Lien et al. Acta Veterinaria Scandinavica 2010, 52:61 http://www.actavetscand.com/content/52/1/61 regression. Association between systemic blood pressure, microalbuminuria status (no microalbuminuria, microal- buminuria and albuminuria) and health status (clinically healthy versus HAC) were evaluated by Pearson’s chi- square test. All statistical analyses were performed using commercially available software (SPSS, version 13.0, SSPS Inc, U.S.A.). Continuous data are presented as mean ± SD. Statistical significance was determined by a p value < 0.05. Results Systemic blood pressure and presence of microalbuminuria/albuminuria in clinically normal dogs (n = 100) The mean systemic pressure of 100 clinically healthy dogs was 152.8 ± 27.3 mmHg. One (1%, 1/100) was hypotensive, 87% (87/100) were normotensive, and 12% (12/100) were hypertensive. Among the 100 clinically healthy dogs, 53% (53/100) did not have microalbumi- nuria, 45% (45/100) had microalbuminuria, and 2% (2/100) had albuminuria (Table 2). Systemic blood pressure and microalbuminuria/ albuminuria in dogs affected with HAC (n = 70) The mean systemic arterial pressure in dogs affected with HAC was 151.7 ± 32.1 mmHg. None was hypoten- sive, 68.6% (48/70) were normotensive, and 31.4% (22/70) were hypertensive. In 70 dogs with HAC, 12.9% (9/70) did not have microalbuminuria, 38.6% (27/70) had microalbuminuria, and 48.6% (34/70) had albumi- nuria (Table 2). Systemic blood pressure, presence of microalbuminuria/ albuminuria and results of ACTH stimulation tests in dogs affected with PDH (n = 40) The mean systemic blood pressure in dogs affected with PDH was 142.2 ± 24.9 mmHg. None was categorized as hypotensive, 80% (32/40) were normotensive, and 20% (8/40) were hypertensive. Among the 40 dogs affected with PDH, 15% (6/40) did not have albuminuria, 52.5% (21/40) had microalbuminuria, and 32.5% (13/40) had albuminuria. Pre- and post-ACTH cortisol concentra- tions in the dogs affected with PDH were 4.6 ± 2.9 (ran- ging from 1.9 to 14.1) and 25.5 ± 11.6 (ranging from 21.6-63.1) μg/dL, respectively (Table 2). Systemic blood pressure, presence of microalbuminuria/ albuminuria and results of ACTH stimulation tests in dogs affected with ADH (n = 30) The mean systemic blood pressure in dogs affected with ADH was 164.1 ± 36.7 mmHg. None was hypotensive, 53.3% (16/30) were normotensive, and 46.7% (14/30) were hypertensive. Among the 30 dogs with ADH, 10% (3/30) did not have microalbuminuria, 20% (6/30) had Page 4 of 6 microalbuminuria, and 70% had albuminuria. Pre- and post-ACTH cortisol concentrations in dogs affected with ADH were 8.5 ± 6.0 (ranging from 2.9 to 28.7) and 33.2 ± 23.7 (ranging from 23.6-110.2) μg/dL, respectively (Table 2). Comparison of systemic blood pressure and presence of microalbuminuria/albuminuria between clinically healthy dogs and dogs affected with HAC The mean systemic blood pressure was not different between clinically healthy dogs and dogs with HAC (p = 0.803). However, incidence of hypertension between clinically healthy dogs and dogs affected with HAC was significantly different (p = 0.019). Presence of microal- buminuria and albuminuria in clinically healthy dogs and dogs affected with HAC was significantly different (p < 0.001); significantly higher incidence of microalbu- minuria, but significantly lower incidence of albuminuria in clinically healthy dogs compared to dogs affected with HAC. Overall, presence of microalbuminuria or albumi- nuria was not associated with the status of blood pres- sure in either clinically healthy dogs or dogs with HAC (p = 0.141). Comparison of systemic blood pressure, presences of microalbuminuria/albuminuria and results of ACTH stimulation test between dogs affected with PDH and ADH The mean systemic blood pressure was significantly different between dogs affected with PDH and ADH (p = 0.004). Incidence of hypertension in dogs affected with PDH and ADH was significantly different (p = 0.017). Presence of microalbuminuria and albumi- nuria in dogs affected with PDH and ADH was signifi- cantly different (p = 0.007). However, albuminuria was not associated with the status of blood pressure (p = 0.306). Both pre- and post-ACTH cortisol concentrations between dogs affected with PDH and ADH were signifi- cantly different (p < 0.001). No correlation between sys- temic blood pressure in either pre-ACTH (r = 0.095, p = 0.479) or post-ACTH cortisol concentrations (r = 0.130, p = 0.326) was found. Overall, the incidence of hypertension was highest in dogs with ADH, followed by dogs with PDH, with the lowest levels in clinically healthy dogs (p = 0.019); inci- dences of albuminuria followed the same pattern: highest incidence in dogs with ADH, and lowest level in clinically healthy dogs (p < 0.001); but microalbuminuria showed a different pattern: clinically healthy dogs had highest inci- dence and dogs with ADH had lowest incidence. Discussion The incidence of hypertension in dogs affected with HAC has been reported to range from 52.6 (n = 10/16)