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Table 1 Study characteristics

From: Medication adherence influencing factors—an (updated) overview of systematic reviews

Study

Search period

Inclusion criteria (patients and medication marked in italics)

Explorative systematic reviews

Aziz 2016

Not limited to February 2015

Patients with chronic conditions and different payment schemes

Human adults

Published in English

Evaluation of the effect of medication cost or method of payment on medication adherence

Clear description of study population and methodological approach

Only studies without a adherence intervention

Only randomized controlled trials, cross-sectional, longitudinal and observational/prospective or retrospective cohort studies

Only original research (review articles, thesis, commentaries, editorial letters, and case studies were excluded)

Broekmans 2008

Not limited to December 2006

Adult patients with chronic non-malignant pain

Adult patients with prescribed pain medication

Original research

Chen 2015

January 1990 to September 2013

Patients after acute coronary syndrome getting secondary prevention pharmacotherapy

Humans aged ≥ 18 years

Subjects hospitalized for an acute coronary syndrome

Prescription of at least one specified evidence-based medication after hospital discharge (beta-blocker, lipid-lowering agents, antiplatelet agents, ACEIs or ARBS)

Report of medication usage after hospital discharge

Measuring medication adherence and reporting its method of measurement

Only secondary adherence/non-adherence (not initiation)

At least 2 months follow-up

Specific follow-up time for calculating medication adherence

Calculation of medication adherence of patients with at least one filled prescription for the medication of interest during the follow-up time

All study designs

Only original research

Only analysis of the original study population

Publication in a peer-reviewed journal

Daley 2012

Not limited to January 2012

Patients with Parkinson

All ranges and duration of anti-parkinsonian treatments

All age ranges

Published in English

Presenting quantitative/qualitative data

Gourzoulidis 2017

Not limited to NR

Patients with diabetes mellitus or heart failure

Different study types including retrospective, longitudinal observational cohort or cross-sectional studies (no reviews, meta-analyses, editorials, comments or letters to the editor)

Co-payment-interventions (introduction of co-payments or increases/decreases in existing co-payments)

Studies assessing the impact of co-payments on adherence

Exclusion of other types of cost-sharing, co-insurance, deductibles or caps

Exclusion of economic evaluations and treatment interventions

Only English and full-text published articles

Jaam 2017

Not limited to May 2016

Adults patients (≥ 18 years old) with diabetes mellitus type 1 or 2 living in the Middle East and North African region

Only original research reporting qualitative or quantitative data

Studies investigating factors associated with medication adherence

Patients receiving anti-diabetic medication

Krueger 2015

Not limited to March 2014

Adult patients with chronic heart failure

Studies analysing the relationship between age and medication adherence

Studies relating to pharmacological adherence

Only original research

Poor quality studies were excluded

Published in every language

Maimaris 2013

Not limited to May 2013

Adult population (general or on hypertension treatment)

Studies reporting on effects of national or regional (not individual or organisational levels) health system level arrangements (interventions, policies, or programs) on hypertension control

Adult population, including general population, population on treatment and population with specific comorbidities

Quantitative studies

Quantitative studies must report a measure of association between health system arrangement and at least one hypertension outcome of interest

Different study types including controlled trials, cohort studies and cross-sectional studies

Published in every language

Mann 2014

Not limited to March 2013

Adult patients with cardiovascular-related chronic conditions (coronary artery disease, hypertension, diabetes, hypercholesterolemia, cerebrovascular disease)

Studies assessing drug insurance (intervention) against a comparator group (including various cost-sharing strategies like co-payments, fixed co-payments, co-insurance, deductibles, caps, coverage gaps)

Different study designs including randomized controlled trials, non-randomized controlled trials, before-after-studies, interrupted time series

Studies reporting on medication adherence, clinical outcomes, quality of life, health care utilization or costs

Studies not focussing on health policy, value-based insurance or reference based pricing

English published

Mathes 2014(a)

Not limited to December 2012

Hepatitis C-infected patients

Adult patients with hepatitis C

Patients getting medication regimes containing ribavirin

Every study type with quantitative measure of patient implementation adherence

Studies analysing potential adherence influencing factor/s

Studies conducted in WHO-mortality Stratum A (very low child mortality and low adult mortality)

Published in English or German

Mathes 2014(b)

Not limited to December 2012

Patients taking oral anticancer agents

Patients ≥ 18 years old with malignant neoplasms

Patients taking oral anticancer agents

Studies analysing potential adherence influencing factor/s

Every study type with quantitative patient adherence measure (no interventional trials)

Studies not exclusively referring to intentional non-adherence measures

Published in English or German

Oosterom-Calo 2013

Not limited to August 2010

≥ 50% heart failure patients

Quantitative results were reported

Studies of at least fair quality

Evaluations of interventions were not the main purpose

No descriptive study

No review paper

Published in English

Pasma 2013

Not limited to February 2011

Inflammatory arthritis patients

Used a reproducible definition or validated instrument to measure adherence

Provided a statistical measure to reflect the strength of the association between the determinant and adherence

 No letters, editorials, reviews, RCTs, case reports, qualitative studies and opinion articles

Verbrugghe 2012

NR

Oral anti-cancer drugs

Age ≥ 18

Strong or moderate methodological quality

Written in English, French, German or Dutch

Original research articles published between 1990 and April 2012

Studies not conducted in developing countries

All study designs

Focused systematic reviews

Alsabbagh 2014

Not limited to February 2012

Patients taking antihypertensive drugs

Analysis of the influence of socioeconomic status on adherence to antihypertensive medications

All study designs

Published in English or French

Studies used electronic prescription database as source for nonadherence information

Multivariable modelling

Crawshaw 2016

January 2000 to December 2014

Adult patients (>  18 years old) after acute coronary syndrome (myocardial infarction and/or unstable angina) getting secondary prevention pharmacotherapy

Cross-sectional, retrospective cohort or prospective cohort studies

Measure of adherence to cardiac medication (antiplatelet agents, ACE inhibitors, ARBs, beta-blockers, lipid-lowering agents, calcium channel blockers or diuretics)

Standardised measurement of psychosocial variable

Assessment of strength of association between psychosocial factors and adherence

Published in English

Ghidei 2013

NR to July 2012

Older HIV-infected individuals

Only studies with control group

All study designs excluding case reports

Only studies with specified cut-off for adherence (≥ 80%)

Only studies not focussing on psychiatric disorders

Patient in the older classification aged > 45 years

Initial use of antiretroviral therapy at or after 1996

Participations actually on antiretroviral therapy

Participations without substance abuse

Peer-reviewed articles

Only original research

Hiko 2012

January 1997 to December 2011

Adults living with HIV/AIDS

Adult patients (aged ≥18 years) living with HIV/AIDS

Patients receiving antiretroviral therapy

Patients living in developed and developing countries

Studies identifying determinants of non-compliance regarding antiretroviral therapy (socioeconomic-related, health service-related, psychosocial- and behavioural-related and clinical-related outcome measures)

Quantitative evidence from observational analytic epidemiological studies (including prospective and retrospective cohort studies, case-control and comparative cross-sectional studies)

Published in English

Lewey 2013

NR to 04/2010

Patients receiving statin therapy

Studies evaluating adherence to statin therapy and reporting gender, race or ethnicity as a predictor of adherence

Studies using univariable or multivariable analysis

Studies reporting quantitative measures of adherence

Only original data

Studies reporting adherence to statin therapy and another medication were also included

Nachega 2015

January 1980 to September 2014

Patients receiving antiretroviral therapy

Every study design

Patients living with HIV

Patients receiving antiretroviral therapy

Studies assessing treatment adherence via objective or self-reporting measures

Studies considering employment as a possible adherence influencing factor

Sinnott 2013

1946 to September 2012

Participants received healthcare from a public insurance scheme

Comparator group was the same population/similar population who either did not pay co-payments or experienced no increase in co-payment

The intervention was co-payment; either an increase in an existing co-payment or the introduction of a co-payment (no other types of cost-sharing, for example, co-insurance)

Studies included were randomised controlled trials, controlled before and after studies, interrupted time series designs, repeated measures designs, and cohort designs

  1. NR Not Reported