Different aspects of adherence to antihypertensive treatments

Trends in Prescription and Determinants of Persistence to Antihypertensive Therapy : The PAPEETE Study

OBJECTIVES

To assess trends in prescriptions, determinants and timing of treatment discontinuation and/or changes in antihypertensive drug therapy in a cohort of hypertensive patients living in Pavia, a city in the north of Italy.

METHODS

The cohort included 61 493 patients aged ≥18 years who received their first antihypertensive drug prescription (monotherapy, fixed or extemporaneous combination) during the period 2003-6. Patients were classified as 'persistent' if 12 months after the beginning of treatment they were still taking a regular therapy (same drug = 'same therapy users', added one or more drugs = 'add-on therapy users', different drug = 'switchers'). Otherwise, they were classified as 'non-persistent' (stopping therapy after the first prescription = 'occasional users'; stopping treatment early = 'stoppers'; taking medicines in an erratic fashion = 'intermittent users').

RESULTS

ACE inhibitors were the most frequently prescribed drugs (22.8%), followed by β-adrenoceptor antagonists (β-blockers) [14.3%], diuretics (13.9%), Ca(2+) antagonists (11.4%) and angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) [9.3%]. After 12 months, persistent patients were only 11.2% (same therapy users 6.7%, switchers 3.2%, add-on therapy users 1.3%). Non-persistent patients were 88.8% (35.3% occasional users, 20.6% stoppers, 32.8% intermittent users). Patient-related predictors of persistence were older age, male sex, concomitant treatment with antidiabetic and hypolipidaemic drugs and previous hospitalizations for cardiovascular events. Highest level of persistence was seen in patients starting with ARBs (18.8%), followed by ACE inhibitors (11.4%), β-blockers (11.0%), Ca(2+) antagonists (10.8%) and diuretics (3.0%). Among ARBs, considering separately monotherapy and fixed-combination therapy, highest level of persistence was observed in patients starting with candesartan, irbesartan, valsartan and telmisartan given in monotherapy, and with valsartan and telmisartan given in fixed-dose combination.

CONCLUSIONS

Persistence to antihypertensive treatment at 12 months is only 11.2%, being the lowest with diuretics (3.0%) and the highest with ARBs (18.8%).

A new taxonomy for describing and defining adherence to medications

Interest in patient adherence has increased in recent years, with a growing literature that shows the pervasiveness of poor adherence to appropriately prescribed medications. However, four decades of adherence research has not resulted in uniformity in the terminology used to describe deviations from prescribed therapies. The aim of this review was to propose a new taxonomy, in which adherence to medications is conceptualized, based on behavioural and pharmacological science, and which will support quantifiable parameters. A systematic literature review was performed using MEDLINE, EMBASE, CINAHL, the Cochrane Library and PsycINFO from database inception to 1 April 2009. The objective was to identify the different conceptual approaches to adherence research. Definitions were analyzed according to time and methodological perspectives. A taxonomic approach was subsequently derived, evaluated and discussed with international experts. More than 10 different terms describing medication-taking behaviour were identified through the literature review, often with differing meanings. The conceptual foundation for a new, transparent taxonomy relies on three elements, which make a clear distinction between processes that describe actions through established routines ('Adherence to medications', 'Management of adherence') and the discipline that studies those processes ('Adherence-related sciences'). 'Adherence to medications' is the process by which patients take their medication as prescribed, further divided into three quantifiable phases: 'Initiation', 'Implementation' and 'Discontinuation'. In response to the proliferation of ambiguous or unquantifiable terms in the literature on medication adherence, this research has resulted in a new conceptual foundation for a transparent taxonomy. The terms and definitions are focused on promoting consistency and quantification in terminology and methods to aid in the conduct, analysis and interpretation of scientific studies of medication adherence.

A new taxonomy for describing and defining adherence to medications

Interest in patient adherence has increased in recent years, with a growing literature that shows the pervasiveness of poor adherence to appropriately prescribed medications. However, four decades of adherence research has not resulted in uniformity in the terminology used to describe deviations from prescribed therapies. The aim of this review was to propose a new taxonomy, in which adherence to medications is conceptualized, based on behavioural and pharmacological science, and which will support quantifiable parameters. A systematic literature review was performed using MEDLINE, EMBASE, CINAHL, the Cochrane Library and PsycINFO from database inception to 1 April 2009. The objective was to identify the different conceptual approaches to adherence research. Definitions were analyzed according to time and methodological perspectives. A taxonomic approach was subsequently derived, evaluated and discussed with international experts. More than 10 different terms describing medication-taking behaviour were identified through the literature review, often with differing meanings. The conceptual foundation for a new, transparent taxonomy relies on three elements, which make a clear distinction between processes that describe actions through established routines ('Adherence to medications', 'Management of adherence') and the discipline that studies those processes ('Adherence-related sciences'). 'Adherence to medications' is the process by which patients take their medication as prescribed, further divided into three quantifiable phases: 'Initiation', 'Implementation' and 'Discontinuation'. In response to the proliferation of ambiguous or unquantifiable terms in the literature on medication adherence, this research has resulted in a new conceptual foundation for a transparent taxonomy. The terms and definitions are focused on promoting consistency and quantification in terminology and methods to aid in the conduct, analysis and interpretation of scientific studies of medication adherence.

Choices, persistence and adherence to antihypertensive agents: evidence from RAMQ data

BACKGROUND

Most treatment recommendations for hypertension are based on criteria that consider efficacy, safety and cost. Given the need for long-term use of antihypertensive agents, treatment compliance should also be taken into consideration in the selection process.

OBJECTIVE

The purpose of the present study was to estimate persistence and adherence to antihypertensive agents in a real-life setting.

METHODS

Persistence and adherence to treatment were estimated using data from the Regie de l'assurance maladie du Quebec.

RESULTS

Data from a random sample of 4561 subjects with a diagnosis of hypertension covered by the Regie de l'assurance maladie du Quebec drug plan and using one of the antihypertensive agents reimbursed by the drug plan for the first time between January 2000 and December 2001 were analyzed. The persistence rate observed after a two-year period with diuretics was significantly lower (52.8%) than with any other classes of antihypertensive agent (P<0.01). Persistence rates for beta-blockers, calcium channel blockers, angiotensin-II receptor blockers and angiotensin-I converting enzyme inhibitors were 69.3%, 64.3%, 60.9% and 58.9%, respectively. After two years, the proportion of patients who were 80% adherent to their treatment was 64.9% for angiotensin-I converting enzyme inhibitors, 65.0% for angiotensin-II receptor blockers, 64.2% for calcium channel blockers, 60.3% for beta-blockers and 50.9% for diuretics. The proportion of patients who were 80% adherent to their treatment was significantly lower for diuretics than with any other antihypertensive agents (P<0.01).

CONCLUSION

Persistence and adherence to treatment are essential to treatment success. Results of the present study indicate that, in a real-life setting, patients are significantly less compliant to diuretics than to any other antihypertensive agents.