Medication adherence during laboratory workup for primary aldosteronism: pilot study

Abstract

PurposeCurrent hypertension guidelines stipulate that all incompatible medications be stopped before performing laboratory screening for aldosteronism, but patient adherence is unclear. We measured plasma drug concentrations to determine drug adherence and potential drug bias during biochemical tests.Patients and methodsPlasma concentrations of 10 antihypertensive drugs were quantified by mass spectrometry in 24 consecutive ambulatory patients with uncontrolled hypertension routinely evaluated for aldosteronism. Drug screening was done before (first visit), and on the day of biochemical tests (second visit) after stopping all incompatible medications. Concentrations above those expected at trough dosing interval defined same-day dose intake.ResultsOn the first and second visits, 76% vs 77% of prescribed antihypertensive doses could be verified in plasma. A total of 33% of patients were found to be nonadherent and showed divergent plasma drug results relative to prescriptions (21% drugs not detected/13% unprescribed drugs found) on first visit, 25% on the second (0%/25%), and 46% for both. A total of 21% used medication incompatible with the biochemical tests on the second visit. Moreover, 17% of drug concentrations were below expected trough levels on the first vs 15% on the second visit. This analysis revealed additional four (17%) vs three (13%) nonadherent patients who failed same-day dose intake and remained undetected by qualitative drug tests.ConclusionNonadherence was frequent during laboratory evaluations for aldosteronism advocating cautious interpretation of results. A multicenter study is desirable to set the stage for new screening protocols that should incorporate also incentives and checks of drug adherence.

Primary aldosteronism – the expanding spectrum of unsolved practical issues

“…However, the problematic issue is the accurate knowledge about the medications patients are taking. The pilot study by Sandbaumhuter et al illustrates very poor adherence to prescribed therapy as 33% of patients were having plasma drug results different from the preconceived (55). That may lead to mistakes while interpreting ARR in accordance to medications' influence on hormone levels if we do not discuss this matter very carefully with the patient.…”

Nonadherence in Hypertension: How to Develop and Implement Chemical Adherence Testing

“…33 Another study found unexpected (unprescribed) use of β-adrenoreceptor and renin-angiotensin-aldosterone system blockers in 25% of hypertensive patients. 34 Those patients may be receiving BP-lowering agents such as beta-blockers or RAS-blockers prescribed for cardiovascular disease protection (or postmyocardial infarction) rather than for BP-lowering per se.…”

“…Blood is less often used for qualitative analysis in adherence testing [51][52][53] but is more frequently used for quantification. 34,45,[54][55][56][57][58] Certain groups have started quantifying antihypertensive drugs and comparing the results against the established peak (C max ) and minimal/trough (C min ) plasma drug concentrations. 45,54,57,59 These may provide a putative range indicative of regular intake (below steady-state range in Figure 2).…”