Uncontrolled diabetes and health care utilisation: panel data evidence from Spain.

Despite size and relevance of uncontrolled diabetes, robust evidence on its effects on health care utilisation is very limited, especially among European countries. We employed longitudinal administrative data from Spain (2004-2010) to explore the relationship between uncontrolled type 2 diabetes and health care utilisation. We used a biomarker (glycated haemoglobin, HbA1c) to detect the presence of uncontrolled diabetes and explore its effects on both primary and secondary health care. We estimated a range of panel count data models, including negative binomials with random effects, dynamic and hurdle specifications to account for unobserved heterogeneity, previous utilisation and selection. We found uncontrolled diabetes in between 27 and 30% of patients of both genders. Our estimates suggested that although women appeared to systematically consume more health care compared to men, their consumption levels did not seem to be influenced by uncontrolled diabetes. Conversely, among men uncontrolled diabetes increased the average number of GP visits per year by between 3 and 3.4%, specialist visits by 5.3-6.1%, depending on specifications, and also extended annual hospital length of stay by 15%. We also found some evidence of heterogeneity in utilisation based on the level of uncontrolled diabetes among male individuals. Overall, our results suggested the need for different diabetes management plans depending on gender and levels of glycaemic control.