Methods and Limitations
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Methodology

We estimated the number of hospital discharges involving persons with diabetes using data from the National Hospital Discharge Survey (NHDS), National Center for Health Statistics, Centers for Disease Control and Prevention. NHDS collects data on hospital discharges from a sample of short–stay, nonfederal hospitals in the United States. Data collected include information on patients' age, race, sex, and length of stay, and on seven diagnoses (one primary and six secondary diagnoses) and four surgical procedures. Methods used for conducting the survey have been described previously.1,2

We examined hospital discharges for which diabetes (ICD–9 code 250) was listed as first-listed of seven diagnoses. The number may not add up to the total since the total includes races other than white and black. Rates were calculated using resident population estimates and estimates of the population with diabetes. Rates were adjusted to the 2000 U.S. Standard Population using four age groups (0–44, 45–64, 65–74, 75+).3

Because the estimates were produced prior to the year 2000, a slight difference may occur between crude and age-adjusted rates for 2000.

 

Data Limitations

Hospitalizations involving persons with diabetes may be underestimated because long–term and federal hospitals are not included in the NHDS sample. Race-specific discharges are particularly underestimated because a substantial proportion of discharges are missing racial classification and missing values for race are not imputed.4

Because NHDS samples hospital discharges and not individual persons, NHDS hospital discharge rates for diabetes–related diseases and procedures may not necessarily reflect rates per person; that is, persons who are hospitalized more than once in a year may be counted more than once.
 

References

  1. Dennison C, Pokras R. Design and operation of the National Hospital Discharge Survey: 1988 redesign. Vital and Health Statistics 2000;1(39).
  2. Hall MJ, DeFrances CJ, Williams SN, Golosinskiy A, Schwartzman A. National Hospital Discharge Survey: 2007 summary. Vital and Health Statistics 2010; 29.
  3. Klein RJ, Schoenborn CA. Age adjustment using the 2000 projected U.S. population. Healthy People Statistical Notes, no. 20. Hyattsville, Maryland: National Center for Health Statistics. January 2001.
  4. Kozak LJ. Underreporting of race in the National Hospital Discharge Survey. Vital and Health Statistics 1995; 265.