Precise assessment of noncompliance with the antihypertensive therapy in patients with resistant hypertension using toxicological serum analysis.
BACKGROUND
The aim of our study was to assess the prevalence of pseudo-resistance caused by noncompliance with treatment among patients with severe resistant hypertension and to analyze the contributing factors.


METHODS
Three hundred and thirty-nine patients (195 men) with resistant essential hypertension were studied. The first group consisted of 176 patients admitted for hospitalization for exclusion of a secondary cause to our hypertension centre (103 men); the second one consisted of 163 out-patients (92 men) investigated for the first time in an out-patient hypertension clinic. Unplanned blood sampling for assessment of serum antihypertensive drug concentrations by means of liquid chromatography-mass spectrometry was performed in all patients.


RESULTS
Our main finding is a surprisingly low compliance with drug treatment in out-patients with resistant hypertension (23% partially noncompliant and 24% totally noncompliant - in total, 47% prevalence of noncompliance). Eighty-one percent of hospitalized patients were positive, in 10% the results were partially positive and in 9% of the patients, the drugs were all negative. The compliance among hospitalized patients was probably better due to lower numbers of prescribed drugs and expected thorough investigation. More frequently, noncompliance was found in nonworking (potential purpose-built behaviour), younger and less well educated patients. The most frequent noncompliance was to doxazosine, spironolactone and hydrochlorothiazide. We have observed a surprisingly low compliance with treatment among out-patients with severe hypertension.


CONCLUSIONS
We conclude that the evaluation of antihypertensive drugs concentrations is a useful and precise method for assessment of noncompliance in patients with resistant hypertension. This evaluation is useful before starting the diagnostic work-up of secondary forms of hypertension and before assignment patients into protocols with new therapy modalities such as renal denervation.
a3rd Department of Medicine, Department of Endocrinology and Metabolism, Hypertension Center bInstitute of Forensic Medicine and Toxicology, Toxicology Laboratory, General University Hospital, 1st Faculty of Medicine, Charles University, Prague cInstitute for Clinical and Experimental Medicine, Prague d2nd Department of Medicine, General University Hospital, 1st Faculty of Medicine, Charles University, Prague, Czech Republic.
Branislav
B
Strauch
Ondřej
O
Petrák
Tomáš
T
Zelinka
Ján
J
Rosa
Zuzana
Z
Somlóová
Tomáš
T
Indra
Lukáš
L
Chytil
Věra
V
Marešová
Ivana
I
Kurcová
Robert
R
Holaj
Dan
D
Wichterle
Jiří
J
Widimský
D000368:Aged; D000959:Antihypertensive Agents / Q000097:blood / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance
D000959:Antihypertensive Agents