TEMPORAL AND GEOGRAPHICAL VARIATION IN THE ATLANTIC USE OF INTRAVENOUS IMMUNOGLOBULIN: AN ECOLOGICAL STUDY FROM 2006-2007 TO 2013-2014.

Abstract

BACKGROUND: The use of intravenous immunoglobulin (IVIG) has been increasing worldwide and in Canada. The high use of IVIG can partially be explained by the publically funded health care system in Canada, higher sensitivity for diagnosing immunodeficiency disease, absence of supply demand issues of blood products, and the use of IVIG for unlabeled indications. There are other causes for high use, and non-random variations point towards the presence of modifiable underlying explanations influencing utilization. Although variation studies have been used to explore the utilization practices in other health disciplines, this type of research has never been done to study variations in the use of IVIG. This study measures the extent of geographical and temporal variations in the provincial age- and sex-adjusted rates of use of IVIG/1,000 (provincial rate) in the Atlantic provinces from 2006-2007 to 2013-2014, stratified by indications. METHODS: Geographical and temporal variations are examined on the indirectly standardized rates using descriptive analyses, followed by statistical testing. RESULTS: There are significant effects of each province and each fiscal year on the provincial rates (repeated measures analysis of variance, all p<0.0001). There are statistically significant increases in provincial rate, rates stratified by indications over time in each Atlantic province (Poisson regression, all p<0.0001). NL has the largest number of users of IVIG/1,000 and the largest mean annual usage of IVIG per patient. NL has the largest per capita number of hematologists (21/1,000,000) when compared with the other three Atlantic provinces. The rate of use in autoimmunity is the primary driver of provincial rates (ecologic graphic analysis). CONCLUSION: There is significant temporal and geographical variation in provincial rates of IVIG use in the Atlantic provinces during 2006-2007 to 2013-2014. The emphasis of future research should be at reducing variations in the use of IVIG across Atlantic provinces by minimizing variations in physician related factors.