by the number of deaths assigned to the same cause under the ICD-9 system.   A              
comparability ratio of 1.0000 means that the same number of deaths was assigned to that cause                 
under both systems: 1.2000 indicates 20% more were classified to that cause under ICD-10:                     
0.8000 indicates a 20% decrease.   The number of deaths assigned to a cause in 1998 may be                    
multiplied by the comparability ratio and compared to the number of deaths from that cause in                 
1999.  This will show if there was an "actual" change in the number of deaths from that cause, or if          
the increase or decrease can be attributed to the changes in the system used to collect these data.           
                                                                                                              
A list of these comparability ratios is published by NCHS on their web address cited above.                   
                                                                                                              
                                                                                                              
                                                                                                              
                                                                                                              
 
 
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