Notifiable disease surveillance systems are critical for communicable disease control, and accurate and timely reporting of hospitalized patients who represent the most severe cases is important. A local health department in metropolitan Denver used inpatient hospital discharge (IHD) data to evaluate the sensitivity, timeliness, and data quality of reporting eight notifiable diseases to the Colorado Electronic Disease Reporting System (CEDRS).
Using IHD data, we detected hospitalized patients admitted from 2003 through 2005 with a discharge diagnosis associated with one of eight notifiable diseases. Initially, we compared all cases identified through IHD diagnoses fields with cases reported to CEDRS. Second, we chose four diseases and conducted medical record review to confirm the IHD diagnoses before comparison with CEDRS cases.
Relying on IHD diagnoses only, shigellosis, salmonellosis, and Neisseria meningitidis invasive disease had high sensitivity (≥90%) and timeliness (≥75%); legionellosis, pertussis, and West Nile virus infection were intermediate; and hepatitis A and Haemophilus influenzae (H. influenzae) invasive disease had low sensitivity (≥90% and timeliness to ≥80% for H. influenza invasive disease, legionellosis, and pertussis; however, hepatitis A retained suboptimal sensitivity (67%) and timeliness (25%).
Hospital discharge data are useful for evaluating notifiable disease surveillance systems. Limitations encountered by using discharge diagnoses alone can be overcome by conducting medical record review. Public health agencies should conduct periodic surveillance system evaluations among hospitalized patients and reinforce notifiable disease reporting among the people responsible for this activity.