Variation in medication adherence across patient behavioral segments: a multi-country study in hypertension

Figures & data

Figure 1 Respondents by MARS-5 score.

Abbreviation: MARS-5, Medication Adherence Report Scale-5.

Table 1 Descriptive statistics, n=353 patients

Categorical variables	Frequency	Percentage
Dependent variable
Perfect adherence	120	34
Country
UK	50	14
Germany	51	14
Italy	121	34
Spain	131	37
Other reasons for lack of adherence
Cost	21	6
Had side effect	28	8
Avoid side effects	35	10
Don’t think it is effective	7	2
Got better	39	11
Demographic categorical variables
Employed	191	54
Some college	169	48
Numerical variables	Mean	Standard deviation
MARS-5
Alter dose	4.48	0.87
Forget to take	4.22	0.89
Stop taking	4.50	0.97
Decide to miss out	4.48	0.93
Take less than instructed	4.52	0.97
Age in years	52.03	12.69

Abbreviation: MARS-5, Medication Adherence Report Scale-5.

Figure 2 Percentage with perfect adherence by cluster.

Abbreviations: IPH, internal control/positive emotion/high agency; EPL, external control/positive emotion/low agency; EPH, external control/positive emotion/high agency; IPL, internal control/positive emotion/low agency; INH, internal control/negative emotion/high agency; ENH, external control/negative emotion/high agency; ENL, external control/negative emotion/low agency; INL, internal control/negative emotion/low agency.

Table 2 Distribution of behavioral clusters and the underlying domains, n=353 patients

	Percentage
Domain
Internal control orientation	50
Positive emotion	72
High agency	64
Behavioral cluster
IPL	12
IPH	25
EPL	10
ENL	7
INL	7
INH	6
ENH	8
EPH	25

Abbreviations: IPL, internal control/positive emotion/low agency; IPH, internal control/positive emotion/high agency; EPL, external control/positive emotion/low agency; ENL, external control/negative emotion/low agency; INL, internal control/negative emotion/low agency; INH, internal control/negative emotion/high agency; ENH, external control/negative emotion/high agency; EPH, external control/positive emotion/high agency.

Table 3 Probit regression output

	Demographic variables	Demographics + concerns	Demographics + CoMac clusters	Demographics + concerns + CoMac clusters
Age in years	−0.0025 (0.0067)	−0.0089 (0.0072)	−0.0085 (0.0071)	−0.0153** (0.0077)
Employed	−0.3792** (0.1553)	−0.3919** (0.1630)	−0.4077** (0.1618)	−0.4209** (0.1694)
Some college	−0.2252 (0.1451)	−0.2120 (0.1525)	−0.2206 (0.1537)	−0.1983 (0.1609)
UK	0.3485 (0.2359)	0.4646* (0.2487)	0.2126 (0.2497)	0.3109 (0.2629)
Germany	0.1983 (0.2353)	0.2276 (0.2434)	0.0931 (0.2462)	0.0967 (0.1930)
Spain	0.1102 (0.1687)	0.1694 (0.1762)	-0.1526 (0.1842)	−0.1226 (0.1930)
Got better		−0.9597*** (0.3184)		−1.020*** (0.3383)
Cost		–0.2563 (0.3495)		−0.2969 (0.3625)
Side effects too severe		−1.0485 (0.4792)		−0.9970* (0.5146)
Avoid anticipated side effects		−0.8340** (0.3828)		−0.7674* (0.3965)
Don’t think it helps		0.6710 (0.6028)		0.6932 (0.6331)
IPL			−0.4566* (0.2608)	−0.5998** (0.2701)
IPH			0.3144 (0.1991)	0.2482 (0.2065)
EPL			−0.0134 (0.2636)	0.0012 (0.2797)
ENL			−0.9081** (0.3620)	−0.8878** (0.3866)
INL			−1.1988*** (0.3919)	−1.1893*** (0.4208)
INH			−0.3908 (0.3355)	−0.3544 (0.3524)
ENH			−0.5688* (0.3066)	−0.6166* (0.3229)
Constant	−0.0974 (0.3979)	0.3801 (0.4345)	0.5066 (0.4386)	1.0457* (0.4830)
Pseudo R^2	0.0282	0.1088	0.0999	0.1703

Notes:

* Significant at the 0.1 level;

** significant at the 0.05 level;

*** significant at the 0.01 level. Standard error indicated in parentheses.

Abbreviations: IPL, internal control/positive emotion/low agency; IPH, internal control/positive emotion/high agency; EPL, external control/positive emotion/low agency; ENL, external control/negative emotion/low agency; INL, internal control/negative emotion/low agency; INH, internal control/negative emotion/high agency; ENH, external control/negative emotion/high agency.

Table 4 Marginal effects of binary variables

Variable	Change in probability of being perfectly adherent
Had severe side effects	−0.32
Avoiding side effects	−0.30
INL versus EPH	−0.28
Stopped medicine because I got better	−0.28
ENL versus EPH	−0.23
ENH versus EPH	−0.15
Employed	−0.15
IPL versus EPH	−0.11

Abbreviations: IPL, internal control/positive emotion/low agency; INL, internal control/negative emotion/low agency; EPL, external control/positive emotion/low agency; EPH, external control/positive emotion/high agency.