Evaluation of Length of Hospital Stay Joining Educational Programs for Type 2 Diabetes Mellitus Patients: Can We Control Medical Costs in Japan?

Abstract

Diabetes has become a growing concern in Japan, both medically and financially. The medical cost of diabetes was estimated at 1215 billion yen for fiscal year 2011. We analyzed the length of stay (LOS) in a hospital for type 2 diabetes mellitus patients who participated in educational programs to determine factors affecting LOS. Data on 991 patients obtained from 28 Red Cross hospitals in 2008 were used. For the analysis, we used the Box-Cox transformation model and Hausman test. The results revealed that patients aged 75 years and above and those with comorbidities and complications were prone to longer LOS. The analysis also revealed significant differences in LOS across the hospitals, even after controlling for patient characteristics. Finally, we applied the least squares method to determine the effects of hospital and regional factors and revealed that patients' LOS was affected by the region's average LOS. Regional corporations and networks appeared to be important in improving educational programs.

Comparison of the Length of Stay and Medical Expenditures among Japanese Hospitals for Type 2 Diabetes Treatments: The Box-Cox Transformation Model under Heteroscedasticity

“…The data included patients' LOS, medical expenditures, age, gender, health-related conditions and medical treatments. For details, see Nawata and Kawabuchi [23]. The original dataset included 27,861 patients, and 22,430 patients (80%) were classified under the DPC code 100070xxxxxx0x (type 2 diabetes patient without diabetic ketoacidosis and secondary diseases).…”

“…Using the BC MLE and N-estimator, we can conduct the test for the "small σ" assumption (the null hypothesis is that the "small σ" assumption holds) by the Hausman test [33]. For details, see Nawata and Kawabuchi [23] [24].…”

“…(Diabetes can be classified as type 1 or type 2; for details, see ADA [22].) Nawata and Kawabuchi [23] [24] studied the length of stay (LOS) in hospitals for type 2 patients who joined educational programs for lifestyle improvement rather than treatment (hereafter educational hospitalization). They found a large variation among hospitals in average length of stay (ALOS), and that ALOS at some hospitals was unreasonably long even after eliminating the influence of patient characteristics.…”

Asymptotic Efficiency of the Maximum Likelihood Estimator for the Box-Cox Transformation Model with Heteroscedastic Disturbances

“…Suppose that ij t is the explanatory variable of observation j in group i (for example, LOS of patient j in hospital i in Nawata and Kawabuchi [6]- [11]). I consider the BC model:…”

“…It is sometimes necessary to consider a model combining these two models. Nawata and Kawabuchi [6]- [11] analyzed length of stay (LOS) in Japanese hospitals using the BC model. They found that the variances among hospitals were often very different among hospitals even after the transformation.…”