# Presentation: 848263

## From ICD-9 to ICD-10: Evaluating the Impact for Healthy People 2010 Manon A. Boudreault, M.P.H.

**From ICD-9 to ICD-10: Evaluating the Impact for Healthy People 2010**** ****Manon A. Boudreault, M.P.H.**

**National Center for Health Statistics**

**Technical assistance provided by: Robert N. Anderson, Ph.D.**
**Mortality Statistics Branch, Division of Vital Statistics**

- Healthy People 2010

## International Classification of Diseases (ICD) History

**Since 1900,  ICD revised about every 10-20 years**
**All revisions have had an impact on comparability**
**Revisions cause statistical discontinuities in cause-of-death trends**

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## 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**

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## 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**

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## 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 **

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## Cause-Specific HP2010 Mortality Objectives

**About 40 objectives, most use the National Vital Statistics System as data source**

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## Section Cut & Adapted from:

**Section Cut & Adapted from:**

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## Section Cut & Adapted from:

**Section Cut & Adapted from:**

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## Baseline History

***Baseline data were initially classified and coded to:*****    **
**	****World Health Organization’s Ninth Revision of the International Classification of Diseases ****(ICD-9)**
***The ICD is used by virtually all countries to code and classify causes of death***

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## 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) to measure effect of break  

**Comparability Ratio (derived from dual classification) **
**ICD-10 coded deaths**
**     ****divided by **
**ICD-9 coded deaths**
**May be able to adjust older data (total) to measure effect of break  **

**Comparability Study:**
**Measure Effect of Revision**

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## Comparability Ratio 

**D****i,ICD-10**
**D****i,ICD-9**

**Measures discontinuity related solely to a revised ICD**

**C****i **** ****=**

## HP2010 Selected Estimated CRs* 

| 
Obj. No. | 
Cause | Same Deaths coded to ICD-10  | Same Deaths coded to ICD-9 | CR=
(ICD-10 divided by ICD-9) | 
  95% CI  |
| --- | --- | --- | --- | --- | --- |
| 13-14 | HIV |   12,765 |  11,150 |   1.1448 |  (1.1360, 1.1536) |
| 16-1f | Birth Defects |     5,950 |    7,025 |     .8470 | (.8362, .8577) |
| 24-1 | Asthma
(all ages) |     4,217 |    4,718 |     .8938 | (.8819, .9057) |
| 26-3 | Drug-induced |     1,158 |        969 |   1.1950 | (1.1509, 1.2391) |

- *Source: National Vital Statistics System-Mortality, NCHS,  Comparability Ratio (CR) calculated using large sample of 1996 deaths, except for for HIV deaths (1998 deaths)

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## Comparability Ratio (CR) ...

**Currently available for objectives where data source is the National Vital Statistics System-Mortality**
**Where HP2010  ICD-9 codes are different, CRs have been calculated in a separate HP2010 report**
**Are not appropriate to apply to data for objectives that use “multiple-cause-of-death” (e.g., diabetes)**

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## Comparability-Modified Deaths (or Rate)

**D****i,ICD-9**= **D****i,ICD-9**** **     **C****i**

**CM**

**.**

## Comparability Ratio CAUTION!!!!

**CR of 1 does not necessarily mean cause of death was totally unaffected by revision**
**Unknown if age-, race-, sex-, or State-specific CRs are appropriate**
**In theory CRs should be constant across subgroups, but in practice, differences in cause-of-death distribution may produce some variation in CRs**

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## 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**

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## Recommendations for Analysis

- In graphing trend data, show a break in trend line at 1999
- Use CR to measure the effect of the break
- Official recommendation: don’t adjust long-term trends using the CR
- Where disease categories have been changed in
- 	ICD-10, make comparison with the most nearly comparable ICD-9 category

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## Effect on 2010 Targets	

**Baseline revisions were minor **
**No targets were changed at the time baselines were changed**

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## Other HP2010 Mortality Sources

**U.S. Renal Data System ****(obj. 4-2)**
**Census of Fatal Occupational Injuries ****(obj. 20-01)**
**Fatality Analysis Reporting System                     ****	****	****	****(objs. 15-15b, 15-16, 26-1)**** **
**National Surveillance System for Pneumoconiosis ****(obj. 20-04)**

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## Other HP2010 Mortality Data Sources 

**Baseline evaluations, in process now **
**Case-by-case basis,**
**May not use ICD coding solely in their identification**

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## From ICD-9 to ICD-10: Impact on HP2010 data 

**Most HP2010 cause-specific mortality objectives baselines changed**
**Some groupings of death codes changed (noted in Tracking HP2010, operational definitions)**
**Food allergy deaths –anaphylaxis  (obj. 10-4) now measurable with ICD-10, specific codes**

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## Other Vital Statistics ChangesImpact on HP2010 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)**

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