Short-term adherence to β-blocker therapy among ethnic Chinese patients with hypertension: A cohort study

Association between the 8-item Morisky medication adherence scale (MMAS-8) score and glycaemic control among Chinese diabetes patients

Adherence with oral hypoglycaemic agent is crucial to achieve optimal glycaemic control. The 8-item Morisky Medication Adherence Scale (MMAS-8) has been frequently used, yet the association between MMAS-8 score and glycaemic control among Chinese diabetes patients is largely unknown. Two general out-patient clinics were randomly selected in a district with socio-demographic characteristics representative of the entire Hong Kong population. A consecutive sample of adult type-2 diabetes patients currently taking oral hypoglycaemic agents was included. The glycaemic control was reflected by the level of hemoglobin A1c (HbA1c) taken within the previous 6 months. Factors associated with poor glycaemic control (HbA1c ≥ 7.0%) were evaluated by linear regression analysis. From 565 eligible Chinese patients with an average age of 63.2 years (SD 9.7) and male proportion of 46.5%, the average HbA1c was 7.1% (SD 1.1%), and 52.0% had poor glycaemic control. The proportion of poor medication adherence (MMAS-8 ≤ 6) was 32.2%. After controlling for socio-demographics, lifestyle, medication use, and health characteristics, the MMAS-8 score was correlated with better glycaemic control (beta -0.095; 95%CI -0.164 to -0.026, P = .007). The MMAS-8 score had a weak and negative correlation with HbA1c level. The instrument should be applied with caution when predicting glycaemic control in clinical practice.

The incidence of cancer deaths among hypertensive patients in a large Chinese population: a cohort study

Current evidence is mixed regarding the association between antihypertensive prescriptions and cancer mortality. We evaluated this association in a large Chinese hypertensive population. We followed for five years all patients who were prescribed their first-ever antihypertensive agents between 2001 and 2005 in a public healthcare sector of Hong Kong. The association between antihypertensive drug class and cancer mortality was evaluated by Cox proportional hazard models with propensity score matching. Age, gender, socioeconomic status, service settings, district of residence, proportion of days covered reflecting medication adherence, and the number of comorbidities were adjusted. From 217,910 eligible patients, 9500 (4.4%) died from cancer within five years after their first-ever antihypertensive prescription. Most cancer deaths occurred in the digestive (38.9%) and respiratory system (30.4%); the breast (6.2%); and the lympho-hematopoietic tissues (5.3%). The proportion of patients who died from cancer was the highest in the calcium channel blocker (CCB) group (6.5%), followed by thiazide diuretics (4.4%), angiotensin converting enzyme inhibitors (4.2%) and β-blockers (2.6%). When compared with β-blockers, patients prescribed CCBs (Adjusted Hazard Ratio [AHR]=1.406, 95% C.I. 1.334-1.482, p<0.001) were more likely to die from cancer. Thiazide users were also more likely to suffer from cancer deaths (AHR=1.364, 95% C.I. 1.255-1.483, p<0.001), but became insignificant in stratified analysis. The association between cancer mortality and use of CCB, and perhaps thaizide, may alert physicians to the need for more meticulous and comprehensive care of these patients in clinical practice. We recommend prospective studies to evaluate cause-and-effect relationships of these associations.

Factors associated with multimorbidity and its link with poor blood pressure control among 223,286 hypertensive patients

Multimorbidity has become the norm worldwide as populations age. It remains, however, infrequently researched. This study evaluated factors associated with multimorbidity in a predominantly Chinese hypertensive population. We included all adult patients prescribed their first antihypertensive agents in the entire public sector in Hong Kong from a validated database. Multimorbidity was defined as having one or more medical conditions (cardiovascular diseases; respiratory diseases; diabetes or impaired fasting glucose; renal disease) in addition to hypertension. We studied the prevalence of multimorbidity and performed multinomial regression analyses to evaluate factors independently associated with multimorbidity. 223,286 hypertensive patients (average age of 59.9 years, SD 17.6) were included. The prevalence of having 0, 1 and ≥ 2 additional conditions was 59.6%, 32.8% and 7.5%, respectively. The most common conditions were cardiovascular disease (24.2%) and diabetes (23.0%), followed by respiratory disorders (14.6%) and renal disease (10.9%). Older age (>50 years), male sex, lower household income, receipt of social security allowance and suboptimal blood pressure control (>140 mmHg or >90 mmHg; >130 mmHg or >80 mmHg for diabetes patients; AOR = 3.38-4.49) were significantly associated with multimorbidity. There exists a synergistic effect among these variables as older (≥ 70 years), male patients receiving security allowance had substantially higher prevalence of multimorbidity (19.9% vs 7.5% among all patients). Multimorbidity is very common in hypertensive patients and its prevalence increased markedly with the presence of risk factors identified in this study. Hypertensive patients with multimorbidities should receive more meticulous clinical care as their blood pressure control tends to be poorer.

Exposure to air pollutants and mortality in hypertensive patients according to demography: a 10 year case-crossover study

This study evaluated whether short term exposures to NO2, O3, particulate matter <10 mm in diameter (PM10) were associated with higher risk of mortality. A total of 223,287 hypertensive patients attended public health-care services and newly prescribed at least 1 antihypertensive agent were followed-up for up to 5 years. A time-stratified, bi-directional case-crossover design was adopted. For all-cause mortality, significant positive associations were observed for NO2 and PM10 at lag 0-3 days per 10 μg/m(3) increase in concentration (excess risks 1.187%-2.501%). Significant positive associations were found for O3 at lag 1 and 2 days and the excess risks were 1.654% and 1.207%, respectively. We found similarly positive associations between these pollutants and respiratory disease mortality. These results were significant among those aged ≥65 years and in cold seasons only. Older hypertensive patients are susceptible to all-cause and respiratory disease-specific deaths from these air pollutants in cold weather.

Cardiovascular mortality in hypertensive patients newly prescribed perindopril vs. lisinopril: a 5-year cohort study of 15,622 Chinese subjects

BACKGROUND

Perindopril and lisinopril are two common ACE inhibitors prescribed for management of hypertension. Few studies have evaluated their comparative effectiveness to reduce mortality. This study compared the all-cause and cardiovascular related mortality among patients newly prescribed ACE inhibitors.

METHODS

All adult patients newly prescribed perindopril or lisinopril from 2001 to 2005 in all public clinics or hospitals in Hong Kong were retrospectively evaluated, and followed up until 2010. Patients prescribed the ACE inhibitors for less than a month were excluded. The all-cause mortality and cardiovascular-specific (i.e. coronary heart disease, heart failure and stroke) mortality were compared. Cox proportional hazard regression model was used to assess the mortality, controlling for age, sex, socioeconomic status, patient types, the presence of comorbidities, and medication adherence as measured by the proportion of days covered. An additional model using propensity scores was performed to minimize indication bias.

RESULTS

A total of 15,622 patients were included in this study, in which 6910 were perindopril users and 8712 lisinopril users. The all-cause mortality (22.2% vs. 20.0%, p<0.005) and cardiovascular mortality (6.5% vs. 5.6%, p<0.005) were higher among lisinopril users than perindopril users. From regression analyses, lisinopril users were 1.09-fold (95% C.I. 1.01-1.16) and 1.18-fold (95% C.I. 1.02-1.35) more likely to die from any-cause and cardiovascular diseases, respectively. Age-stratified analysis showed that this significant difference was observed only among patients aged >70 years. The additional models controlled for propensity scores yielded comparable results.

CONCLUSIONS

The long-term all-cause and cardiovascular related mortality rates of lisinopril users was significantly different from those of perindopril users. These findings showed that intra-class variation on mortality exists among ACE inhibitors among those aged 70 years or older. Future studies should consider a longer, large-scale randomized controlled trial to compare the effectiveness between different medications in the ACEI class, especially among the elderly.

Socioeconomic status and nonadherence to antihypertensive drugs: a systematic review and meta-analysis

BACKGROUND

Although conventional wisdom suggests that low socioeconomic status (SES) is a robust predictor of medication nonadherence, the strength of this association remains unclear.

OBJECTIVES

1) To estimate the proportion of studies that identified SES as a potential risk indicator of nonadherence, 2) to describe the type of SES measurements, and 3) to quantify the association between SES and nonadherence to antihypertensive pharmacotherapy.

METHODS

A systematic review and meta-analysis research design was used. We searched multiple electronic databases for studies in English or French examining nonadherence to antihypertensive medications measured by electronic prescription databases where explanatory factors were considered. Two authors independently assessed quality, described the SES measure(s), and recorded its association with nonadherence to antihypertensives. A random-effects model meta-analysis was performed, and heterogeneity was examined by using the I(2) statistic.

RESULTS

Fifty-six studies with 4,780,293 subjects met the inclusion criteria. Twenty-four of these studies (43%) did not report any SES measures. When it was reported (n = 32), only seven (13%) examined more than one component but none performed a multidimensional assessment. Most of the studies relied on income or income-related measures (such as prescription-drug benefits or co-payments) (27 of 32 [84%]). Meta-analysis could be quantified in 40 cohorts reported in 30 studies. Overall, the pooled adjusted risk estimate for nonadherence according to SES (high vs. low) was 0.89 (95% confidence interval 0.87-0.92; I(2) = 95%; P < 0.001). Similar patterns were observed in all subgroups examined.

CONCLUSIONS

Published studies have not found a strong association between low SES and nonadherence to antihypertensive medications. However, important limitations in the assessment of SES can be identified in virtually all studies. Future studies are required to ascertain whether a stronger association is observed when SES is determined by comprehensive measures.

The healthcare burden of hypertension in Asia

As the leading global risk for mortality, hypertension (HT) is a common healthcare problem in the world. The total number of patients with HT is likely to grow in the next few decades as the population age and the prevalence of obesity and diabetes increase. HT, as a major modifiable risk factor for cardiovascular disease, results in more deaths than any other risk factors, including diabetes and cigarette smoking. High prevalence, inadequate awareness, suboptimal treatment and low rate of achieving guideline-recommended target blood pressure control are key factors leading to severe cardiovascular complications that impose a heavy socioeconomic burden, especially in developing countries. Asia is the world's largest and most populous continent with approximately 4.3 billion people, hosting 60% of the world's current human population, and has a high growth rate. Asia differs very widely from the West with regard to ethnic groups, cultures, environments, economics, historical ties and government systems. Therefore, the purpose of this review is to comprehensively summarise the epidemiology, treatment practice and the status of control of HT in different Asian countries in order to guide the future prevention and management in this part of the world.

Predictors of the incidence of all-cause mortality and deaths due to diabetes and renal diseases among patients newly prescribed antihypertensive agents: a cohort study

BACKGROUND

Randomized trials have shown that the major antihypertensive drug classes are similarly effective to reduce mortality, but whether these drug class difference exists in clinical practice has been scarcely explored. This study evaluated the association between antihypertensive drug class, all-cause mortality and deaths due to diabetes or renal disease in real-life clinical settings.

METHODS

A clinical database in Hong Kong included all patients who were prescribed their first-ever antihypertensive agents between 2001 and 2005 from the public healthcare sector. All patients were followed up for five years, and grouped according to the initial antihypertensive prescription. The associations between antihypertensive drug class, all-cause mortality or combined diabetes and renal mortality, respectively, were evaluated by Cox proportional hazard models.

RESULTS

From 218,047 eligible patients, 33,288 (15.3%) died within five years after their first-ever antihypertensive prescription and among which 1055 patients (0.48%) died of diabetes or renal disease. After adjusted for age, gender, socioeconomic status, service settings, district of residence, medication adherence, and the number of comorbidities, each drug class was similarly likely to be associated with mortality due to diabetes or renal disease [Adjusted Hazard Ratios (AHR) ranged from 0.92 to 1.73, p=0.287-0.939] and all-cause mortality (AHR ranged from 0.83 to 1.02) except for beta-blockers (AHR=0.815, 95% C.I. 0.68-0.87, p=0.024) when ACEI was used as a reference group in propensity score-adjusted analysis.

CONCLUSIONS

These findings provide real-life evidence reinforcing that any major antihypertensive drug class is suitable as a first-line agent for management of hypertension as recommended by international guidelines.

Medication adherence to first-line antihypertensive drug class in a large Chinese population

PURPOSE

Suboptimal adherence to antihypertensive agents leads to adverse clinical outcomes. This study aims to evaluate the association between first-line antihypertensive drug class and medication adherence in a large Chinese population.

METHODS

All patients prescribed ≥ one antihypertensive drug in 2001-2003 and 2005 who have paid at least two consecutive clinic visits in the public healthcare system of Hong Kong were included. We excluded patients who have followed-up in the clinics for ≤ 30 days. Interval-based Proportion of Days Covered (PDC) was used to assess medication adherence. All patients were followed-up for up to 5 years. Binary logistic regression analysis was used to evaluate the factors associated with optimal adherence, defined as PDC ≥ 80%.

RESULTS

From 147,914 eligible patients, 69.2% were adherent to the antihypertensive prescriptions. When compared with angiotensin converting enzyme inhibitors (ACEIs), patients initially prescribed α-blockers (adjusted odds ratio [AOR]=0.234, 95% C.I. 0.215-0.256), β-blockers (AOR=0.447, 95% C.I. 0.420, 0.477), thiazide diuretics (AOR=0.431 95% C.I. 0.399, 0.466) and calcium channel blockers (AOR=0.451, 95% C.I. 0.423, 0.481) were significantly less likely to be drug adherers. Angiotensin receptor blockers (ARBs) and fixed-dose combination therapies were similarly likely to be medication adherent. Older age, male gender, visits in general out-patient clinics, residence in urbanized regions, and the presence of comorbidity were positively associated with optimal drug adherence.

CONCLUSION

Patients receiving initial prescriptions of ACEIs, ARB and combination therapy had more favorable adherence profiles than the other major antihypertensive classes in real-life clinical practice.

Determinants of medication adherence to antihypertensive medications among a Chinese population using Morisky Medication Adherence Scale

BACKGROUND AND OBJECTIVES

Poor adherence to medications is one of the major public health challenges. Only one-third of the population reported successful control of blood pressure, mostly caused by poor drug adherence. However, there are relatively few reports studying the adherence levels and their associated factors among Chinese patients. This study aimed to study the adherence profiles and the factors associated with antihypertensive drug adherence among Chinese patients.

METHODS

A cross-sectional study was conducted in an outpatient clinic located in the New Territories Region of Hong Kong. Adult patients who were currently taking at least one antihypertensive drug were invited to complete a self-administered questionnaire, consisting of basic socio-demographic profile, self-perceived health status, and self-reported medication adherence. The outcome measure was the Morisky Medication Adherence Scale (MMAS-8). Good adherence was defined as MMAS scores greater than 6 points (out of a total score of 8 points).

RESULTS

From 1114 patients, 725 (65.1%) had good adherence to antihypertensive agents. Binary logistic regression analysis was conducted. Younger age, shorter duration of antihypertensive agents used, job status being employed, and poor or very poor self-perceived health status were negatively associated with drug adherence.

CONCLUSION

This study reported a high proportion of poor medication adherence among hypertensive subjects. Patients with factors associated with poor adherence should be more closely monitored to optimize their drug taking behavior.

Drug adherence and the incidence of coronary heart disease- and stroke-specific mortality among 218,047 patients newly prescribed an antihypertensive medication: a five-year cohort study

Background

Randomized trials have shown that optimal adherence to antihypertensive agents could protect against cardiovascular diseases, but whether adherence reduces cardiovascular deaths in community settings has not been explored so fully. This study evaluates the association between antihypertensive adherence and cardiovascular (coronary heart disease and stroke) mortality in the primary care settings.

Methods

From a territory-wide database in Hong Kong, we included all patients who were prescribed their first-ever antihypertensive agents in the years between 2001 and 2005 from the public healthcare sector. All patients were followed up for five years, and assigned as having poor (Proportion of Days Covered [PDC] < 40%), intermediate (40–79%), and high (≥ 80%) adherence to antihypertensive agents. The association between antihypertensive adherence and cardiovascular mortality was evaluated by using the Cox proportional hazard models.

Results

From a total of 218,047 eligible patients, 3825 patients (1.75%) died of cardiovascular disease within five years after having received their first-ever antihypertensive agents. The proportions of patients having poor, intermediate, and high medication adherence were 32.9%, 12.1%, and 55.0%, respectively. Higher adherence levels at PDC 40%–79% (HR = 0.46, 95% C.I. 0.41–0.52, p < 0.001) and ≥ 80% (HR = 0.91, 95% C.I. 0.85–0.98, p = 0.012) were significantly less likely to be associated with mortality than the poor adherence (PDC0.040) group.

Conclusions

Better antihypertensive adherence was associated with lower cardiovascular mortality. This highlights the need to promote adherence through strategies which have been proved to be effective in clinical settings.

β-blocker withdrawal among patients presenting for surgery from home

OBJECTIVE

This study sought to measure the prevalence of perioperative β-blocker noncompliance by patients who were prescribed long-term β-blocker therapy and presented for surgery from home. The effect of patient noncompliance on the presenting heart rate on the day of surgery also was examined.

DESIGN

Prospective observational study with outcome data obtained from reviews of medical records.

SETTING

The preoperative clinic and operating rooms of a Veterans Administration hospital.

PARTICIPANTS

Patients on long-term β-blocker therapy who presented from home for surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic and comorbidity data and data on self-reported compliance to β-blocker therapy, vital signs on the initial day of surgery, and recent ambulatory vital signs were collected. Ten of 50 subjects (20%; 95% confidence interval, 9-31) reported not taking their β-blocker on the day of surgery. These self-reported nonadherers exhibited a higher presenting heart rate on the day of surgery than adherent subjects (median, 78 v 65 beats/min; p = 0.02 by Wilcoxon rank-sum test). The difference-in-difference analysis in heart rate between baseline primary care and the day of surgery also was statistically significant between compliant and noncompliant subjects (-7 v + 12.5 beats/min; p < 0.00001).

CONCLUSIONS

Patient self-report and physiologic data documented a failure to take β-blockers and possible β-blocker withdrawal in 20% of patients who presented for surgery from home. If these findings are confirmed in larger studies, improved patient understanding of and compliance with medication instructions during preoperative visits should be a focus of future quality improvement initiatives.

Subjects at risk of discontinuation of lipid-lowering agents: a 6-month cohort study among 12,875 patients in a chinese population

BACKGROUND

Dyslipidemia is a significant health problem, and persistent use of lipid-lowering agents among dyslipidemic patients is clinically important. However, few studies have evaluated the profiles of medication discontinuation among ethnic Chinese patients.

OBJECTIVE

The objective of this study was to evaluate the level of medication adherence among Chinese patients who were prescribed a lipid-lowering drug and to investigate factors that could help physicians identify patients at risk for discontinuing their medication.

METHODS

All patients who attended any primary care clinic in 1 territory of Hong Kong and were prescribed at least 1 lipid-lowering agent from January 2004 to June 2007 were included. The incidences of drug discontinuation within 180 days after drug prescriptions were measured, and the factors associated with discontinuation using binary logistic regression analyzes were evaluated.

RESULTS

Of the 12,875 eligible patients, the majority were prescribed fibrates (54.4%) and statins (45.1%). Among the patients, 17.0% discontinued their medication. Older patients (adjusted odds ratio [aOR] = 0.72-0.79 for patients >50 years), male subjects (aOR = 0.87; 95% CI, 0.78-0.97; P = 0.009), fee payers (aOR = 0.88; 95% CI, 0.78-0.99; P = 0.029), attendees in family medicine specialist clinics (aOR = 0.82; 95% CI, 0.70-0.96; P = 0.013), residents in rural districts (aOR = 0.52; 95% CI, 0.44-0.60; P < 0.001), follow-up visitors (aOR = 0.60; 95% CI, 0.54-0.66; P < 0.001), patients with comorbidities (aOR = 0.39; 95% CI, 0.35-0.44; P < 0.001 for 1 comorbidity and aOR = 0.28; 95% CI, 0.25-0.33; P < 0.001 for at least 2 comorbidities), and persons who use fibrates (aOR = 0.56; 95% CI, 0.49-0.64; P < 0.001) were significantly less likely to discontinue their medication.

CONCLUSIONS

The findings of these associated factors were new for ethnic Chinese patients. These findings could help physicians identify patients who had been prescribed a lipid-lowering agent who were at higher risk of discontinuing their medication. Their medication-taking behavior should be monitored more closely, and future studies should evaluate the reasons of drug discontinuation.

Adherence to lipid-lowering agents among 11,042 patients in clinical practice

AIMS

Dyslipidaemia is a poorly-controlled condition in clinical practice largely because of poor adherence to medication regimens by patients. This study evaluated the levels of and factors associated with adherence to lipid-lowering agents in a large Chinese population.

METHODS

From a validated clinical database, we included all patients who attended any public, primary care clinics in one large Territory of Hong Kong for medication refill at least twice during the study period January 2004 to June 2007. The major outcome variable was Medication Possession Ratio (MPR), an internationally-recognised metric to measure drug adherence. The factors associated with optimal drug adherence (MPR ≥ 0.8) were evaluated by multivariate regression analysis.

RESULTS

From 11,042 eligible patients, 90% were adherent. After adjusting for patients' age, gender, socioeconomic status, service type, district of residence, visit type (new visits vs. follow-up visits), the number of comorbidities and the drug class (statin vs. fibrates), older patients [aged 50-59 years; adjusted odds ratio (AOR) 1.30, p = 0.009; 60-69 years; AOR 1.53, p < 0.001; ≥ 70 years; AOR 1.72, p < 0.001], attendance in family medicine specialist clinics (FMSC; AOR 1.56, p < 0.001), follow-up visits (AOR 2.93, p < 0.001) and the presence of comorbidities (one comorbidity; AOR 1.45, p < 0.001; ≥ 2 comorbidities; AOR 1.56, p < 0.001) were associated with optimal drug adherence.

DISCUSSION AND CONCLUSION

These findings carry an implication that younger subjects, new patients, visitors in clinics other than FMSC and those without comorbidities should receive more meticulous monitoring of their medication-taking behaviour. Future studies should evaluate the major reasons for non-adherence among them.