Changes in intravenous immunoglobulin prescribing patterns during a period of severe product shortages, 1995-2000

Canadian consumption of intravenous immunoglobulin (IVIG) has increased dramatically since it was first marketed in the early 1980s, and Canada is now the world's largest per capita consumer. During the late 1990s, worldwide product shortages of IVIG occurred. This study was designed to identify the disease conditions for which IVIG was being prescribed in academic hospitals during this period, and to explore the effects that IVIG shortages had on prescribing patterns.

Blood bank and pharmacy records of IVIG distribution were collected retrospectively from four Toronto teaching hospitals for the period 1995-2000. These records were then cross-referenced with patient medical records to determine the indication for IVIG administration.

A total of 100,208 g of IVIG was prescribed to 429 patients over a 6-year period. Most of the IVIG consumption was in patients with haematological (22%) or neurological (20%) conditions, in recipients of bone marrow transplants (19%) and in patients with infectious disease-related conditions (including congenital and acquired hypogammoglobulinaemia, 18%). Dermatological conditions (7%) were the most rapidly growing indication for IVIG usage during the 6-year period of review, increasing from 0% of annual IVIG usage in 1995 to 16% in 2000. Over 80% of the diseases treated were supported by published recommendations. After 1997 there was an abrupt decline in the annual number of patients treated, primarily owing to a decline in single-use recipients. Annual consumption of IVIG, however, remained stable.

IVIG shortages were followed by a decrease in the number of single-use recipients, who probably represented empirical use of IVIG; this had little effect on the total amount of IVIG distributed annually. Stricter adherence to currently available published recommendations may not be the optimal means of controlling IVIG use within an academic hospital setting. Rather, emphasis may be better placed on improving the evidence base upon which these recommendations are made, for example by conducting controlled prospective clinical trials.