Frequencies and rankings of diagnoses are based on principal, or first-listed, diagnosis. The unit of analysis is the inpatient stay rather than the patient. All discharges have been weighted to produce national estimates. Total charges in HCUP data are the amount the hospital charged or billed for the entire hospital stay and do not necessarily reflect reimbursements or costs. Charge data were present for 98 percent of all discharges.
Charges are generally higher than costs.
Because the NIS is limited to inpatient hospital data, conditions treated in outpatient settings are not reflected here. Many medical terms are used throughout this report. For help in understanding these terms, refer to the Glossary .