Subspecialty evaluation of chronically ill hospitalized patients with suspected immune defects

The diagnosis of primary immunodeficiency is suggested by recurrent or unusual infections and inflammatory and autoimmune conditions. Because the diversity of immune defects and clinical presentations poses a diagnostic challenge in hospital populations, a computer algorithm was devised to help identify patients.

To assess use of pertinent subspecialty clinics by patients with clinical features of immunodeficiency.

Using a validated algorithm based on International Classification of Diseases, Ninth Revision (ICD-9), codes applied to The Mount Sinai Hospital billing records, we investigated hospitalized patients, 60 years or younger, who had been diagnosed as having conditions associated with immunodeficiency, excluding those with confounding medical conditions. Immunodeficiency-related disease codes were given a weighted score based on relative severity and expressed as a sum for admissions between January 1, 1999, and December 31, 2003. Demographic features, subspecialty care, and clinic attendance were determined.

The 296 computer-identified patients with illnesses characteristic of immunodeficiency were 35.8% Hispanic, 27.0% African American, and 21.6% white; their median age was 13.3 years. Patients were hospitalized 1,261 times, or a median of 4.2 times each (range, 1-42 times), and had 5,700 diagnoses. Of the patients, 75.0% received primary care at The Mount Sinai Hospital. Although the most common diagnosis was pneumonia (n = 243), 45% of patients never received allergy/immunology or pulmonary subspecialty care.

Despite receiving primary medical care at the same hospital, many frequently hospitalized subjects with features of immunodeficiency do not receive medical care in appropriate subspecialty clinics.