Canadian provincial trends in antihypertensive drug prescriptions between 1996 and 2006

Trends in antihypertensive drug utilization in British Columbia, 2004-2019: a descriptive study

BACKGROUND

Clinical guidelines for hypertension were updated with lower blood pressure targets following new studies in 2015; the real-world impact of these changes on antihypertensive drug use is unknown. We aimed to describe trends in antihypertensive drug utilization from 2004 to 2019 in British Columbia.

METHODS

We conducted a longitudinal study to describe the annual prevalence and incidence rate of use of 5 antihypertensive drug classes (thiazides, angiotensin-converting enzyme [ACE] inhibitors, angiotensin II receptor blockers [ARBs], calcium channel blockers and β-blockers) among BC residents aged 30-75 years. We also conducted a cohort study to compare the risk of discontinuation and switch or add-on therapy between incident users of the above drug classes. We used linkable administrative health databases from BC. We performed a Fine-Gray competing risk analysis to estimate subhazard ratios.

RESULTS

Among BC residents aged 30-75 years (population: 2 376 282 [2004] to 3 014 273 [2019]), the incidence rate of antihypertensive drug use decreased from 23.7 per 1000 person-years in 2004 to 18.3 per 1000 person-years in 2014, and subsequently increased to 22.6 per 1000 person-years in 2019. The incidence rate of thiazide use decreased from 8.9 per 1000 person-years in 2004 to 3.2 per 1000 person-years in 2019, and incidence rates for the other drug classes increased. Incident users receiving thiazide monotherapy had an increased risk of discontinuing any antihypertensive treatment compared with ACE inhibitor monotherapy (subhazard ratio 0.96, 95% confidence interval [CI] 0.95-0.97), ARB monotherapy (subhazard ratio 0.84, 95% CI 0.81-0.87) and thiazide combination with ACE inhibitor or ARB (subhazard ratio 0.86, 95% CI 0.84-0.88), and had the highest risk of switching or adding on.

INTERPRETATION

First-line use of thiazides continued to decrease despite a marked increase in incident antihypertensive therapy following updated guidelines; incident users receiving ARB monotherapy were least likely to discontinue, and incident users receiving thiazide monotherapy were more likely to switch or add on than users of other initial monotherapy or combination. Further research is needed on the factors influencing treatment decisions to understand the differences in trends and patterns of antihypertensive drug use.

Antihypertensive Prescribing for Uncomplicated, Incident Hypertension: Opportunities for Cost Savings

Background

A range of first-line similarly effective medications ranging in price are recommended for treating uncomplicated hypertension. Considering drug costs alone, thiazides and thiazide-like diuretics are the most cost-efficient option. We determined incident prescribing of thiazides for newly diagnosed hypertension as first-line treatment in Alberta, factors that predicted receiving thiazides vs more costly medications, and how much could be saved if more patients were prescribed thiazides.

Methods

Using a retrospective cohort design, factors predicting receiving thiazides vs other agents were determined using mixed effects logistic regression. Cost savings were simulated by shifting patients from other antihypertensive medications to thiazides and calculating the difference.

Results

Within our cohort of 89,548 adults, only 12% received thiazides as first-line treatment whereas 44% received angiotensin converting enzyme inhibitors, 17% received angiotensin receptor blockers, 16% received calcium channel blockers, and 10% received β-blockers. Antihypertensive medications were typically prescribed by office-based, general practitioners (88%). Being male and receiving a prescription from a physician with ≥ 20 years of practice and a high clinical workload were associated with increased odds of receiving nonthiazides. In the extreme case that all patients received thiazides as their first prescription, spending would have been reduced by a maximum of 95% (CAD$1.8 million).

Conclusions

Only 12% of Albertan adults with incident, uncomplicated hypertension were prescribed thiazides as first-line treatment. With the opportunity for drug cost savings, future research should evaluate the risk of adverse events and side effects across the drug classes and whether the costs associated with managing those risks could offset the savings achieved through increased thiazide use.

Worldwide trends in blood pressure from 1975 to 2015: a pooled analysis of 1479 population-based measurement studies with 19·1 million participants

BACKGROUND

Raised blood pressure is an important risk factor for cardiovascular diseases and chronic kidney disease. We estimated worldwide trends in mean systolic and mean diastolic blood pressure, and the prevalence of, and number of people with, raised blood pressure, defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher.

METHODS

For this analysis, we pooled national, subnational, or community population-based studies that had measured blood pressure in adults aged 18 years and older. We used a Bayesian hierarchical model to estimate trends from 1975 to 2015 in mean systolic and mean diastolic blood pressure, and the prevalence of raised blood pressure for 200 countries. We calculated the contributions of changes in prevalence versus population growth and ageing to the increase in the number of adults with raised blood pressure.

FINDINGS

We pooled 1479 studies that had measured the blood pressures of 19·1 million adults. Global age-standardised mean systolic blood pressure in 2015 was 127·0 mm Hg (95% credible interval 125·7-128·3) in men and 122·3 mm Hg (121·0-123·6) in women; age-standardised mean diastolic blood pressure was 78·7 mm Hg (77·9-79·5) for men and 76·7 mm Hg (75·9-77·6) for women. Global age-standardised prevalence of raised blood pressure was 24·1% (21·4-27·1) in men and 20·1% (17·8-22·5) in women in 2015. Mean systolic and mean diastolic blood pressure decreased substantially from 1975 to 2015 in high-income western and Asia Pacific countries, moving these countries from having some of the highest worldwide blood pressure in 1975 to the lowest in 2015. Mean blood pressure also decreased in women in central and eastern Europe, Latin America and the Caribbean, and, more recently, central Asia, Middle East, and north Africa, but the estimated trends in these super-regions had larger uncertainty than in high-income super-regions. By contrast, mean blood pressure might have increased in east and southeast Asia, south Asia, Oceania, and sub-Saharan Africa. In 2015, central and eastern Europe, sub-Saharan Africa, and south Asia had the highest blood pressure levels. Prevalence of raised blood pressure decreased in high-income and some middle-income countries; it remained unchanged elsewhere. The number of adults with raised blood pressure increased from 594 million in 1975 to 1·13 billion in 2015, with the increase largely in low-income and middle-income countries. The global increase in the number of adults with raised blood pressure is a net effect of increase due to population growth and ageing, and decrease due to declining age-specific prevalence.

INTERPRETATION

During the past four decades, the highest worldwide blood pressure levels have shifted from high-income countries to low-income countries in south Asia and sub-Saharan Africa due to opposite trends, while blood pressure has been persistently high in central and eastern Europe.

FUNDING

Wellcome Trust.

Out-of-pocket costs and adherence to antihypertensive agents among older adults covered by the public drug insurance plan in Quebec

OBJECTIVE

To evaluate the effect of patient out-of-pocket costs on adherence to antihypertensive agents (AHA) in community-dwelling older adults covered by the public drug insurance plan in Quebec.

METHODS

This is a secondary analysis of data from the "Étude sur la santé des aînés" study (2005-2008) on community-dwelling older adults in Quebec aged 65 years and older (N=2,811). The final sample included 881 participants diagnosed with arterial hypertension and treated with AHA. Medication adherence was measured with the proportion of days covered over a 2-year follow-up period (<80% and ≥80%). Out-of-pocket costs for AHA, in Canadian dollars (CAD), at cohort entry were categorized as follows: $0, $0.01-$5.00, $5.01-$10.00, $10.01-$15.00 and $15.01-$36.00. Multivariable logistic regression models were constructed to study adherence to AHA as a function of out-of-pocket costs while controlling for several confounders. Models were also stratified by annual household income (<$15,000 CAD and ≥$15,000 CAD).

RESULTS

In this study, 80.8% of participants were adherent to their AHA. Among participants reporting an annual household income <$15,000 CAD, those with an out-of-pocket cost of $10.01-$15.00 CAD were significantly less adherent to their AHA than those with no contribution (OR =0.175, 95% CI: 0.042-0.740). Among participants reporting an income of ≥$15,000 CAD, those with out-of-pocket costs of $0.01-$5.00 CAD (OR =0.194; 95% CI: 0.048-0.787), $5.01-$10.00 CAD (OR =0.146; 95% CI: 0.036-0.589), $10.01-$15.00 CAD (OR =0.192; 95% CI: 0.047-0.777) and $15.01-$36.00 CAD (OR =0.160, 95% CI: 0.039-0.655) were significantly less adherent to their AHA than participants with no contribution.

CONCLUSION

Increased out-of-pocket costs are associated with non-adherence to AHA in older adults covered by a public drug insurance plan, more importantly in those reporting an annual household income ≥$15,000 CAD. A reduction in the amount of out-of-pocket costs and yearly maximum contribution for drugs may improve adherence to treatment.

Use of Pharmacy Sales Data to Assess Changes in Prescription- and Payment-Related Factors that Promote Adherence to Medications Commonly Used to Treat Hypertension, 2009 and 2014

BACKGROUND

Effective hypertension management often necessitates patients' adherence to the blood pressure (BP)-lowering medication regimen they are prescribed. Patients' adherence to that regimen can be affected by prescription- and payment-related factors that are typically controlled by prescribers, filling pharmacies, pharmacy benefit managers, and/or patients' health insurance plans. This study describes patterns and changes from 2009 to 2014 in factors that the literature reports are associated with increased adherence to BP-lowering medication.

METHODS AND FINDINGS

We use a robust source of United States prescription sales data-IMS Health's National Prescription Audit-to describe BP-lowering medication fill counts and spending in 2009 compared with 2014. Moreover, we describe patterns and changes in adherence-promoting factors across age groups, payment sources, and medication classes. From 2009 to 2014, the BP-lowering medication prescription fill count increased from 613.7 million to 653.0 million. Encouraging changes in adherence-promoting factors included: the share of generic fills increased from 82.5% to 95.0%; average days' supply per fill increased from 45.9 to 51.8 days; and average total (patient contribution) spending per years' supply decreased from $359 ($54) to $311 ($37). Possibly undesirable changes included: the percentage of fills for fixed-dose combinations decreased from 17.1% to 14.2% and acquired via mail order decreased from 10.7% to 8.2%. In 2014: 653.0 million fills occurred accounting for $28.81B in spending; adults aged 45-64 years had the highest percentage of fixed-dose combinations fills (16.9%); and fills with Medicaid as the payment source had the lowest average patient spending per fill ($1.19).

CONCLUSIONS

We identified both encouraging and possibly undesirable patterns and changes from 2009 to 2014 in factors that promote adherence to BP-lowering medications during this period. Continued tracking of these metrics using pharmacy sales data can help identify areas that can be addressed by clinical and policy interventions to improve adherence for medications commonly used to treat hypertension.

The Comparative Effectiveness of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers in Patients With Diabetes

The evidence examining the effect of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) on mortality in high-risk patients is conflicting. To further examine this controversy, the authors compared outcomes between ACE inhibitors and ARBs in a large clinical diabetes registry. A retrospective cohort of 87,472 incident users followed for 105,702 patient-years was analyzed. Average age was 53.1±10.1 years, 54.2% were men, and 14.4% had cardiovascular disease. All-cause hospitalization or all-cause mortality, the composite primary endpoint, occurred in 10,943 (12.5%) patients. Compared with ACE inhibitors, the adjusted hazard for ARBs was 0.90 (95% confidence interval, 0.87-0.94) for all-cause hospitalization or mortality; 0.95 (0.65-1.40) for mortality; 0.90 (0.87-0.94) for all-cause hospitalization; and 0.81 (0.74-0.89) for cardiovascular admission. ARB use was associated with a reduced, not increased, risk of hospitalization/mortality relative to ACE inhibition. This was driven by lower hospitalization, with a null mortality result.

Comparison of the Effect of Thiazide Diuretics and Other Antihypertensive Drugs on Central Blood Pressure: Cross-Sectional Analysis Among Nondiabetic Patients

Thiazide diuretics (TDs) are a cost-effective first-line therapy for uncomplicated hypertension; however, they are less prescribed than other options. The authors aimed to assess the noninferiority of TDs relative to different classes of antihypertensive medications in relation to central blood pressure. Cross-sectional data from the Quebec CARTaGENE project was used. Nondiabetic hypertensive participants on monotherapy for hypertension were studied. Separate adjusted models were constructed to establish noninferiority of TDs to non-TD antihypertensive medications for central blood pressure measurements. Models included a set of potential confounders. Of the 1194 hypertensive participants, 7.4% were taking TDs. We found that TDs were comparable with non-TD antihypertensive medications for central systolic blood pressure (adjusted regression coefficient, 0.45; 95% confidence interval, -1.61 to 2.50). No differences in other central measurements were noted. The results provide additional support that TDs are at least as effective as other first-line medications for treating uncomplicated hypertension.

Impact of ethnic-specific guidelines for anti-hypertensive prescribing in primary care in England: a longitudinal study

Background

In England, the National Institute for Health and Care Excellence (NICE) produces guidelines for the management of hypertension. In 2006, the NICE guidelines introduced an ethnic-age group algorithm based on the 2004 British Hypertension Society guidelines to guide antihypertensive drug prescription.

Methods

A longitudinal retrospective study with 15933 hypertensive patients aged 18 years or over and registered with 28 general practices in Wandsworth, London in 2007 was conducted to assess variations in antihypertensive prescribing. Logistic models were used to measure variations in the odds of being prescribed the 2006 NICE first line recommended monotherapy among NICE patient groups over the period.

Results

From 2000 to 2007, the percentage of patients prescribed the recommended monotherapy increased from 54.2% to 61.4% (p < 0.0001 for annual trend). Over the study period, black patients were more likely to be prescribed the recommended monotherapy than younger non-black patients (OR 0.16, 95% CI 0.12 – 0.21) and older non-black patients (OR 0.49, 95% CI 0.37 – 0.65). After the introduction of the NICE guidelines there was an increase in the NICE recommended monotherapy (OR 1.44, 95% CI 1.19 – 1.75) compared with the underlying trend. Compared to black patients, an increase in the use of recommended monotherapy was observed in younger non-black patients (OR 1.49, 95% CI 1.17 – 1.91) but not in older non-black patients (OR 0.58, 95% CI 0.46 – 0.74).

Conclusion

The introduction of the 2006 NICE guideline had the greatest impact on prescribing for younger non-black patients. Lower associated increases among black patients may be due to their higher levels of recommended prescribing at baseline. The analysis suggests that guidelines did not impact equally on all patient groups.

Prevalence, incidence, awareness and control of hypertension in the province of Quebec: perspective from administrative and survey data

OBJECTIVES

Hypertension is a major risk factor for cardiovascular diseases. Nearly one adult in four was diagnosed with hypertension in 2007-2008 in Canada. One of the objectives of this study was to determine whether the prevalence of hypertension in Quebec as assessed using administrative data is comparable to that specifically measured, especially for the elderly population.

METHODS

Trends in prevalence, incidence and mortality were examined using the Quebec Integrated Chronic Disease Surveillance System built from grouping numerous administrative databases from 1996-1997 to 2009-2010. Blood pressure measurements, hypertension prevalence, awareness and control were obtained in 1,706 Quebecers in the combined cycles of the Canadian Health Measures Survey.

RESULTS

Using administrative databases, 23.6% [95% confidence interval, 23.5-23.6] of the Quebec population (n=1,433,400) aged ≥20 years was diagnosed with hypertension in 2009-2010, an increase of 32.1% compared to 2000 2001. The incidence decreased by 27.3%. Among people aged ≥65 years, the prevalence rose to 69.0% [95% CI: 68.8 69.2] in women and 61.7% [95% CI: 61.5-61.9] in men. For people aged 20-79 years, the prevalence of hypertension was lower with the administrative data compared to the survey (20.2% and 23.1%, respectively). The level of awareness, treatment and control were 84.3%, 83.1% and 67.9%, respectively.

CONCLUSION

The prevalence of hypertension derived from administrative data is comparable to that obtained with a health measured survey. Elderly women (≥65 years) are a very high-risk subgroup. The levels of awareness, treatment and control of hypertension in Quebec are very high.

Impact of drug plans on adherence to and the cost of antihypertensive medications among patients covered by a universal drug insurance program

BACKGROUND

This study aimed to assess the impact of the type of drug plan on adherence to antihypertensive medication treatment as well as the cost of these medications within universal drug insurance programs.

METHODS

To compare adherence to antihypertensive medication treatment and the cost of antihypertensive medications between adults with public and private drug insurance in the province of Québec, Canada, we reconstructed a matched retrospective cohort by linking data recorded in 3 administrative databases between March 2008 and May 2010. The cohort included 186 privately and 1747 publicly insured patients aged 18-64 years who were treated with 1 or 2 antihypertensive medications. Adherence measured with the proportion of days covered (PDC) over 1 year and the cost of antihypertensive medications were evaluated for new and prevalent users separately.

RESULTS

More than 70% of patients were 50-64 years old and 90% of the publicly and 72% of the privately insured patients were using only 1 antihypertensive medication. The mean PDC among new users of 1 antihypertensive medication was 58.8% for privately insured patients and 65.0% for publicly insured patients, but the difference was not statistically significant. However, privately insured patients treated with 2 antihypertensive medications were more likely to be adherent (PDC-P, 15.0%; 95% confidence interval, 7.0-24.0). Privately insured patients (CAD$41.52) had to pay significantly more for their antihypertensive medications than did publicly insured patients (CAD$32.21).

CONCLUSIONS

The cost of antihypertensive medications was higher for patients with private drug insurance, although adherence was similar in both groups. The results may reflect regulation of dispensing fees for publicly insured patients.

Hospitalization for uncomplicated hypertension: an ambulatory care sensitive condition

BACKGROUND

Hospitalizations for ambulatory care sensitive conditions (ACSC) represent an indirect measure of access and quality of community care. This study explored hospitalization rates for 1 ACSC, uncomplicated hypertension, and the factors associated with hospitalization.

METHODS

A cohort of patients with incident hypertension, and their covariates, was defined using validated case definitions applied to International Classification of Disease administrative health data in 4 Canadian provinces between fiscal years 1997 and 2004. We applied the Canadian Institute for Health Information's case definition to detect all patients who had an ACSC hospitalization for uncomplicated hypertension. We employed logistic regression to assess factors associated with an ACSC hospitalization for uncomplicated hypertension.

RESULTS

The overall rate of hospitalizations for uncomplicated hypertension in the 4 provinces was 3.7 per 1000 hypertensive patients. The risk-adjusted rate was lowest among those in an urban setting (2.6 per 1000; 95% confidence interval [CI], 2.3-2.7), the highest income quintile (3.4 per 1000; 95% CI, 2.8-4.2), and those with no comorbidities (3.6 per 1000; 95% CI, 3.2-3.9). Overall, Newfoundland had the highest adjusted rate (5.7 per 1000; 95% CI, 4.9-6.7), and British Columbia had the lowest (3.7 per 1000; 95% CI, 3.4-4.2). The adjusted rate declined from 5.9 per 1000 in 1997 to 3.7 per 1000 in 2004.

CONCLUSIONS

We found that the rate of hospitalizations for uncomplicated hypertension has decreased over time, which might reflect improvements in community care. Geographic variations in the rate of hospitalizations indicate disparity among the provinces and those residing in rural regions.

Monitoring and evaluating efforts to control hypertension in Canada: why, how, and what it tells us needs to be done about current care gaps

Blood pressure surveillance, monitoring, and evaluation of programs to prevent and control hypertension are critical because increased blood pressure is a leading risk for premature death and disability. Since 2003, the Hypertension Outcomes Research Task Force has existed in Canada, with members who assist in the development and revision of surveys and conduct analyses that help guide hypertension programs. Although the Task Force has tracked a 5-fold increase in the control of hypertension (from 13% in 1985-1992 to 65% in 2007-2009), surveillance data also indicate that many "care gaps" remain. Fifty-four percent of people with diabetes and 34% of those without diabetes have blood pressure readings greater than their target. Treatment rates are high in those who are diagnosed (95%), but 17% of people with hypertension remain undiagnosed. Younger men (more so than women) are too often unaware of having hypertension. Although they are more likely to be aware of their diagnosis, older women are 2 times more likely to have uncontrolled hypertension than men; systolic blood pressure is high in over 80% of those with uncontrolled blood pressure (90% in women); and often people with hypertension are not provided comprehensive advice on healthy behaviours, or assisted in developing plans to control their blood pressure. Many current surveys do not have adequate statistical power to assess vulnerable populations; surveys of Aboriginal populations do not usually assess blood pressure, such that the burden of hypertension in these high risk populations cannot be assessed.

Spectrum of antihypertensive therapy in South Asians at a tertiary care hospital in Pakistan

Background

Despite available guidelines on hypertension (HTN), use of antihypertensives is variable. This study was designed to ascertain frequency of patients on monotherapy and > 1 antihypertensive therapy and also to ascertain proportion of patients on diuretic therapy.

Methods

It was a crossectional study conducted on 1191 adults(age > 18 yrs)hypertensive patients selected by computerized International Classification of Diseases -9-coordination and maintenance (ICD-9-CM) presenting to a tertiary care hospital in Pakistan. Data on demographics, comorbids, type of antihypertensive drug, number of antihypertensive drug and mean duration of antihypertensive drug was recorded over 1.5 year period (2008-09). Blood pressure was recorded on admission. Primary outcome was use of combination therapy and secondary outcome was use of diuretic therapy.

Results

A total of 1191 participants were included. Mean age(SD) was 62.55(12.47) years, 45.3%(540) were males. Diabetes was the most common comorbid; 46.3%(551). Approximately 85% of patients had controlled hypertension. On categorization of anti hypertensive use into 3 categories;41.2%(491) were on monotherapy,32.2%(384) were on 2 drug therapy,26.5%(316) were on ≥3 drug therapy. Among those who were on monotherapy for HTN;34%(167) were on calcium channel blockers,30.10%(148) were on beta blockers, 22.80%(112) were on Angiotensin converting enzyme (ACE) inhibitors,12%(59) were on diuretics and 2.20%(11) were on Angiotensin receptor blockers(ARB). Use of combination antihypertensive therapy was significantly high in patients with ischemic heart disease(IHD)(p < 0.001). Use of diuretics was in 31% (369) patients. Use of diuretics was significantly less in patients with comorbids of diabetes (p 0.02), Chronic kidney disease(CKD)(p 0.003), IHD (p 0.001) respectively

Conclusion

Most patients presenting to our tertiary care center were on combination therapy. Calcium channel blocker is the most common anti hypertensive drug used as monotherapy and betablockers are used as the most common antihypertensive in combination. Only a third of patients were on diuretic as an antihypertensive therapy.