Lien et al. Acta Veterinaria Scandinavica 2010, 52:61 http://www.actavetscand.com/content/52/1/61 to 86.1% (n = 31/36) [3,4]. In this study, the incidence of hypertension in dogs with HAC was 46.7%, which was significantly higher than the 12% incidence observed in clinically healthy dogs, supporting previous observa- tions that dogs affected by HAC tend to have hyperten- sion [3,4]. However, the incidence of hypertension in dogs affected with HAC was lower than that reported in previous studies. Different methods of blood pressure measurements, definition of hypertension, and case numbers may explain lower incidence in this study. The degree of hypertension is also positively correlated with the duration of the condition rather than with cortisol concentrations [11,18]. In this study, the condition of hyperadrenocorticism was newly diagnosed. Systemic blood pressure was measured at the initial diagnosis. A higher incidence of hypertension might be seen at later stages of the condition. In this study, higher systemic blood pressure and higher incidence of hypertension was associated with ADH com- pared to PDH. This finding has not been reported in dogs affected with hyperadrenocorticism. However, no correla- tion between the cortisol concentrations and systemic blood pressure was found. Similar results were also reported in human patients with Cushing’s syndrome [11,18]. The concentration of cortisol alone may not cause hypertension. Many factors have been found to be involved in development of hypertension in human patients with Cushing’s syndrome, including the duration of hypercortisolaemia, impaired microvascular reactivity, endothelial dysfunctions, and hyperaldosteronemia- asso- ciated arterial wall stiffness and fibrosis [11,18,19,29]. Higher plasma aldosterone concentrations were reported in dogs affected with ADH than in dogs with PDH [6,30]. Nevertheless, aldosterone was not involved in the develop- ment of hypertension in dogs with PDH [30]. Further study regarding association between vascular stiffness, myocardial reactivity and systemic blood pressure in dogs affected with either PDH or ADH is warranted. Incidence of microalbuminuria in clinically healthy dogs in this study (45%) was similar to previous studies, ranging from 19 to 52% [31,32]. Surprisingly, a signifi- cantly lower incidence of microalbuminuria, but a higher incidence of albuminuria was observed in dogs affected with HAC compared to clinically healthy dogs. Microalbuminuria is a well-known risk factor associated with deteriorated renal and cardiovascular diseases in humans [12,14,17,20,21]. It is also associated with survi- val time in chronic renal failure [22]. Nonetheless, microalbuminuria was also found to be associated with various underlying systemic diseases, such as neoplasia, infectious diseases, and immune or inflammatory dis- eases [24,32]. Due to the high incidence of microalbumi- nuria in clinically healthy dogs and the association of this condition with various systemic disorders, the Page 5 of 6 microalbuminuria test may be more useful to screen for subclinical disorders than to detect specific diseases. In this study, incidence of hypertension and albumi- nuria was significantly higher in dogs affected with ADH compared to PDH. This finding has not been reported in dogs affected with HAC. The correlation between systemic blood pressure and albuminuria would be anticipated in dogs with HAC, however, this was not supported in this study. Hypertension is not the only factor associated with presence of albuminuria. Increased urinary albumin excretion rate is also linked to dyslepidaemia, reduced insulin sensitivity, impaired endothelial function and hyper-coagulative status [7]. These complications are commonly seen in both human and canine patients with Cushing’s syndrome [1,16,18,19]. Glomerular changes and subsequently, increases in urinary protein excretion were found with chronic glucocorticoid use [33,34]. These may explain the disassociation between albuminuria and blood pres- sure in these dogs. The cause of albuminuria in dogs affected with HAC can not be answered in this study. Nevertheless, long- term monitoring of albuminuria in terms of treatment and survival time is needed to clarify the importance of albuminuria and HAC in dogs. Conclusions Incidences of hypertension and albuminuria, but not microalbuminuria, were highest in dogs affected with ADH, followed by dogs with PDH, with the lowest levels observed in clinically healthy dogs. However, the pre- sence of albuminuria was not correlated with systemic blood pressure. Acknowledgements The authors also thank Dr. Kai-Chung Chang at the Consulting Center for Statistics and Bioinformatics, College of Bio-Resources and Agriculture, National Taiwan University for assistance with the statistical analyses. Author details 1Azu Clinic for Animals, No. 92, Section 1, Kin-Shan South Road, Taipei 100, Taiwan. 2Institute of Clinical Veterinary Science, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 100, Taiwan. Authors’ contributions YHL participated in the designs of the study and carried out the recruitment of cases of hyperadrenocorticism. She also drafted the manuscript. TYH performed measurement of systemic blood pressure, carried out the analysis of urinary albumin and creatinine, and the recruitment of clinically healthy dogs as control in this study. HPH participated in the designs of the study, carried out the recruitment of cases of hyperadrenocorticism and performed the statistical analysis and the manuscript writing. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 16 March 2010 Accepted: 12 November 2010 Published: 12 November 2010