Direct assessment of adherence and drug interactions in patients with hypertensive crisis-A cross-sectional study in the Emergency Department

Abstract

Though drug adherence is supposed to be low in hypertensive crisis (HTN-C), there are no data available from direct adherence assessments. The aim of the present study was to evaluate adherence to prescribed antihypertensives and potential interactions of concomitant drugs and foods with prescribed antihypertensives in patients with HTN-C by a direct evaluation via biochemical urine analysis. In the present cross-sectional study, 100 patients with HTN-C, admitted to the emergency department (ED), were included. A biochemical urine analysis using gas chromatography-tandem mass spectrometry was performed. Out of 100 patients, 86 received antihypertensives. Urine analyses could be evaluated unambiguously in 62 patients. In 15 of these 62 patients (24%), a nonadherence could be demonstrated, and in 21 patients (34%), a partial nonadherence could be demonstrated. Patients with nonadherence or partial nonadherence showed a longer hypertension history (15[5-22] vs 10[3-15] years, P = 0.04) were prescribed more general medication (number 7.1 ± 3.4 vs 3.4 ± 1.8; P < 0.01) as well as antihypertensive drugs (number 2.8 ± 1.1 vs 1.5 ± 0.7, P < 0.01). A potential BP-raising trigger by medications or food interaction was frequently detectable, predominantly with nonsteroidal anti-inflammatory drugs (NSAIDs; n = 38), glucocorticoids (n = 8), antidepressants (n = 10), and licorice (n = 10). Nonadherence and partial nonadherence to prescribed antihypertensives might play a crucial role for the occurrence of HTN-C. However, further case-controlled studies are needed to confirm the present findings. Ingestion of concurrent over-the-counter drugs such as NSAIDs but also prescribed drugs as well as aliments may lead to critical BP elevation. In order to prevent HTN-C, the present findings emphasize the importance for clinicians to pay attention to the issue of adherence and co-medication.

Keywords: adherence; drugs; emergency medicine; hypertension; hypertensive crisis; hypertensive emergency; mass spectroscopy.

Figure 1

Flowchart. Adherence uncertainly assessable: permanent antihypertensive medication was applied in the emergency department prior to urine asservation

Figure 2

Distribution of adherence level according to the percentage of medication detected. A, Degree of adherence in patients detected by mass spectrometry urine analysis. Percentage of prescribed drugs taken by patients. B, Degree of adherence regarding the particular antihypertensive classes (in percent of patients). ACEi: ACE‐inhibitors; ARB: Angiotensin receptor blocker; CCB: calcium channel blocker