From ICD-9 to ICD-10 Evaluating the Impact for

From ICD-9 to ICD-10: Evaluating the Impact for Healthy People 2010 Manon Boudreault, M. P. H. National Center for Health Statistics Healthy People 2010

International Classification of Diseases (ICD) History • Since 1900, ICD revised about every 1020 years • All revisions have had an impact on comparability • Variations in statistics due to differing coding rules used rather than a change in disease entity Healthy People 2010

History…. • Beginning with deaths occurring in 1999, ICD-10 implemented • Many systematic differences between ICD 9 and ICD-10 • Between 1979 and 1998, ICD-9 in use Healthy People 2010

Major Differences in ICD-10: • Rules for coding and selecting underlying cause of death have changed • Greater detail about the type or site of the disease (from about 5, 000 to 8, 000 categories ) • An increased number of perinatal codes Healthy People 2010

Major differences between ICD -9 and ICD-10 … • Chapters have been added and rearranged • Cause-of-death titles have been changed and regrouped • Alphanumeric codes Healthy People 2010

Cause-Specific HP 2010 Mortality Objectives • About 40 objectives, most use the National Vital Statistics System as data source Healthy People 2010

Baseline History • Baseline data were initially classified and coded to: World Health Organization’s Ninth Revision of the International Classification of Diseases (ICD-9) • Used by virtually all countries to code and classify causes of death Healthy People 2010

Comparability Study: Measure Effect of Revision • Same death certificates coded to each ICD version • Comparability Ratio (derived from dual classification): » ICD-10 coded deaths » divided by » ICD-9 coded deaths • May be able to adjust older data (total) with comparability ratio Healthy People 2010

Comparability Ratio C= i D D i, ICD-10 i, ICD-9 Measures discontinuity related solely to a revised ICD Healthy People 2010

HP 2010 Selected Estimated CRs* Obj. No. Cause 13 -14 HIV 16 -1 f 24 -1 Same Deaths coded to ICD-10 Same Deaths coded to ICD-9 CR= (ICD-10 divided by ICD-9) 1. 14 95% CI 12, 765 11, 150 (1. 14, 1. 15) Birth Defects 5, 950 7, 025 . 8470 (. 8362, . 8577) Asthma 4, 217 4, 718 . 8938 (. 8819, . 9057) 1, 158 969 (all ages) 26 -3 Druginduced 1. 195 (1. 15, 1. 24) *Source: National Vital Statistics System-Mortality, NCHS (Preliminary data), Comparability Ratio (CR) calculated using large sample of 1996 deaths, except for HIV Healthy People 2010 deaths (1998 deaths)

Comparability Ratio (CR) … • Currently available for objectives where data source is the National Vital Statistics System. Mortality • Where HP 2010 ICD-9 codes are different, CRs have been calculated in a separate HP 2010 report • Is not appropriate to apply to data for objectives that use “multiple-cause-of-death” (e. g. , diabetes) Healthy People 2010

Comparability-Modified Deaths (or Rate) CM D i, ICD-9 = D i, ICD-9 Healthy People 2010 C i

Comparability Ratio CAUTION!!!! • CR of 1 does not necessarily mean cause of death was totally unaffected by revision • Unknown if appropriate to use on age-, race-, sex-, or State-specific mortality data • In theory CRs could be applied to subgroups, in practice there are differences in cause-of-death distribution Healthy People 2010

HP 2010 Steering Committee Response • Unanimous vote to change baseline years for cause-specific mortality objectives to 1999 • Data years will be based on the same classification system (ICD-10) • 1997 or 1998 (primarily) baselines replaced Healthy People 2010

Effect on 2010 Targets • Baseline revisions were minor • No targets were changed at the time baselines were changed Healthy People 2010

Other HP 2010 Mortality Sources • U. S. Renal Data System (obj. 4 -2) • Census of Fatal Occupational Injuries (obj. 20 -01) • Fatality Analysis Reporting System (obj. 15 -15 b, 15 -16, 26 -1) • National Surveillance System for Pneumoconiosis (obj. 20 -04) Healthy People 2010

Other HP 2010 Mortality Data Sources • Baseline evaluations, in process now • Case-by-case basis, • may not use ICD coding solely in their identification Healthy People 2010

From ICD-9 to ICD-10: Impact on HP 2010 data • Most HP 2010 cause-specific mortality objectives baselines changed • Some groupings of death codes changed (noted in Tracking HP 2010, operational definitions) • Food allergy deaths –anaphylaxis (obj. 10 -4) now measurable with ICD-10, specific codes Healthy People 2010

Other Vital Statistics Changes Impact on HP 2010 data • Upcoming certificate changes: – More complete race data expected – Some objectives will become measurable: Gestational diabetes (Objective 5 -08) Recommended weight gain during pregnancy (Objective 16 -12) Healthy People 2010

For More Information On. . • Comparability ICD-9/10… Session 24. . next Concurrent Session …Diplomat Room • Comparability report http: //www. cdc. gov/nchs/products/pubd/nvsr/49/4 9 -12. htm • Mortality Database… Session 38 …Wednesday…Ambassador Ballroom • Natality Data Files… Session 42 …Wednesday…Congressional Room Healthy People 2010