Key result
Baseline plasma renin activity (P=0.44) and plasma aldosterone concentration (P=0.10) were not significantly different among hyperthyroid cats with or without concurrent hypertension.
Why the study?
Does RAAS activation differ between hyperthyroid cats with and without concurrent hypertension?
Case-Control (n=99)
Does RAAS activation differ between hyperthyroid cats with and without concurrent hypertension?
p-value: p=0.44
RAAS activation occurs in hyperthyroid cats but is not associated with the development of hypertension.
No evidence of differential RAAS activation by hypertension status in hyperthyroid cats; hypothesis-generating for alternative mechanisms.
BACKGROUND: Hypertension is present in some hyperthyroid cats at diagnosis or can develop after treatment for hyperthyroidism. Activation of the renin-angiotensin-aldosterone system (RAAS) could be involved in the pathogenesis of hypertension. HYPOTHESIS: Hyperthyroid cats that develop hypertension before or after treatment for hyperthyroidism will have greater RAAS activation than normotensive cats. ANIMALS: Ninety-nine hyperthyroid cats. METHODS: Retrospective case-control study. Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in untreated hyperthyroid hypertensive cats (HT-Pre group), initially normotensive hyperthyroid cats that develop hypertension after treatment (HT-Post group), and hyperthyroid cats that are normotensive (NT group). Data are presented as median [25th, 75th percentile]. RESULTS: Baseline PRA was not significantly different among the 3 groups (HT-Pre group 1.50 [0.05, 2.37] ng/mL/h, HT-Post group 0.66 [0.17, 2.31] ng/mL/h, NT group 1.11 [0.57, 2.18] ng/mL/h; P = .44). PRA decreased significantly after treatment in the NT group (1.09 [0.53, 2.47] versus 0.22 [0.05, 0.76] ng/mL/h; P < .001) and the HT-Post group (0.71 [0.17, 2.33] versus 0.28 [0.07, 0.57] ng/mL/h; P = .006). Baseline PAC was not significantly different among the 3 groups (HT-Pre group 72.2 [40.0, 145.6] pg/mL, HT-Post group 69.7 [43.3, 142.6] pg/mL, NT group 109.0 [68.2, 184.6] pg/mL; P = .10). PAC decreased significantly after treatment in the NT group (114.4 [56.6, 204.1] versus 59.5 [32.4, 98.2] pg/mL; P < .001) but did not change significantly in the HT-Post group (61.2 [44.9, 124.0] versus 58.4 [42.0, 97.7] pg/mL; P = .59). CONCLUSIONS AND CLINICAL IMPORTANCE: RAAS activation occurs in hyperthyroid cats, but is not associated with the development of hypertension. PAC is not influenced by changes in PRA in hyperthyroid cats that develop hypertension after treatment, perhaps indicating RAAS dysfunction in these cats.
No takes yet. Share an insight, caveat, or question.
Williams et al. (2013) conducted a case-control in Hyperthyroidism with or without hypertension (n=99). Treatment for hyperthyroidism vs. Normotensive hyperthyroid cats was evaluated on Baseline plasma renin activity (PRA) and plasma aldosterone concentration (PAC) (p=0.44). Baseline plasma renin activity (P=0.44) and plasma aldosterone concentration (P=0.10) were not significantly different among hyperthyroid cats with or without concurrent hypertension.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: