Perceived need to take medication is associated with medication non-adherence in patients with rheumatoid arthritis

Figures & data

Figure 1 Participant flow chart.

Abbreviation: DMARDs, disease-modifying antirheumatic drugs.

Table 1 Sample characteristics

Variables	Number of patients providing data	Descriptives
Sociodemographic factors
Age (years)	580	62.8 (12.6)
Female	580	396 (68.3%)
Living with others	571	458 (80.2%)
High education#	571	106 (18.6%)
Currently employed or studying	552	216 (39.1%)
Clinical factors
Disease duration (years)	556	14 (8–22)
Number of DMARDs used
One DMARD	476	307 (64.5%)
Two DMARDs	476	149 (31.3%)
Three DMARDs	476	20 (4.2%)
Route of DMARD administration
Oral‡	476	272 (57.1%)
Parenteral§	476	296 (62.2%)
Rheumatoid factor (positive)װ	332	260 (78.3%)
Anti-CCP (positive)װ	284	199 (70.1%)
RADAI disease activity (0–10)¶	493	2.7 (1.9)
VAS pain score (0–100 mm)¶	550	30.8 (22.4)
HAQ-DI (0–3)¶	563	1.1 (0.8)

Notes: Data are means (standard deviation), medians (interquartile range), or numbers (%).

# High education means having at least a bachelor or master degree.

‡ Azathioprine, hydroxychloroquine, leflunomide, methotrexate, predinosone/predinsolone, or sulfasalazine.

§ Adalimumab, aurothiomalate, methylprednisolone, etanercept, methotrexate, abatacept, infliximab, tocilizumab, or rituximab.

װ For descriptive purposes only, so not included in further analysis.

¶ Higher scores indicate more disease activity/pain/disability.

Abbreviations: DMARDs, disease-modifying antirheumatic drugs; Anti-CCP value, anti-cyclic citrullinated peptide antibody; RADAI, Rheumatoid Arthritis Disease Activity Index; VAS, Visual Analog Scale; HAQ-DI, Health Assessment Questionnaire Disability Index.

Table 2 Psychological factors

Variables	Number of patients providing data	Descriptives
Beliefs about medication
Necessity beliefs (5–25)#	536	19.9 (3.5)
Concerns beliefs (5–25)#	535	14.3 (3.6)
Necessity–concerns differential (−20 till +20)‡	527	5.6 (4.7)
Overuse beliefs (4–20)#	546	10.3 (2.5)
Harm beliefs (4–20)#	542	10.2 (2.5)
Attitudinal profiles: Skeptical	527	14 (2.7%)
Indifferent	527	25 (4.7%)
Ambivalent	527	244 (46.3%)
Accepting	527	244 (46.3%)
ICQ illness cognitions (6–24)#
Helplessness	542	11.7 (4.2)
Acceptance	544	17.8 (3.8)
Perceived benefits	538	14.2 (4.5)
UVR self-efficacy (1–5)#
Pain	570	3.6 (0.8)
Physical functioning	566	3.8 (1.1)
Symptoms	559	3.9 (0.8)
HADS anxiety/depression (0–42)#	567	9.3 (6.5)

Notes: Data are means (standard deviation) or numbers (%).

# Higher scores indicate stronger beliefs, more helplessness/acceptance/perceived benefits, stronger self-efficacy concerning pain/physical functioning/symptoms, and more anxiety and depression.

‡ Differential = necessity score minus concerns score. Positive score means that necessity beliefs about medication are stronger than concern beliefs about medication.

Abbreviations: ICQ, Illness Cognition Questionnaire; UVR, Arthritis Self-Efficacy Scale; HADS, Hospital Anxiety and Depression Scale.

Figure 2 Percentage of non-adherent patients per BMQ score range.

Abbreviation: BMQ, Beliefs about Medicines Questionnaire.

Table 3 Associations between beliefs about medication and CQR non-adherence

BMQ constructs	CQR non-adherence, OR (95% CI)
	Unadjusted: Step 1 (n=524–543)	Adjusted: Step 2* (n=332–344)	Adjusted: Step 3# (n=297–307)
Necessity beliefs	0.9 (0.8–0.9)‡	0.8 (0.8–0.9)‡	0.8 (0.8–0.9)‡
Concerns beliefs	1.0 (0.9–1.0)	1.0 (0.9–1.1)	1.0 (0.9–1.1)
Necessity–concerns differential	0.9 (0.9–1.0)‡	0.9 (0.9–1.0)‡	0.9 (0.9–1.0)‡
Overuse beliefs	1.1 (1.0–1.1)	1.1 (1.0–1.2)§	1.1 (1.0–1.2)
Harm beliefs	1.0 (0.9–1.1)	1.1 (1.0–1.2)	1.1 (0.9–1.2)
Attitudinal profilesװ
Skeptical	2.5 (0.9–7.2)	1.8 (0.5–5.9)	1.8 (0.5–6.0)
Indifferent	3.9 (1.7–8.9)‡	5.0 (1.3–19.3)§	5.3 (1.1–25.8)§
Ambivalent	0.8 (0.5–1.2)	0.8 (0.5–1.4)	0.7 (0.4–1.4)
Accepting	0.8 (0.6–1.2)	0.9 (0.5–1.5)	0.9 (0.5–1.7)

Notes:

* In Step 2, models were adjusted for age, sex, living with others (yes/no), high education (yes/no), currently employed or studying (yes/no), disease duration, n DMARDs used, route of DMARD administration, disease activity (RADAI), and pain (VAS).

# In Step 3, models were adjusted for the same factors as in Step 2, and additionally for illness cognitions (ICQ), self-efficacy (UVR), and anxiety/depression (HADS). The HAQ was left out as potential confounder due to multicollinearity with the UVR physical functioning scale.

‡ P≤0.01,

§ P≤0.05.

װ Reference group = “rest of the patients.” So, for example, the odds for being non-adherent to medication is bigger for patients with a skeptical attitude toward medication compared with patients with a non-skeptical attitude toward medication.

Abbreviations: CQR, Compliance Questionnaire Rheumatology; BMQ, Beliefs about Medicines Questionnaire; OR, odds ratio; CI, confidence interval; DMARD, disease-modifying antirheumatic drug; RADAI, Rheumatoid Arthritis Disease Activity Index; VAS, Visual Analog Scale; ICQ, Illness Cognition Questionnaire; UVR, Arthritis Self-Efficacy Scale; HADS, Hospital Anxiety and Depression Scale; HAQ, Health Assessment Questionnaire; n DMARDs, number of disease-modifying antirheumatic drugs.

Table S1 Details of used questionnaires (except beliefs and adherence)

Secondary outcome measure	Questionnaire	Description
Rheumatoid arthritis (RA) disease activity	Rheumatoid Arthritis Disease Activity Index (RADAI)^Citation2	Five items, measuring global disease activity/pain, current duration of morning stiffness, and current tender joints. Score range: 0–10, with higher scores indicating more disease activity
Patient’s usual abilities in past week	Health Assessment Questionnaire Disability Index (HAQ-DI)^Citation3	Twenty items, measuring eight dimensions of functioning (dressing and grooming, arising, eating, walking, hygiene, reaching, gripping, and common daily activities). Greater than or equal to six dimensions need a valid score to obtain the total score. Score range: 0–3, with higher scores indicating more disability. Note that we took aids and devices into account in calculating the HAQ-DI score
Pain severity	HAQ Visual Analog Scale (VAS)^Citation3,Citation4	Scale range: 0 mm (no pain) to 100 mm (unbearable pain)
Illness cognitions	Illness Cognition Questionnaire (ICQ)^Citation5	Three subscales of six items each, measuring “helplessness” as a way of emphasizing the aversive meaning of a disease, “acceptance” as a way to diminish this aversive meaning, and “perceived benefits” as a way of adding a positive meaning to a disease. Score range: 6–24, with higher scores indicating more helplessness, acceptance, and perceived benefits
Self-efficacy	Arthritis Self-Efficacy Scale (UVR)^Citation6,Citation7	Measures the patient’s perceived ability to perform specific behaviors aimed at controlling disability. The UVR has three subscales: self-efficacy related to physical function (eight items), to coping with pain (five items), and to coping with other symptoms associated with arthritis (such as depression and fatigue, six items) Score range: 1–5, with higher scores indicating stronger self-efficacy
Anxiety and depression	Hospital Anxiety and Depression Scale (HADS)^Citation8	14 items, total score range: 0–42, with higher scores indicating a higher degree of anxiety/depression The HADS has two subscales, one for anxiety and one for depression, with seven items per scale. Subscale score range: 0–21; subscale scores higher than 8 are indicative of anxiety or depression

Note: All items in a questionnaire need a valid answer to obtain a total score, unless mentioned otherwise.

Table S2 The contribution of single, psychological factors to associations between beliefs about medication and CQR non-adherence (corrected for demographic and clinical factors)

	CQR non-adherence, OR (95% CI)
	Necessity beliefs	Concern beliefs	NC differential	Overuse beliefs	Harm beliefs	Attitudinal profiles
						Skeptical	Indifferent	Ambivalent	Accepting
Basic, adjusted model (including demographic and clinical variables)*	0.8 (0.8–0.9)#	1.0 (0.9–1.1)	0.9 (0.9–1.0)#	1.1 (1.0–1.2)‡	1.1 (1.0–1.2)	1.8 (0.5–5.9)	5.0 (1.3–19.3)‡	0.8 (0.5–1.4)	0.9 (0.5–1.5)
+ ICQ helplessness§	–	–	–	–	–	–	–	0.9 (0.5–1.6)	0.8 (0.5–1.3)
+ ICQ acceptance||	–	–	–	–	–	–	–	0.6 (0.4–1.1)	1.1 (0.6–1.9)
+ ICQ perceived benefits	–	–	–	–	–	–	6.9 (1.5–32.2)‡	0.7 (0.4–1.2)	1.0 (0.6–1.6)
+ UVR self-efficacy pain	–	–	–	–	–	–	–	–	–
+ UVR self-efficacy physical functioning	–	–	–	–	–	–	–	–	–
+ UVR self-efficacy symptoms	–	–	–	–	–	–	–	–	–
+ HADS anxiety/depression	–	–	–	–	–	–	–	–	–

Notes:

* Each of these models is adjusted for age, sex, living with others (yes/no), high education (yes/no), currently employed or studying (yes/no), disease duration, n DMARDs used, route of DMARD administration, disease activity (RADAI) and pain (VAS).

# P≤0.01.

‡ P≤0.05.

§ Basic, adjusted model (corrected for demographic and clinical variables) and ICQ helplessness.

|| Basic, adjusted model (corrected for demographic and clinical variables) and ICQ acceptance (etc). Data are shown as CQR non-adherence, OR (95% CI).

Abbreviations: CQR, Compliance Questionnaire Rheumatology; OR, odds ratio; NC, necessity concerns; ICQ, Illness Cognition Questionnaire; UVR, Arthritis Self-Efficacy Scale; HADS, Hospital Anxiety and Depression Scale; RADAI, Rheumatoid Arthritis Disease Activity Index; VAS, Visual Analog Scale; n DMARDs, number of disease-modifying antirheumatic drugs.

FransenJLangeneggerTMichelBAStuckiGFeasibility and validity of the RADAI, a self-administered rheumatoid arthritis disease activity indexRheumatology (Oxford)200039332132710788543

 PubMed Web of Science ®Google Scholar

BruceBFriesJFThe Stanford Health Assessment Questionnaire: dimensions and practical applicationsHealth Qual Life Outcomes200312012831398

 PubMedGoogle Scholar

PriceDDBushFMLongSHarkinsSWA comparison of pain measurement characteristics of mechanical visual analogue and simple numerical rating scalesPain1994562172268008411

 PubMed Web of Science ®Google Scholar

EversAWKraaimaatFWvan LankveldWJongenPJJacobsJWBijlsmaJWBeyond unfavorable thinking: the illness cognition questionnaire for chronic diseasesJ Consult Clin Psychol20016961026103611777106

 PubMed Web of Science ®Google Scholar

LorigKChastainRLUngEShoorSHolmanHRDevelopment and evaluation of a scale to measure perceived self-efficacy in people with arthritisArthritis Rheum198932137442912463

 PubMed Web of Science ®Google Scholar

RiemsmaRPTaalERaskerJJGroup education for patients with rheumatoid arthritis and their partnersArthritis Rheum200349455656612910564

 PubMed Web of Science ®Google Scholar

ZigmondASSnaithRPThe hospital anxiety and depression scaleActa Psychiatr Scand19836763613706880820

 PubMed Web of Science ®Google Scholar