Gupta et al published a paper in Hypertension on 1 May 2017 which looked at risk factors for patients not adhering to antihypertensive treatment. High-performance liquid chromatography-tandem mass spectrometry of urine and serum was used to directly and objectively detect non-adherence.

1348 patients were studied in the UK and Czech Republic. The rates of non-adherence in the UK and Czech populations were approximately 42% and 32% respectively. Women were more commonly non-adherent and age was inversely related to non-adherence: every 10 year increase in age showed about a 30% odds reduction for non-adherence.

The greater the number of prescribed medicines for hypertension per patient, the higher the odds for non-adherence (independent of age and sex). Diuretics as a class were associated with the highest likelihood of non-adherence.