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Comparison of Two Surveys of Hospitalization: The National Hospital Discharge Survey and the NHANES I Epidemiologic Followup Study

Discharge Survey and the NHANES I Epidemiologic Followup Study Hospitalization is an important measure of health care utilization. A comparison of hospitalization experience between two National Center for Health Statistics (NCHS) surveys is the focus of the report, "Comparison of Two Surveys of Hospitalization: The National Hospital Discharge Survey and the NHANES I Epidemiologic Followup Study." NCHS collects hospitalization data annually through its National Hospital Discharge Survey (NHDS), a survey of patients encounters in short-stay hospitals. Data collected from the NHDS provide national estimates on hospital diagnoses, average lengths of stay, and surgical and nonsurgical procedures performed. The NHDS, the primary source of data on national hospitalization patterns, does not permit analyses of the determinants of hospital use primarily because the survey does not collect information beyond standard demographic characteristics listed on hospital admission forms.

Additionally, the survey collects information only on persons who use hospital care rather than for all persons at risk of hospitalization.

NCHS' National Health and Nutrition Examination Survey (NHANES) focuses on baseline data of each respondent, including potential risk factors as measured by physician examinations, laboratory tests, and interviews. A longitudinal component of the survey, the NHANES Epidemiological Follow-up Study was designed to study men and women aged 35 years and over who were part of the NHANES I study between 1971-1975. Follow-up surveys collected information on health-related outcomes, including overnight stays in hospitals. Therefore, by comparing the NHDS data to the NHEFS population, it is possible to study the relationship between baseline risk factors and subsequent hospital use.

Most notable results from the combined study show that hospital stays per 1,000 population were lower in the NHEFS than in the NHDS in all age-sex groups at the beginning of the study, but the differences had almost disappeared by 1987. Lengths of stay, although somewhat longer in the NHEFS, matched the NHDS more closely.