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 Table of Contents  
Year : 2021  |  Volume : 65  |  Issue : 2  |  Page : 198-202  

Adherence to anti-hypertensive medications and its determinants: A study among hypertensive stroke patients in a tertiary care government hospital of West Bengal

1 3rd Professional MBBS Part-2 Student, R G Kar Medical College and Hospital, Kolkata, West Bengal, India
2 Associate Professor, Department of Community Medicine, R.G. Kar Medical College and Hospital, Kolkata, West Bengal, India
3 Professor, Department of General Medicine, R.G. Kar Medical College and Hospital, Kolkata, West Bengal, India
4 Professor, Department of Neuromedicine, Bangur Institute of Neurosciences and IPGME and R, Kolkata, West Bengal, India
5 Professor and Head, Department of Psychiatry, KPC Medical College and Hospital, Kolkata, West Bengal, India
6 Assistant Professor, Department of Neuromedicine, Bangur Institute of Neurosciences and IPGME and R, Kolkata, West Bengal, India

Date of Submission15-Oct-2020
Date of Decision19-Jan-2021
Date of Acceptance23-Mar-2021
Date of Web Publication14-Jun-2021

Correspondence Address:
Adrija Ray
7, Umakanta Sen Lane, Shantiban Housing Complex, Kolkata - 700 030, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijph.IJPH_1254_20

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There is a paucity of antihypertensive drug adherence studies among stroke patients in West Bengal. With an aim to identify antihypertensive drug adherence and its determinants, this descriptive cross-sectional study was conducted for 2 months among a calculated sample of 133 study participants using predesigned and pretested schedule, the metric “Proportion of days covered (PDC),” and the Morisky, Green, and Levine (MGL) Scale. Data were compiled and analyzed using SPSS software (version 20.0). Adherence rates were 31.6% and 44.4% based on the MGL scale and PDC method, respectively. Higher adherence was significantly associated with increased age (P = 0.006), higher literacy (P = 0.013), increased interval between diagnosis of hypertension and present symptom (P = 0.001), a greater gap between antihypertensive treatment initiation and present symptom (P = 0.003), receiving advice on regular drug intake (P = 0.000), and registered medical practitioner prescribing the medication (P = 0.007).

Keywords: Adherence, antihypertensives, determinants, stroke

How to cite this article:
Ray A, Ray TG, Pal J, Ray BK, Sanyal D, Dubey S. Adherence to anti-hypertensive medications and its determinants: A study among hypertensive stroke patients in a tertiary care government hospital of West Bengal. Indian J Public Health 2021;65:198-202

How to cite this URL:
Ray A, Ray TG, Pal J, Ray BK, Sanyal D, Dubey S. Adherence to anti-hypertensive medications and its determinants: A study among hypertensive stroke patients in a tertiary care government hospital of West Bengal. Indian J Public Health [serial online] 2021 [cited 2023 Mar 26];65:198-202. Available from:

Suboptimal or nonadherence to prescribed antihypertensives contributes to the burden of uncontrolled hypertension resulting in an increased incidence of stroke. In India, the reported proportion of stroke patients with hypertension is 82.8%–85%.[1] Drug adherence studies from eastern India including West Bengal are scarce. This study aimed to assess adherence to antihypertensive medications and its determinants among the study subjects.

This observational, descriptive, cross-sectional study was conducted for 2 months in the general medicine indoor of a tertiary care hospital in West Bengal. All admitted stroke cases, aged ≥18 years, with known preexisting hypertension who were already prescribed antihypertensive medications at least a month prior to the present symptom were the study subjects. Patients unable to communicate or without close family members to provide history in spite of five bedside visits and those receiving indigenous medicines were excluded from the study.

A sample size of 133 was obtained considering the proportion of stroke cases under treatment for preexisting hypertension with overall good adherence to antihypertensive (P) as 67.2% based on a previous study,[2] an absolute precision of 8, and standard normal deviate as 1.96 with 95% confidence level. Convenience sampling technique was adopted to select consenting study subjects meeting inclusion and exclusion criteria. Patients or close family members were interviewed using a predesigned, pretested schedule with the variable proportion of days covered (PDC) incorporated[3] in it and Morisky, Green, and Levine (MGL) Scale.[4]

Operational definitions and descriptions followed in the study were as follows:

  1. Stroke: “Rapidly developing clinical signs of focal (or global) disturbance of cerebral function, with symptoms lasting 24 h or longer or leading to death, with no apparent cause other than of vascular origin"(WHO)[5]
  2. Hypertension: Systolic blood pressure greater than 140 mm Hg and/or diastolic blood pressure greater than 90 mm Hg or receipt of antihypertensive medication (JNC-VII criteria)[5]
  3. Medication adherence was measured using:

  4. MGL scale: The patients were considered adherent if they scored more than 3 on the scale.[4]


    The number of days “covered” signifies the number of days covered by antihypertensive medications. For measurement of denominator, a recall period of 4 months preceding data collection was considered (inclusion criteria included prescription of antihypertensive medications at least a month prior to the onset of present symptom). In assessment of days covered, for a patient receiving more than one drug , a day was only considered “covered” when all medications were taken by the patient. Patients with PDC≥80% was considered adherent.

  5. First-ever stroke: Clinical stroke occurring in patients with no previous stroke event[5]
  6. Recurrent stroke: New stroke events occurring after 28 days of the index event[5]
  7. Pattern of taking antihypertensive drugs: Regular – when percentage of days covered is 100% and was considered irregular when percentage of days covered is <100%.

Collected data were compiled and analyzed using IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. The frequencies, percentages of various categorical variables, mean, and standard deviation of various continuous variables were used as summary measures of the data. Kappa statistic was used to assess mutual agreement between the two methods of medication adherence. A Chi-square test or Fisher's exact test was used to compare proportions. In case of inconclusive Fisher's exact test, Monte Carlo approximation was done. In all cases, two-tailed tests were used, and P ≤ 0.05 was considered statistically significant. Binary logistic regression was applied to identify the predictors for medication adherence from among those predictors that were found to be significant in univariate analysis.

The study had approval of Institutional Ethics Committee (Reference number: RKC/600 dated May 10, 2019).

[Table 1] summarizes sociodemographic characteristics and medical history of study subjects. Age of study subjects ranged from 35 to 90 years (mean – 63.27 ± 11.99 years, 51.1% aged >60 years). The average monthly family income of patients was Rs. 8289.09 ± 7972.46. Monthly expenditure on antihypertensives was < Rs. 100 in 40 (30.1%), Rs. 100–199 in 56 (42.1%), Rs. 200–300 in 10 (7.5%), and > Rs. 300 in 27 (20.3%) cases.
Table 1: Relationship between status of adherence to antihypertensives and sociodemographic and medical history related characteristics of study subjects (n=133)

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Antihypertensive adherence rates were 42 (31.6%) and 59 (44.4%) based on the MGL scale and PDC method, respectively. Agreement between the two medication adherence methods was assessed by kappa statistic. Slight agreement (kappa value = 0.204, P = 0.000) was observed between the two methods.

On univariate analysis, adherence to antihypertensive medications was significantly associated with age (P = 0.007, odds ratio [OR] = 0.377, 95% confidence interval [CI] = 0.186–0.764), literacy status (P = 0.014, OR = 0.374, 95% CI = 0.171–0.822), interval between diagnosis of hypertension and onset of present symptom (P = 0.011, OR = 0.323, 95% CI = 0.135–0.773), gap between initiation of antihypertensive treatment and onset of present symptom (P = 0.012, OR = 0.328, 95% CI = 0.138–0.779), monthly expenditure on antihypertensives (P = 0.015, OR = 0.270, 95% CI = 0.094-0.777), receiving advice on importance of regular intake of drugs (P = 0.000, OR = 0.060, 95% CI = 0.017–0.208), and type of medical practitioner prescribing antihypertensive medication (P = 0.012, OR = 0.191, 95% CI = 0.053–0.691). Younger age, illiteracy, less gap between onset of present symptom and diagnosis of hypertension or initiation of antihypertensive treatment, less monthly expenditure on antihypertensives, not receiving advice regarding regular drug intake, and prescribing health-care provider being other than registered medical practitioners are more likely to be associated with nonadherence. Independent variables found significant on univariate analysis were put into a multivariable regression model (vide [Table 2]). Finally, age and status of receiving advice regarding the importance of regular intake of drug retained their significance with an explained variance of 43.7% (Nagelkerke pseudo R square) for adherence to antihypertensive medication. The significance of the model for logistic regression was tested by Omnibus Tests of Model Coefficients and the model was found to be significant (P = 0.000). Fitness of the model was tested by Hosmer and Lemeshow test and the model did fit the data (P = 0.939).
Table 2: Multivariable logistic regression analysis between adherence to antihypertensive medication and its predictors

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The lower adherence rate (44.4%) in our study as compared to other studies (53%–91% in Western population,[6] 77.0% in Pakistan,[2] and 67.2% in Northwest Ethiopia[2]) probably originates from differences in patients psyche and health-care delivery system.

In accordance with other studies,[7] this study found a significant association between better adherence and older age possibly because young people are reluctant to accept lifelong drug intake for an asymptomatic condition.

Similar to a study in Eastern Nepal,[8] a significant association was revealed between literacy status and adherence.

In agreement with other studies,[2] the increased interval between onset of present symptom and diagnosis of hypertension/initiation of antihypertensive treatment was significantly associated with adherence. Probably, patients taking antihypertensives for prolonged duration are more aware of consequences of missing pills and have greater acceptance of the disease state.

A unique finding of this study was a significant increase in adherence on prescription of the antihypertensive by a registered medical practitioner, which may be attributed to inadequate therapeutic modulation or improper explanation regarding the necessity of continuing antihypertensives lifelong by unqualified (unregistered) practitioners.

Similar to other studies,[9] advice with a proper explanation regarding the necessity of regular intake of drugs had a strong association with adherence.

Contrary to other studies,[3] high medical cost and adherence showed significant association. Doubt of the efficacy of low-cost medicines provided at the government hospitals may account for refusal to prolonged medication.

Unlike other studies, gender[10] and number of comorbidities[3] reported no significant association with adherence, whereas, similar to other reports,[3] drug adherence was not significantly different between urban and rural settings.

In spite of certain limitations (inability to establish a relationship between nonadherence and long-term outcome and survival, single hospital study, recall, and social desirability bias), the strength of the study lies in cross-checking information from the available caregivers along with interviewing the patients.

Factors such as advanced age, higher literacy rate, increased duration of antihypertensive treatment, accessibility to the registered medical practitioner, and adequate explanation by health-care providers regarding the necessity of regular intake of medicine are of utmost importance for good adherence to prescribed drugs. To the best of our knowledge, this is one of the very few studies that explored antihypertensive drug adherence of stroke patients admitted at a tertiary care government hospital in eastern India and projected potential determinants that deserve further evaluation in future studies.


We express our sincere gratitude to Dr. Donald E. Morsiky for granting permission to use the Morisky, Green, and Levine Adherence Scale and Professor Dr. Abhijit Hazra for his valuable suggestion. We would like to extend our heartfelt gratitude to our patients and their family members for their kind co-operation.

Financial support and sponsorship

This study was financially supported by Short-Term Studentship ICMR-2019.

Conflicts of interest

There are no conflicts of interest.

   References Top

Dalal PM, Malik S, Bhattacharjee M, Trivedi ND, Vairale J, Bhat P, et al. Population-based stroke survey in Mumbai, India: Incidence and 28-day case fatality. Neuroepidemiology 2008;31:254-61.  Back to cited text no. 1
Mekonnen HS, Gebrie MH, Eyasu KH, Gelagay AA. Drug adherence for antihypertensive medications and its determinants among adult hypertensive patients attending in chronic clinics of referral hospitals in Northwest Ethiopia. BMC Pharmacol Toxicol 2017;18:27.  Back to cited text no. 2
Nau DP. Proportion of Days Covered (PDC) as a Preferred Method of Measuring Medication Adherence. Springfield, VA: Pharmacy Quality Alliance; 2012.  Back to cited text no. 3
Uchmanowicz B, Jankowska EA, Uchmanowicz I, Morisky DE. Self-reported medication adherence measured with morisky medication adherence scales and its determinants in hypertensive patients aged≥60 years: A systematic review and meta-analysis. Frontiers Pharmacol 2019;10:168.  Back to cited text no. 4
Ray BK, Hazra A, Ghosal M, Banerjee T, Chaudhuri A, Singh V, et al. Early and delayed fatality of stroke in Kolkata, India: Results from a 7-year longitudinal population-based study. J Stroke Cerebrovasc Dis 2013;22:281-9.  Back to cited text no. 5
Wetzels GE, Nelemans P, Schouten JS, Prins MH. Facts and fiction of poor compliance as a cause of inadequate blood pressure control: A systematic review. J Hyper 2004;22:1849-55.  Back to cited text no. 6
Smith EO, Curb JD, Hardy RJ, Hawkins CM, Tyroler HA. Clinic attendance in the hypertension detection and follow-up program. Hypertension 1982;4:710-5.  Back to cited text no. 7
Bhandari B, Bhattarai M, Bhandari M, Ghimire A, Pokharel PK, Morisky DE. Adherence to antihypertensive medications: Population based follow up in Eastern Nepal. J Nepal Health Res Counc 2015;13:38-42.  Back to cited text no. 8
Wang L. Physician-related barriers to hypertension management. Med Princ Pract 2004;13:282-5.  Back to cited text no. 9
Yassine M, Al-Hajje A, Awada S, Rachidi S, Zein S, Bawab W, et al. Evaluation of medication adherence in Lebanese hypertensive patients. J Epidemiol Glob Health 2016;6:157-67.  Back to cited text no. 10


  [Table 1], [Table 2]


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