Validation of the General Medication Adherence Scale in Saudi Patients With Chronic Diseases.

Atta Abbas Naqvi,Abdul Haseeb,Hani Saleh Faidah,Dhafer Mahdi Alshayban,Syed Azizullah Ghori,Mansour Adam Mahmoud,Mohamed Azmi Hassali

doi:10.3389/fphar.2019.00633

Abstract

Objective: The aim was to validate the General Medication Adherence Scale (GMAS) (English version) in Saudi patients with chronic disease. Methods: A month-long study was conducted in the out-patient department of tertiary care hospitals in three cities of Saudi Arabia that collected data from a randomized sample of Saudi patients with chronic disease. The study aimed to achieve an item-to-subject ratio greater than 1:10. Factor analyses were conducted and fit indices calculated. Convergent, discriminant, known group, and concurrent validities were analysed. Internal consistency was determined using test–retest reliability using Cronbach’s alpha (α), McDonald’s coefficient omega (ωt), and Pearson’s correlation coefficient (ρ). Sensitivity analysis was conducted. Data were analysed through Statistical Package for Social Sciences (SPSS) version 23. The study was ethically approved (i.e., IRB-129-26/6/1439). Results: The survey gathered responses from 171 patients with a response rate of 85.5%. An item-to-subject ratio of 1:15 was achieved. Factor analysis revealed a three-factor structure with acceptable fit indices (i.e., normed fit index (NFI) = 0.93, Tucker–Lewis index (TLI) = 0.99, and comparative fit index (CFI) = 0.99), i.e., greater than 0.9. The value of root mean square error of approximation (RMSEA) was 0.01, i.e., less than 0.08. The tool established construct validity, i.e., convergent and discriminant validities. Known group and concurrent validities were also established. An α value of 0.74 and ωt value of 0.92 were reported. Test–retest reliability ρ = 0.82, p < 0.001. The tool had high sensitivity (>75%) and specificity (>80%). Conclusion: The GMAS-English was successfully validated in Saudi patients with chronic disease.

Highlights

Adherence to medication could be defined as the extent of patient concordance to prescribed medication therapy (Osterberg and Blaschke, 2005)
A month-long study was conducted in the out-patient department of tertiary care hospitals in three cities of Saudi Arabia that collected data from a randomized sample of Saudi patients with chronic disease
The General Medication Adherence Scale (GMAS)-English was successfully validated in Saudi patients with chronic disease

Summary

Introduction

Adherence to medication could be defined as the extent of patient concordance to prescribed medication therapy (Osterberg and Blaschke, 2005) It is important in evaluating treatment success as well as identifying drug-related problems (Osterberg and Blaschke, 2005; Naqvi et al, 2018a). Proper adherence ensures optimal disease outcomes and improves patient’s health status, which may be limited to clinical status but may incorporate health-related quality of life (Naqvi et al, 2017). This is vital in managing noncommunicable diseases (NCDs) that require long-term medication therapy. Most common risk factors that precipitate premature death and disability together are high body mass index, high blood pressure, and dyslipidaemia (Institute of Health Metrics and Evaluation, 2017)

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Discussion

Conclusion