studying injuries using the national hospital discharge survey marni hall, ph.d. hospital care...
TRANSCRIPT
![Page 1: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/1.jpg)
Studying Injuries Using the National Hospital Discharge Survey
Marni Hall, Ph.D.Hospital Care Statistics Branch,
Division of Health Care Statistics
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICESCenters for Disease Control and PreventionNational Center for Health Statistics
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICESCenters for Disease Control and PreventionNational Center for Health Statistics
![Page 2: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/2.jpg)
Outline of this presentation
• Present general information about the design of the National Hospital Discharge Survey (NHDS)
• Discuss decisions that have to be made when designing injury research using NHDS
• Highlight issues particularly related to trend analyses in
![Page 3: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/3.jpg)
Upcoming Chartbook
Trends in Injury Hospitalization, United States, 1979-2001
by Melissa Heinen, Marni Hall, Manon Boudreault, and Lois Fingerhut
![Page 4: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/4.jpg)
NHDS
a national probability sample of short-stay non-federal hospitals - conducted
every year since 1965
provides data on discharges or hospitalizations – not individuals
2002 data - now available
2003 data - available in the winter
![Page 5: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/5.jpg)
NHDS Design
Three stage design
Geographic Units Hospitals Discharges
![Page 6: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/6.jpg)
Data Collection
Automated – 40%
Manual – 60%
![Page 7: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/7.jpg)
Patient Data
• Sex
• Race
• Age
• Expected source of payment
• Discharge status – including deaths
![Page 8: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/8.jpg)
Facility Characteristics
• Geographic region
• Bed size
• Ownership
![Page 9: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/9.jpg)
Medical Data
Coded according to the International Classification of Diseases, 9th Revision,
Clinical Modification (ICD-9-CM)
• Diagnoses
• Surgical and nonsurgical procedures
![Page 10: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/10.jpg)
Additional Variables
• Days of care• Month of admission/discharge• Weight• DRG – diagnosis-related group• Available since 2001 NHDS
– Source of Admission– Type of Admission
![Page 11: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/11.jpg)
2002 NHDS
445 hospitals and 327,000 discharges were sampled
Weighted number of discharges was 33.7 million
![Page 12: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/12.jpg)
Weights
• Must use weighted data to obtain national estimates
• Each record has a weight
• Must calculate the sum the weights of the records – one line of programming
![Page 13: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/13.jpg)
Estimates have standard errors
A standard error is the sampling variability that occurs by chance
because only a sample rather than the entire universe is surveyed
![Page 14: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/14.jpg)
For more design information
Plan and Operation of the National Hospital Discharge Survey: 1988
Redesign Vital and Health Statistics, 1(39). 2000
http://www.cdc.gov/nchs/data/series/sr_01/sr01_039.pdf
![Page 15: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/15.jpg)
Designing Injury Research Project
• Determine what injury definition will be used – all injuries or selected injuries – what ICD-9-CM codes
• Decide how you will count injury patients• Select the data you will report• Evaluate whether and how external cause codes
will be used
![Page 16: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/16.jpg)
Injury definitions• Definition developed by injury experts, e.g. the State and
Territorial Injury Prevention Directors Association (STIPDA) reported in Consensus recommendations for using hospital discharge data for injury surveillance, 2003
• Use existing categorization of codes – e.g. the Barell Matrix which defines injuries by type and body region in Injury Prevention, 8, 2002
• Injury and Poisoning Chapter of the ICD-9-CM – codes 800 to 999 – includes “true injuries” and “medical injuries”
![Page 17: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/17.jpg)
• Have a specific ICD-9-CM code(s)
• Be relatively common in hospitalized patients or you will have to combine data over multiple years in order to get reliable estimates
Diagnoses selected for study should
![Page 18: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/18.jpg)
Reliability • To be reliable, estimates must be based on at
least 30 records, and have a relative standard error of less than 30 percent - these usually produce weighted estimates of less than 5,000
• Estimates based on 30-59 records may be
unreliable and should be used with caution – these usually produce weighted estimates from 5,000-9,000
![Page 19: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/19.jpg)
Counting injury patients
If you want the number of patients hospitalized because of an injury – count the first-listed diagnoses
If you want the number of hospitalized patients who have one or more injuries – count any-listed diagnoses
![Page 20: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/20.jpg)
Counting injuries
If you want the number of injuries and not the number of patients – count all-listed diagnoses
![Page 21: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/21.jpg)
Hospital discharges with fractures, 2002
Principal or first listed
Any listed All listed
995,000
1,387,000
1,609,000
![Page 22: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/22.jpg)
Injury chartbook includes the following data
• Injury discharges by age and sex• Type and body region of injuries• Average number of diagnoses• Days of care/average length of stay• Expected source of payment• Discharge disposition• Percent with, and types of, external cause codes
![Page 23: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/23.jpg)
Choices involving external cause codes
• Evaluate the percent of injury patients with external cause codes – how complete is it?
• If you decide you will use external cause codes, will you use just the first code or all codes?
• Consider using a previously developed categorization, e.g. - the External Cause of Injury Matrix
![Page 24: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/24.jpg)
Challenges in studying trend data
• Coding changes over time
• Size and availability of data files
• Presenting the data
• Interpreting the data
![Page 25: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/25.jpg)
Different versions of the International Classification of
Diseases
• 8th revision used 1970-78
• 9th revision used 1979-2004 – with addenda since 1986
![Page 26: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/26.jpg)
Size and availability of NHDS data
• Single year files can be downloaded from the NHDS website and unzipped using free software. These include DRG’s.
• Multiple year files are on CD’s, rather than our website, due to their large size. They can be obtained by calling our office (301-458-4321). They do not include DRG’s.
![Page 27: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/27.jpg)
Presenting the data
Age adjustment - Eliminates the differences in observed rates that result from age differences in population composition
over time
![Page 28: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/28.jpg)
Presenting the data
Use of the log scale - allows the presentation of estimates with a very
wide range on the same graphand
facilitates comparison of the percent change of estimates over time
![Page 29: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/29.jpg)
Presenting the data
Measures of change
AAPC – Average annual percent change from 1979-2001
APC – Average percent change for 1979-2001
![Page 30: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/30.jpg)
Interpreting the results
Health service system changes which contributed to the decrease in hospitalization overall and for injuries
• Reform of Medicare hospital payment• Increased utilization review of hospital care• Growth in managed care• Expansion and coverage of ambulatory
surgery
![Page 31: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/31.jpg)
Interpreting the results
Injury prevention activities which contributed to the decrease in hospitalization for injuries
• Encouragement of the use of safety belts and helmets
• Safer automobiles (air bags)• Safer roads• Improvements in home and workplace safety• Poison control centers
![Page 32: Studying Injuries Using the National Hospital Discharge Survey Marni Hall, Ph.D. Hospital Care Statistics Branch, Division of Health Care Statistics](https://reader036.vdocument.in/reader036/viewer/2022062423/56649ee15503460f94bf1239/html5/thumbnails/32.jpg)
For more information:
• Check our website www.cdc.gov/nchs/about/major/hdasd/nhds.htm
• Phone: 301-458-4321
• Fax: 301-458-4032• Email: [email protected]