Biochemical screening for non-adherence is associated with blood pressure reduction and improvement in adherence

We hypothesised that screening for non-adherence to antihypertensive treatment using liquid chromatography-tandem mass spectrometry based biochemical analysis of urine/serum has therapeutic applications in non-adherent hypertensive patients. A retrospective analysis of hypertensive patients attending specialist tertiary care centres was conducted in two European countries (UK and Czech Republic). Non adherence to antihypertensive treatment was diagnosed using biochemical analysis of urine (UK) or serum (Czech Republic). These results were subsequently discussed with each patient and data on follow-up clinic blood pressure measurements were collected from clinical files. Of 238 UK patients who underwent biochemical urine analysis were non-adherent to antihypertensive treatment. Their initial urinary adherence ratio (the ratio of detected to prescribed antihypertensive medications) increased from 0.33 (0–0.67) to 1 (0.67–1) between the first and the last clinic appointment. The observed increase in the urinary adherence ratio in initially non adherent UK patients was associated with the improved blood pressure control; by the last clinic appointment systolic and diastolic blood pressure were approximately 19.5 mmHg and 7.5 mmHg lower than at baseline (P=0.001 and 0.009, respectively). These findings were further corroborated in 93 non-adherent hypertensive patients from Czech Republic – their average systolic and diastolic blood pressures dropped by approximately 32.6 and 17.4 mmHg (respectively, P<0.001) on appointments following the biochemical analysis. Our data show that non-adherent hypertensive patients respond to based liquid chromatography-tandem mass spectrometry biochemical analysis with improved adherence and significant blood pressure drop. Repeated biochemical analysis should be considered as a therapeutic approach in non-adherent hypertensive patients.