Nonadherence to antihypertensive medications is related to pill burden in apparent treatment-resistant hypertensive individuals.

OBJECTIVE: Nonadherence to medication is present in at least 50% of patients with apparent treatment-resistant hypertension. We examined the factors associated with nonadherence as detected by a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based urine antihypertensive drug assay. METHODS: All urine antihypertensive test results, carried out for uncontrolled hypertension (BP persistently >140/90 mmHg) between January 2015 and December 2016 at a single toxicology laboratory were analysed. Drugs detected were compared with the antihypertensive drugs prescribed. Patients were classified as adherent (all drugs detected), partially nonadherent (at least one prescribed drug detected) or completely nonadherent (no drugs detected). Demographic and clinical parameters were compared between the adherent and nonadherent groups. Binary logistic regression analysis was performed to determine association between nonadherence and demographic and clinical factors. RESULTS: Data on 300 patients from nine hypertension centres across the United Kingdom were analysed. The median age was 59 years, 47% women, 71% Caucasian, median clinic BP was 176/95 mmHg and the median number of antihypertensive drugs prescribed was four. One hundred and sixty-six (55%) were nonadherent to prescribed medication with 20% of these being completely nonadherent. Nonadherence to antihypertensive medication was independently associated with younger age, female sex, number of antihypertensive drugs prescribed, total number of all medications prescribed (total pill burden) and prescription of a calcium channel blocker. CONCLUSION: This LC-MS/MS urine analysis-based study suggests the majority of patients with apparent treatment-resistant hypertension are nonadherent to prescribed treatment. Factors that are associated with nonadherence, particularly pill burden, should be taken into account while treating these patients.

Medication adherence and treatment-resistant hypertension: a review.

Nonadherence is a common reason for treatment failure and treatment resistance. No matter how it is defined, it is a major issue in the management of chronic illnesses. There are numerous methods to assess adherence, each with its own strengths and weaknesses; however, no single method is considered the best. Nonadherence is common in patients with hypertension, and it is present in a large proportion of patients with uncontrolled blood pressure taking three or more antihypertensive agents. Availability of procedure-based treatment options for these patients has shed further light on this important issue with development of new methods to assess adherence. There is, however, no consensus on the management of nonadherence, which reflects the complex interplay of factors responsible for it.

Renal denervation using carbon dioxide renal angiography in patients with uncontrolled hypertension and moderate to severe chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is the most common cause of secondary hypertension. More than half of the patients have uncontrolled hypertension (≥140/90 mmHg on three or more antihypertensive agents at optimum doses). Renal sympathetic denervation (RSDN) has been shown to reduce blood pressure (BP) in patients with resistant hypertension. Although patients with CKD have high sympathetic drive, all major clinical trials have excluded patients with estimated glomerular filtration rates (eGFRs) <45 mL/min/1.73m2 for risk of contrast-induced nephropathy. METHODS: In this pilot study, carbon dioxide (CO2) was used as the sole contrast agent to carry out renal angiography and RSDN in patients with moderate to severe CKD (eGFR 15-44 mL/min/1.73m2) and uncontrolled hypertension. RESULTS: Eleven patients (eight males) underwent RSDN. The median age was 57 years [interquartile range (IQR) 49-66]. The median number of antihypertensives being taken at baseline was 4 (IQR 3-4). No statistically significant difference was observed in serum creatinine in the serial follow-ups until at 6 months[median difference 0.25 mg/dL (IQR 0.09-0.53); P = 0.008]. There was a non-significant reduction in median clinic BP from baseline to 6 months [-14 mmHg (IQR -24-5)] and a significant increase in daytime ambulatory systolic BP [7 mmHg (IQR -2-12); P= 0.045]. A trend towards a serial reduction in albuminuria was observed. Procedure-related complications included a groin haematoma (n = 1) and reported flank (n = 1) and groin pain (n = 1). CONCLUSIONS: This pilot study shows that CO2 renal angiography can be used to perform RSDN in patients with significant renal impairment and may lead to associated improvements in clinic BP and albuminuria.

Renal Denervation.

Sympathetic nervous system over-activity is closely linked with elevation of systemic blood pressure. Both animal and human studies suggest renal sympathetic nerves play an important role in this respect. Historically, modulation of sympathetic activity has been used to treat hypertension. More recently, catheter based renal sympathetic denervation was introduced for the management of treatment resistant hypertension. Sound physiological principles and surgical precedent underpin renal denervation as a therapy for treatment of resistant hypertension. Encouraging results of early studies led to a widespread adoption of the procedure for management of this condition. Subsequently a sham controlled randomised controlled study failed to confirm the benefit of renal denervation leading to a halt in its use in most countries in the world. However, critical analysis of the sham-controlled study indicates a number of flaws. A number of lessons have been learnt from this and other studies which need to be applied in future trials to ascertain the actual role of renal denervation in the management of treatment resistant hypertension before further implementation. This chapter deals with all these issues in detail.

Renal Denervation in Patients With Uncontrolled Hypertension and Confirmed Adherence to Antihypertensive Medications.

Renal denervation (RDN) has emerged as a potential device-based treatment for resistant hypertension. The authors present their experience of the use of catheter-based RDN as part of routine clinical care in two specialist hypertension clinics. Thirty-four patients with uncontrolled hypertension underwent RDN. All patients had ambulatory blood pressure (BP) monitoring and directly observed medication administration prior to the procedure to exclude white-coat hypertension and nonadherence, respectively. Overall, there was a significant change in clinic systolic BP of -15.1 mm Hg (95% confidence interval, -23.4 to -6.8; P=.001) and clinic diastolic BP of -6.2 mm Hg (95% confidence interval, -11.5 to -0.9; P=.02) 6 months postprocedure, and a nonsignificant change in daytime ambulatory BP of -5.4/-2.9 mm Hg. Eighteen patients (51.4%) showed a significant reduction in their clinic systolic BP (≥10 mm Hg) and 16 (47%) had a significant reduction in their daytime ambulatory systolic BP (≥5 mm Hg) at 6 months.