Potential applicability of the importation risk index for predicting the risk of rarely imported infectious diseases

Table 1 Assessment for the validity of importation risk index as a predictor for Rabies importation by logistic regression (GLM) and generalized estimating equation (GEE) analysis

Model	Type of travel-volume	GLM			GEE
Model	Type of travel-volume	Coef¹	p value¹	AUC²	Coef¹	p value¹	AUC²
Rabies Model 1	Total	0.133	< 0.001	0.728	0.133	< 0.001	0.728
Rabies Model 2	1st class	5.748	< 0.001	0.682	6.289	< 0.001	0.682
Rabies Model 3	2nd class	4.251	< 0.001	0.689	4.623	< 0.001	0.689
Rabies Model 4	Economy class	0.141	< 0.001	0.734	0.140	< 0.001	0.734

Note: The response variable is whether there is at least one imported case between two specific countries in a specific year. The importation risk index (IR index) was defined as product of travel-volume and disease burden in the source countries. As there were four variables for the travel-volume (number of 1st class passengers, number of 2nd class passengers, number of economy class passenger and total number of all passengers), four IR indices can be calculated. Four logistic regression models and four GEE models were fitted using the four IR indices, respectively as the index was the only independent variable in each model. The IR index variable in these models were rescaled by dividing 10^5 to increase coefficient. P values of Hosmer and Lemeshow goodness of fit in the GLM models were 0.429, 0.504, 0.038, and 0.348 for the model 1–4, respectively, indicating lack of fit for the Rabies Model 3
¹coefficients and p values for importation risk index
²area under curve for Receiver operating characteristic

ISSN: 1471-2458