A retrospective, population-based analysis of persistence with antihypertensive drug therapy in primary care practice in Italy

Toward a standard definition and measurement of persistence with drug therapy: Examples from research on statin and antihypertensive utilization

BACKGROUND

Long-term utilization of prescription drugs for chronic conditions such as hypertension and/or hypercholesterolemia is a reality for millions of individuals, yet therapies may be discontinued before they can exert their beneficial effect. Several studies have measured the mean duration of therapy (ie, persistence) using administrative health databases. However, the terminology and methodology used for measuring persistence varied across studies, making it difficult to compare persistence rates.

OBJECTIVES

The objectives of this study were to identify currently used measures of persistence and to propose a standard operational definition for use in administrative database analyses of drug utilization.

METHODS

MEDLINE was searched for English-language articles published between January 1997 and June 2005 that quantified the concepts of persistence, adherence, compliance, or continuity with statin or antihypertensive therapy using administrative prescription claims databases. The conceptual and operational definitions of persistence used in the identified studies were categorized and applied to prescription-refill data for a hypothetical patient to compare the durations of persistence resulting from each method.

RESULTS

Thirty-one articles were identified and reviewed. Few of the studies explicitly stated the conceptual definition of persistence used. Five methods of measuring persistence were identified: anniversary models, minimum-refills models, refill-sequence models, proportion-of-days-covered models, and hybrid models. When these models were applied to data for the hypothetical patient, total persistence with drug therapy ranged from 7 days to >1 year.

CONCLUSIONS

There continue to be inconsistencies in the definition of persistence and the methods by which it is measured. A standard operational definition of persistence should be 2-dimensional, quantifying not only the total duration of therapy, but also the intensity of medication-taking within this interval.

Discontinuation of antihypertensive drugs among newly diagnosed hypertensive patients in UK general practice

OBJECTIVES

To evaluate antihypertensive drug discontinuation among newly diagnosed hypertensive patients.

METHODS

This was a population-based cohort study using the UK General Practice Research Database (GPRD). Patients newly diagnosed with hypertension between 1991 and 2001 and subsequently treated with antihypertensive drugs were included. Overall antihypertensive drug discontinuation was evaluated from a patient's first-ever antihypertensive prescription. Class-specific discontinuations were evaluated from a patient's first-ever prescriptions of angiotensin-converting enzyme (ACE) inhibitors (ACE-I), alpha antagonists, angiotensin-2 antagonists (AIIA), beta blockers, calcium-channel blockers (CCB), miscellaneous, potassium-sparing diuretics, and thiazides. Discontinuation occurred when no antihypertensive prescription was issued within 90 days following the most recent prescription expiration.

RESULTS

The study population comprised 109 454 patients, with 223 228 antihypertensive drug-class episodes contributing to the class-specific analysis. Overall antihypertensive drug discontinuation was 20.3% [95% confidence interval (CI): 20.0, 20.5%] at 6 months and 28.5% (95% CI: 28.2, 28.7%) at 1 year, with a median time to discontinuation of 3.07 years. The median time to antihypertensive class discontinuation was longest for AIIAs (2.90 years) followed by ACE-I (2.24), CCB (1.86), beta blockers (1.50), thiazides (1.50), alpha antagonists (1.35), potassium-sparing diuretics (0.40), and miscellaneous (0.39). One-year discontinuation ranged from 29.4% (95% CI: 28.0, 30.7) for AIIAs to 64.1% (95% CI: 62.1, 66.3) for potassium-sparing diuretics. Forty-four percent who discontinue their first-ever antihypertensive drug class failed to switch to a different drug class within 90 days of discontinuation.

CONCLUSION

It is important that general practitioners (GPs) monitor patients closely in the first year following antihypertensive drug initiation, due to the high early risk of discontinuation, and the low percentage of patients who switch to a different antihypertensive drug class after a drug-class discontinuation. AIIA, followed by ACE-I and CCB, had the lowest risk of discontinuation among antihypertensive drug classes.

Reminder packaging for improving adherence to self-administered long-term medications

BACKGROUND

Current methods of improving medication adherence for health problems are mostly complex, labour-intensive, and not reliably effective. Medication 'reminder packaging' which incorporates a date or time for a medication to be taken in the packaging, can act as a reminder system to improve adherence.

OBJECTIVES

The objective of this review was to determine the effects of reminder packaging to enhance patient adherence with self-administered medications taken for one month or more.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Database of Abstracts of Reviews of Effects (DARE) (The Cochrane Library Issue 3, 2004), MEDLINE, EMBASE, CINAHL and PsycINFO from the start of the databases to 1 September 2004. We also searched the internet, contacted packaging manufacturers, and checked abstracts from the Pharm-line database and reference lists from relevant articles. We did not apply any language restrictions.

SELECTION CRITERIA

We selected randomised controlled trials with at least 80% follow up, comparing a reminder packaging device with no device in participants taking self-administered medications for a minimum of one month.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for inclusion, assessed quality, and extracted data from included studies. Where considered appropriate, data were combined for meta-analysis, or were reported and discussed in a narrative.

MAIN RESULTS

Eight studies containing data on 1,137 participants were included. Six intervention groups in four trials provided data on the percentage of pills taken. Reminder packaging showed a significant increase in the percentage of pills taken, weighted mean difference 11% (95% confidence interval (CI) 6% to 17%). Notable heterogeneity occurred among these trials I(2 )= 96.3%. Two trials provided data for the proportion of self-reported adherent patients, reporting a reduction in the intervention group which was not statistically significant, odds ratio = 0.89 (95% CI 0.56 to 1.40). No appropriate data were available for meta-analysis of different clinical outcomes, the most common of these being blood pressure (three out of eight trials). Other clinical outcomes reported were glycated haemoglobin, serum Vitamin C and E levels, and self-reported psychological symptoms (one trial each).

AUTHORS' CONCLUSIONS

Reminder packing may represent a simple method for improving adherence for patients with selected conditions examined to date. Further research is warranted to improve the design and targeting of these devices.

Differences in antihypertensive drug persistence associated with drug class and gender: a PHARMO study

OBJECTIVE

The objective of the study is to investigate factors related to treatment persistence among users of antihypertensive (AHT) drugs in daily practice.

METHODS

Data for this study were obtained from the PHARMO database including pharmacy records and hospitalizations in the Netherlands (n=950,000). Patients who newly received AHT therapy (n=17,113) between 1997 and 2001 were selected. Of these patients, random samples of 500 patients per drug class were drawn. One-year persistence was defined as (1) the percentage of patients using AHTs at least 270 days and receiving AHT in 3 months after the 1-year follow-up period, and (2) Catalan method (Kaplan-Meier curves). Gender specific persistence rates per drug class were adjusted for significant factors including age, use of antidiabetics and lipid lowering drugs, and prior cardiovascular hospitalizations (OR and 95%CI).

RESULTS

Persistence was highest in users of angiotensin II receptor blockers (ARBs) (62.0%), progressively lower in users of angiotensin converting enzyme inhibitors (ACE-inhibitors, 59.7%), betablockers (35.0%), calcium channel blockers (34.7%), and diuretics (33.0%), resulting in the highest OR of 3.4 [95%CI: 2.6-4.5] for ARBs compared to diuretics. The persistence of AHT use in women was substantially lower (40.1% vs. 50.2%, OR 0.7 [95%CI: 0.6-0.8]) and differences between drug classes were larger than in men.

CONCLUSIONS

These results demonstrate marked differences in persistence between AHT classes, with the highest persistence for ARBs and lowest for diuretics. Women were less persistent with their AHT compared to men. This low persistence leads to suboptimal treatment with a potential for substantial clinical consequences. Especially in women, more attention paid to AHT persistence patterns could improve their cardiovascular outcome.

Racial differences in blood pressure control: potential explanatory factors

PURPOSE

Poor blood pressure control remains a common problem that contributes to significant cardiovascular morbidity and mortality, particularly among African Americans. We explored antihypertensive medication adherence and other factors that may explain racial differences in blood pressure control.

METHODS

Baseline data were obtained from the Veteran's Study to Improve The Control of Hypertension, a randomized controlled trial designed to improve blood pressure control. Clinical, demographic, and psychosocial factors relating to blood pressure control were examined.

RESULTS

A total of 569 patients who were African American (41%) or white (59%) were enrolled in the study. African Americans were more likely to have inadequate baseline blood pressure control than whites (63% vs 50%; odds ratio = 1.70; 95% confidence interval [CI] 1.20-2.41). Among 20 factors related to blood pressure control, African Americans also had a higher odds ratio of being nonadherent to their medication, being more functionally illiterate, and having a family member with hypertension compared with whites. Compared with whites, African Americans also were more likely to perceive high blood pressure as serious and to experience the side effect of increased urination compared with whites. Adjusting for these differences reduced the odds ratio of African Americans having adequate blood pressure control to 1.59 (95% confidence interval 1.09-2.29).

CONCLUSIONS

In this sample of hypertensive patients who have good access to health care and medication benefits, African Americans continued to have lower levels of blood pressure control despite considering more than 20 factors related to blood pressure control. Interventions designed to improve medication adherence need to take race into account. Patients' self-reports of failure to take medications provide an opportunity for clinicians to explore reasons for medication nonadherence, thereby improving adherence and potentially blood pressure control.

Initial treatment of hypertension and adherence to therapy in general practice in Italy

BACKGROUND

Antihypertensive agents are among the most used therapeutic classes. The approach to the pharmacological treatment of hypertension is guided by international recommendations and adherence to treatment is known to result in effective prevention of cardiovascular risk.

AIM

The aim of this study was to evaluate the pattern of use of antihypertensive agents in general practice in terms of drug choice for the initial treatment of hypertension and adherence to treatments among newly recruited patients.

METHODS

We collected the data of all antihypertensive drugs prescribed by general practitioners (GPs) and reimbursed between January 1998 and December 2002 by a Local Health Authority of Emilia Romagna (Ravenna district, 350,000 inhabitants). We selected subjects aged 40 years and older, permanently living in the area during the whole period of the study, who received their first prescription of antihypertensives between January and December 1999, with no prescription of antihypertensive agents in the previous year. For each patient, we documented the starting regimen and evaluated adherence to treatment in terms of persistence during the years (patients were defined persistent if they received at least one prescription per year) and in terms of daily coverage (patients were defined covered if they received an amount of drugs consistent with a daily treatment). Finally, switches or addition of other therapeutic classes during the 3-year period were identified.

RESULTS

A cohort of 6,043 subjects receiving their first antihypertensive treatment in 1999 was obtained. Regarding the starting regimen, monotherapies with angiotensin converting enzyme inhibitors (n = 1,597; 26%) or calcium channel blockers (n = 1126; 19%) were the most frequently prescribed. Of the patients, 21% started with a drug combination regimen. Regarding adherence to treatment, 18% of the cohort received only one prescription throughout the 3 years, 13% received more than one prescription but stopped the therapy during the first year, 69% were persistent during the second year and 60% also during the third year. Only 34% were covered during the first year and 24% also during the second year, whereas only 20% of the patients resulted covered throughout the 3 years. Among persistent patients, 41% maintained the same antihypertensive regimen throughout the 3 years, 25% added other drugs to the initial treatment and 34% switched to completely different regimens.

CONCLUSIONS

Our findings reflect the lack of convergence among guidelines on the drug class(es) to be considered as first choice in the initial treatment of hypertension. Although an intervention in this field may have important implications in terms of cost savings, the ongoing debate does not allow us to draw definite conclusions on whether measures should be taken by the National Health Authority. However, the lack of adherence to antihypertensive treatment is undoubtedly a matter of concern for public health and should be addressed with appropriate interventions.

Is interview a reliable method to verify the compliance with antihypertensive therapy? An international central-European study

BACKGROUND

Non-compliance with prescribed antihypertensive medication is an important contributor to the failure of antihypertensive therapy.

OBJECTIVE

To assess the validity of a short questionnaire in the identification of non-compliant patients.

METHODS

In three central-European countries, work-site screening for hypertension was conducted. Blood pressure was measured using an automatic electronic blood pressure measuring device (BpTRU). Respondents were interviewed by trained personnel and a short questionnaire focused on blood pressure awareness and treatment compliance was completed.

RESULTS

A total of 2812 persons were screened: 841(29.9%) respondents were hypertensive, and out of these the total number of treated hypertensive subjects was 359 (42.6%). Mean systolic blood pressure and diastolic blood pressure were significantly lower in the compliant group than the non-compliant group (systolic blood pressure, 139.4 and 146.2 mmHg, respectively, P = 0.002; and diastolic blood pressure, 89.2 and 92.3 mmHg, respectively, P < 0.01). The non-compliant group was younger than the compliant group (mean age, 46.7 versus 48.9 years, respectively, P = 0.01). Females, patients on combined therapy and non-smokers were more compliant than males, those on mono-therapy and smokers (P = 0.01, P = 0.004 and P = 0.005, respectively).

CONCLUSION

Patients reporting strict compliance with prescribed drug therapy have significantly lower systolic blood pressure and diastolic blood pressure than those who admit even an occasional lapse in taking medication. A properly formulated questionnaire can identify non-compliant patients.

Compliance and persistency in glaucoma follow-up treatment

PURPOSE OF REVIEW

To summarize research published between 1980 and October 2004 regarding compliance (the extent to which patients' behaviors correspond with providers' recommendations) and persistency (total time on therapy) in patients diagnosed with open-angle glaucoma or ocular hypertension; to suggest approaches ophthalmologists might consider to improve compliance and persistency; and to identify areas warranting future research.

RECENT FINDINGS

Medication compliance, the focus of most compliance-related research, has been measured using a variety of methods including patient self-reports, the medication possession ratio, and electronic monitoring. Noncompliance rates of at least 25% commonly have been reported. The primary obstacles to medication compliance appear to be situational/environmental (e.g., being away from home or a change in routine) or related to the medication regimen (e.g., side effects or complexity). Persistency with ocular hypotensive therapies has been found to be poor. Retrospective cohort studies using survival analyses have reported that fewer than 25% of patients are persistent over 12 months.

SUMMARY

Accurately assessing patient compliance and persistency is important to optimizing patient care. Physicians may mistake either medication noncompliance or lack of persistency with poor efficacy. Such errors would likely increase health care costs if they result in unnecessary changes to a patient's therapeutic regimen or in surgery.

Persistence and discontinuation patterns of antihypertensive therapy among newly treated patients: a population-based study

The objective was to assess persistence with antihypertensive therapy (AHT) and discontinuation patterns in patients newly dispensed different antihypertensive drug classes in a natural Canadian population-based setting. Hypertensive patients initiating AHT monotherapy were included in this 3-year retrospective cohort study (N=21 326) using the Saskatchewan health-care databases. Persistence was defined as consistently refilling a new prescription for AHT within 90 days of a previous dispensing. New courses of AHT were also documented in nonpersistent patients. Kaplan-Meier and Cox regression analyses were used to compare persistence and new courses of therapy across initial drugs. Compared to the newer angiotensin II antagonists (AIIAs), the likelihood of discontinuing therapy over the 39-month study period was significantly higher for angiotensin-converting enzymes inhibitors (HR=1.29; 95% CI=1.16-1.43), calcium channel blockers (HR=1.42; 95% CI=1.27-1.60), beta blockers (HR=1.62; 95% CI=1.45-1.80) and diuretics (HR=1.92; 95% CI=1.73-2.14). In the year following treatment discontinuation, between 54 and 75% of patients initiated a second course of treatment. Patients initiated on an AIIA had a significantly higher likelihood of starting a new course of therapy after a first treatment discontinuation, compared to all other agents. In conclusion, hypertensive patients initiated on an AIIA not only had greater persistence to AHT but were also more likely to initiate a new course of AHT after discontinuation than those initiating treatment with other agents. Further studies are required that relate intermittent treatment behaviours to health outcomes and costs in hypertension.

Pharmacoeconomics of antihypertensive drug treatment: an analysis of how long patients remain on various antihypertensive therapies

The objective of the research was to perform a clinical practice-based analysis of how long patients remain on various antihypertensive drugs. An administrative database listing of patient baseline characteristics, drug prescriptions, and hospital admissions was used. All new users of antihypertensive drugs, > or =20 years of age, receiving a first prescription for diuretics, beta blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, or angiotensin II receptor antagonists between January 1, 2000, and December 31, 2000, were included and observed for 365 days. Persistence was defined as a duration of therapy <273 days. A total of 14,062 patients were included in the study, 39.7% of whom remained on treatment (persistent patients). Persistent patients were more likely to be older, taking other drugs for concurrent disorders, hospitalized for cardiovascular diseases, and initially prescribed angiotensin II receptor antagonists. Persistent patients accounted for 80.6% of the overall cost for antihypertensive drugs. Factors associated with drug cost were age, pattern of persistence, number of prescribed classes, and specific medication at enrollment. Measuring persistence with treatment is needed to evaluate the appropriateness and the cost-effectiveness of drug use.

Pharmacoeconomic burden of undertreating hypertension

Many studies have shown the importance of antihypertensive drug therapy as a factor in reducing the risk of cardiovascular morbidity and mortality, and in containing the cost of managing hypertension and its complications. Nevertheless, the evidence in clinical practice indicates about half of hypertensive patients do not receive pharmacological treatment and about half of treated patients do not achieve blood pressure level control. Undertreating hypertension is the leading cause of failure in drug therapy effectiveness and cost effectiveness. The pharmacoeconomic burden of undertreating hypertension can be defined as the clinical (number of cardiovascular events) and economic (costs of managing cardiovascular events) consequences that would have been avoided by adequate control of blood pressure levels. In the last few years, the increase in this burden and the restriction of budget constraints has raised the awareness of healthcare providers with regards to the need to achieve better performance and to improve disease management of hypertension. This review aims to present the current situation regarding the pharmacoeconomic burden of undertreating hypertension by identifying the key issues of this medical condition, defining and measuring the extent of undertreatment, defining and measuring costs associated with undertreatment, and discussing some fundamental aspects of disease management for hypertension. The pharmacoeconomic burden of undertreating hypertension appears to be an extremely important phenomenon for which there is currently only very limited adequate research. The present dearth of appropriate data can be largely attributed to the lack of epidemiological studies in clinical practice. Future studies are necessary for a more precise quantification of the therapeutic and economic impact of undertreating arterial hypertension in clinical practice (appropriateness studies) and for more precise selection of antihypertensive drugs on the basis of the different cost-effectiveness profiles detected in 'real world' settings (cost-effectiveness studies).

Patient persistency with topical ocular hypotensive therapy in a managed care population

PURPOSE

To evaluate persistency with topical ocular hypotensive therapies in patients new to pharmacological management of elevated intraocular pressure (IOP).

DESIGN

Retrospective, cohort study; Protocare Sciences managed care database; approximately 3 million members in commercial health maintenance organizations and preferred provider organizations and in Medicare risk plans.

METHODS

Patients were at least 20 years of age initiating therapy between July 1, 1996, and June 30, 2002, with betaxolol, bimatoprost, brimonidine, dorzolamide, latanoprost, timolol, or travoprost as monotherapy. Patients must have been continuously enrolled and not have received glaucoma surgery in the 180 days before the index prescription fill. Prescription refill records for all ocular hypotensive drugs were extracted through June 30, 2002. Outcome measures were (1) discontinuation of index drug, and (2) either discontinuation or change in index drug. Changing therapy was defined as switching to or adding another ocular hypotensive. Rates of discontinuation and discontinuation/change were compared using Cox regression models.

RESULTS

In all, 28,741 patients met the inclusion criteria. Compared with latanoprost, those treated with other drugs were from 37% (timolol) to 72% (bimatoprost) more likely to discontinue and from 20% (timolol) to 58% (dorzolamide) more likely to discontinue/change therapy (P <.001 for all comparisons). At 12 months, 33% of patients treated with latanoprost and 19% of those receiving other ocular hypotensives had not discontinued therapy; 23% and 13%, respectively, had not discontinued or changed therapy. Compared with latanoprost, significantly higher percentages of patients treated with each alternate agent had only one fill of their index drugs (P <.001).

CONCLUSIONS

Although persistency rates were low across agents, latanoprost-treated patients demonstrated significantly greater persistency than did those treated with other topical ocular hypotensive therapies.

Medicine partnerships

Partial medication compliance, where patients do not take enough of their prescribed medicine to achieve adequate outcomes, is common. Research using electronic monitoring to assess compliance has shown that people take approximately 75% of doses as prescribed, irrespective of the condition being treated or its severity. Erratic compliance often leads to discontinuation of therapy, as treatment is perceived to be ineffective. Compliance decreases as frequency of dosing increases. Inadequate compliance and treatment persistence results in poor outcomes, despite the best efforts of the medical team. It is important to develop and implement a strategy to improve compliance. Simple steps that can be taken include helping patients to select "cues" to remind them to take their tablets, use of dose reminder boxes, and visual feedback of compliance data from electronic monitors.

Secondary prevention of stroke in Italy: a cross-sectional survey in family practice

BACKGROUND

Hypertension control and antiplatelet or oral anticoagulant drugs are the basis for secondary prevention of cerebrovascular events. Family physicians (FPs) are usually involved in both aspects of prevention, but no research has been carried out in Italy to evaluate the behavior of FPs in this field of prevention.

METHODS

Data concerning 318 Italian FPs and 465,061 patients were extracted from the Health Search Database. Patients with coded diagnoses of stroke and transient ischemic attack (TIA) were selected. Demographic records and information regarding presence of concurrent disease and medical records were also obtained. Logistic regression analyses were carried out to assess whether conditions exist that make appropriate control of blood pressure (BP) and prescription of antiplatelet or anticoagulant drugs more likely.

RESULTS

We selected 2555 patients with diagnosis of stroke and 2755 with TIA. Among all of the subjects, 32.6% had no BP recorded. Among the remaining subjects, 58.7% reported uncontrolled BP. Isolated systolic hypertension has been shown in 68.8% of patients with uncontrolled BP. Antiplatelet and anticoagulant drugs were prescribed in 72% of these cases. Factors that made the prescription significantly more unlikely were diagnosis of TIA (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.41 to 0.54), total invalidity (OR, 0.66; 95% CI 0.56 to 0.78), and time from event of 5 years or more (OR, 0.81; 95% CI, 0.70 to 0.94).

CONCLUSIONS

Italian FPs could improve secondary prevention of cerebrovascular accidents. The primary target of intervention should be the control of systolic BP, and the group of patients with unacceptably high BP should be given priority. All of these patients should have been prescribed antiplatelet drugs or anticoagulant agents, except in cases of extremely short life expectancy or substantial contraindications.