Abstract 080: Characterization of Blood Pressure Response to Spironolactone in Patients With Resistant Hypertension using Electronic Medical Records

Abstract

Spironolactone is a recommended add-on therapy for BP control in patients with resistant hypertension (RH). We hypothesized that we could use electronic medical records (EMR) to assess the BP response to the addition of spironolactone in patients with apparent RH who were on a stable anti-hypertensive regimen of at least three antihypertensive medications including a thiazide or dihydropyridine CCB. Patients with RH were identified using a previously published algorithm. We developed an algorithm to identify patients initiated on spironolactone during a period of otherwise stable medication use from up to six months before and after the start of spironolactone to evaluate BP response. We identified 977 RH patients (751 white and 226 black) prescribed spironolactone during a stable medication window. The median dose of spironolactone prescribed was 25 mg and 724 patients were prescribed 25 mg (74.1%). The mean decrease in SBP following spironolactone was 8.5 + 18.1 mmHg and the mean decrease in DBP was 4.0 + 9.9 mmHg, consistent with data from clinical trials. Using a mean decrease in SBP of 5 mmHg or in DBP of 2 mmHg to define “responders,” we found that 29% (283 of 977) of patients were nonresponders. Responders had significantly higher baseline BPs (p<0.001), were older (p=0.04), and had larger decreases in the eGFR (p<0.001) and serum Na + (p<0.004) and larger increases in creatinine (p<0.001) and K + (p<0.001) after starting spironolactone than nonresponders. In blacks, glucose increased following spironolactone in responders compared to non-responders (2.27 + 40.77 vs -15.47 + 62.94 mg/dL, p=0.03); this relationship was not observed in whites. When response was evaluated as a continuous variable, the decrease in SBP and DBP correlated with the decrease in serum Na + (p=0.04) and with the increases in serum K + (p=0.01) and creatinine (p<0.001). In blacks, there was a significant correlation between decrease in SBP and increase in glucose (p=0.04). We have developed an algorithm to assess the BP response to spironolactone in patients with RH using the EMR. Electrolyte changes associated with the BP response to spironolactone are consistent with its mechanism of action to block the mineralocorticoid receptor and decrease activity of the epithelial Na + channel.