Nonadherence to antihypertensive medications and associated factors in general medicine clinics

Factors related to medication adherence in patients with hypertension in Iran: a systematic review study

OBJECTIVES

This study aimed to review the available studies of the factors in Iranian hypertensive patients' adherence to drug treatment.

METHODS

Four Persian databases and seven English databases were searched. The articles, which were published from 2000 to 2022 in Persian and English and examined the adherence to drug treatment in the Iranian population of adults with high blood pressure, were reviewed. Based on the primary examination, 31 of the initial 1062 articles met the inclusion criteria and were included in the analysis. The evidence, which was provided by the examined articles, was summarized and discussed using the 5-dimensional framework of adherence to long-term treatments, which was developed by WHO.

RESULTS

The factors that significantly correlated with adherence to drug treatment in the examined studies were: (1) factors that were related to the health team or the health system: patients' satisfaction with their doctor-patient relationship; (2) factors that were related to the conditions: the number of concomitant diseases, high quality of life and the implementation of effective interventions; (3) factors which were related to the treatment: long duration of illness, short intervals between the visits, duration of treatment, lower numbers of drugs, and the patient's blood pressure control; and (4) factors that were related to the patient: self-efficacy, health literacy, social support, locus of control, illness perception, beliefs, attitude, knowledge, and cues to action.

CONCLUSION

It is possible to draw definite conclusions about the factors which affect adherence to drug treatment in patients with high blood pressure because most of the relevant studies have been cross-sectional. Therefore, in the future, valuable results can be obtained by conducting more studies that preferably use objective instruments for assessing adherence to drug treatment.

Medication Adherence and Blood Pressure Control Among Hypertensive Outpatients Attending a Tertiary Cardiovascular Hospital in Tanzania: A Cross-Sectional Study

Background

Notwithstanding the availability of effective treatments, asymptomatic nature and the interminable treatment length, adherence to medication remains a substantial challenge among patients with hypertension. Suboptimal adherence to BP-lowering agents is a growing global concern that is associated with the substantial worsening of disease, increased service utilization and health-care cost escalation. This study aimed to explore medication adherence and its associated factors among hypertension outpatients attending a tertiary-level cardiovascular hospital in Tanzania.

Methods

The pill count adherence ratio (PCAR) was used to compute adherence rate. In descriptive analyses, adherence was dichotomized and consumption of less than 80% of the prescribed medications was used to denote poor adherence. Logistic regression analyses was used to determine factors associated with adherence.

Results

A total of 849 outpatients taking antihypertensive drugs for ≥1 month prior to recruitment were randomly enrolled in this study. The mean age was 59.9 years and about two-thirds were females. Overall, a total of 653 (76.9%) participants had good adherence and 367 (43.2%) had their blood pressure controlled. Multivariate logistic regression analysis showed; lack of a health insurance (OR 0.5, 95% CI 0.3-0.7, p<0.01), last BP measurement >1 week (OR 0.6, 95% CI 0.4-0.8, p<0.01), last clinic attendance >1 month (OR 0.4, 95% CI 0.3-0.6, p<0.001), frequent unavailability of drugs (OR 0.6, 95% CI 0.3-0.9, p = 0.03), running out of medication before the next appointment (OR 0.6, 95% CI 0.4-0.9, p = 0.01) and stopping medications when asymptomatic (OR 0.6, 95% CI 0.4-0.8, p<0.001) to be independent associated factors for poor adherence.

Conclusion

A substantial proportion of hypertensive outpatients in this tertiary-level setting had good medication adherence. Nonetheless, observed suboptimal blood pressure control regardless of a fairly satisfactory adherence rate suggests that lifestyle modification plays a central role in hypertension management.

Non-adherence to antihypertensive pharmacotherapy in Buea, Cameroon: a cross-sectional community-based study

Background

Hypertension is a challenging public health problem with a huge burden in the developing countries. Non-adherence to antihypertensive treatment is a big obstacle in blood pressure (BP) control and favours disease progression to complications. Our objectives were to determine the rate of non-adherence to antihypertensive pharmacotherapy, investigate factors associated with non-adherence, and to assess the association between non-adherence and BP control in the Buea Health District (BHD), Cameroon.

Methods

A community-based cross-sectional study using stratified cluster sampling was conducted in the BHD from November 2013 – March 2014. Eligible consenting adult participants had their BP measured and classified using the Joint National Committee VII criteria. The Morisky medication adherence scale was used to assess adherence to BP lowering medication. Multivariable logistic regression models were used to predict non-adherence.

Results

One hundred and eighty-three participants were recruited with mean age of 55.9 years. Overall, 67.7% (95% CI: 59.8–73.6%) of participants were non-adherent to their medications. After adjusting for age, sex and other covariates, forgetfulness (aOR = 7.9, 95%CI: 3.0–20.8), multiple daily doses (aOR = 2.5, 95%CI: 1.2–5.6), financial constraints (aOR = 2.8, 95%CI: 1.1–6.9) and adverse drug effects (aOR = 7.6, 95%CI: 1.7–33.0) independently predicted non-adherence to anti-hypertensive medication. BP was controlled in only 21.3% of participants and was better in those who were adherent to medication (47.5% versus 8.2%, p <  0.01).

Conclusion

At least two of every three hypertensive patients in the Buea Health District are non-adherent to treatment. Forgetfulness, multiple daily doses of medication, financial constraints and medication adverse effects are the major predictors of non-adherence in hypertensive patients. These factors should be targeted to improve adherence and BP control, which will contribute to stem hypertension-related morbidity and mortality.

Assessment of blood pressure control in adult hypertensive patients in eastern Sudan

Background

The rate of blood pressure (BP) control in adult hypertensive patients is poor and the reasons for poor control of BP pressure are not fully understood globally. This study aimed to assess the rate and factors associated with BP control in adult hypertensive patients in Sudan.

Methods

A hospital-based cross-sectional study was conducted in adult hypertensive Sudanese patients at Gadarif Hospital in eastern Sudan from November 2016 to March 2017. Information on sociodemographic characteristics of the participants, comorbidities, antihypertensive medication, and adherence to antihypertensive medication was gathered from patients using a questionnaire. Fasting cholesterol and triglyceride levels were measured.

Results

A total of 380 patients were enrolled. Of them, 234 (61.6%) were women. The mean (SD) age of the participants was 57.8 (11.1) years (range: 25–93 years). Over one-third (n = 147, 38.7%) of the participants were taking more than one antihypertensive medication. Approximately one-third (29.5%) of the participants were non-adherent to medication. The rate of BP control was 45.3%. In binary logistic regression analyses, age, sex, physical inactivity, adding salt to food, drinking coffee, body mass index, and the lipid profile were not associated with uncontrolled BP. However, non-adherence to medication was the main factor associated with uncontrolled BP (odds ratio = 5.29, 95% confidence interval = 3.16–8.83, P <  0.001).

Conclusions

Almost half of hypertensive patients in follow-up have uncontrolled BP, mainly due to non-adherence to medicine. We recommend further research on drug adherence to improve the rate of BP control in this setting (Gadarif) of the Sudan.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0769-5) contains supplementary material, which is available to authorized users.

Previously undiagnosed risk factors and medication nonadherence are prevalent in young adults with first-ever stroke

PURPOSE

The incidence of stroke and prevalence of traditional vascular risk factors (VRFs) in young adults (age < 55 y) are both increasing. Young patients tend to be unaware of their VRFs and to have lower medication adherence. We examined how age affects the prevalence of previously undiagnosed VRFs and the extent of medication nonadherence among stroke patients.

METHODS

Using Taiwan's National Health Insurance Research Database, we identified consecutive adult patients with first-ever stroke between 2000 and 2013. Diagnosis of hypertension, diabetes, and hyperlipidemia was ascertained using validated methods. We investigated (1) the proportion of patients who had undiagnosed VRFs within 3 years before stroke and (2) the proportion of nonadherence to medications among patients who had a previously diagnosed VRF.

RESULTS

Among stroke patients with hypertension (n = 9722), diabetes (n = 4751), and hyperlipidemia (n = 4486), 24.9%, 20.8%, and 55.0%, respectively, had not been diagnosed before stroke, whereas 56.0%, 66.7%, and 32.5%, respectively, had been diagnosed at least 1 year before stroke. The proportions of medication nonadherence were 71.5%, 64.3%, and 88.4% in patients with previously diagnosed hypertension, diabetes, and hyperlipidemia, respectively. In multivariate analysis, younger age was independently associated with undiagnosed hypertension before stroke as well as medication nonadherence in patients with previously diagnosed hypertension or diabetes.

CONCLUSIONS

Previously undiagnosed hypertension and nonadherence to treatment of hypertension and diabetes were more prevalent in young adult patients with first-ever stroke in Taiwan. Interventions targeting young people to promote early detection and adequate control of VRFs should be encouraged.

Relationship between patients' knowledge and medication adherence among patients with hypertension

OBJECTIVE

The purpose of this study was to investigate the relationship between knowledge on arterial hypertension (AH) and its management, and adherence to pharmaceutical treatment.

METHODS

The study included 233 patients diagnosed with AH and treated with hypotensive drugs for at least 1 year. The 8-item © Morisky Medication Adherence Scale (MMAS-8) and the Hypertension Knowledge-Level Scale (HK-LS) were used.

RESULTS

Sixty-three percent of the patients had a low level of knowledge on AH, with the smallest proportion of correct answers provided for items related to non-pharmaceutical treatment, diet, hypertension definition, and drug adherence. When compared to patients with a high level of knowledge, those with a low knowledge had lower scores in the MMAS (6.45±1.45 vs 7.08±1.04; P=0.038). Multiple-factor analysis showed that statistically significant independent determinants of good adherence included a high level of knowledge (β=0.208; P=0.001), non-pharmaceutical treatment (β=0.182; P=0.006), and frequent blood pressure measurements (β=0.183; P=0.004). The most significant factor in MMAS was knowledge in the "drug adherence" domain (ρ=0.303; P<0.001).

CONCLUSION

Patients' knowledge on hypertension is a significant independent determinant of good adherence. Other independent determinants include non-pharmaceutical treatment and regular blood pressure measurements.

IMPLICATION FOR PRACTICE

The identification of knowledge deficits as a factor contributing to lack of adherence and poor hypertension control remains a key challenge for multidisciplinary team caring for patients with hypertension.