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European Journal of Public Health, Vol. 23, No. 3, 433–440
ß The Author 2011. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.
doi:10.1093/eurpub/ckr137 Advance Access published on 27 September 2011
.........................................................................................................
Socio-economic determinants of early discontinuation
of anti-depressant treatment in young adults
Karolina Andersson Sundell1, Margda Waern2, Max Petzold1, Mika Gissler1,3
1 Nordic School of Public Health, Gothenburg, Sweden
2 Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg,
Sweden
3 National Institute for Health and Welfare, Helsinki, Finland
Correspondence: Karolina Andersson Sundell, Address: Nordic School of Public Health, PO Box 12133, SE 402 42
Gothenburg, Sweden, Tel: +46 31 693927, Fax: +46 31 691777, e-mail: [email protected]
Background: Early discontinuation of anti-depressant treatment is common. This study analysed whether
socio-economic factors influence early discontinuation among new anti-depressant users aged 20–34 years.
Methods: Our study population included all Swedes aged 20–34 years who purchased anti-depressants in 2006
and had not purchased such drugs in the preceding 6 months (n = 25 003). We obtained prescription data from the
Swedish Prescribed Drug Register. Information about demographic and socio-economic factors (country of birth,
marital status, household size, education level, occupation, income and social assistance) was collected from
Statistics Sweden by record linkage. We defined early discontinuation as filling only one anti-depressant prescription within a 6-month period. We used multiple logistic regression analysis to analyse the socio-economic factors
associated with early discontinuation. Results: We identified 6536 individuals (26.1%) as early discontinuers. Early
discontinuation was less common among women [odds ratio (OR) = 0.82; 95% confidence intervals (CI) 0.75–0.87]
and in those with at least two years of higher education (OR = 0.71; 95% CI 0.61–0.83), whereas it was more
common among those born outside Sweden (OR = 1.76; 95% CI 1.48–2.10) and those who received social
assistance (OR = 1.26; 95% CI 1.11–1.44). Compared with selective serotonin re-uptake inhibitors, SSRI, early discontinuation was more common among individuals who started treatment with a tri-cyclic anti-depressant, TCA,
(OR = 2.58; 95% CI 2.24–2.98) or an anti-depressant other than SSRIs, TCAs or selective serotonin-norepinephrine
re-uptake inhibitors/norepinephrine (noradrenaline) re-uptake inhibitors (OR = 2.90; 95% CI 2.05–4.10).
Conclusion: Early discontinuation occurred more commonly among social assistance recipients and those with
immigrant background, suggesting that those groups might require greater support when initiating
anti-depressant therapy.
.........................................................................................................
Introduction
nti-depressants are used for several indications although
1,2
To increase the likelihood
of successful treatment outcomes and reduce risk for relapse,
current treatment guidelines recommend a treatment period that
continues at least 6 months after determining that the treatment is
effective.3 Early discontinuation of anti-depressants indicates
Amost commonly for depression.
suboptimal use and might affect the duration and recurrence of
depression11,13,4
However, early discontinuation is common, ranging from 15% to
over 55%.2,5–19 Indeed, many earlier studies reported that over
one-fourth of all new users discontinue anti-depressants
early.2,7,10,12–18,20
Previous international studies suggested that groups characterized
by low education level, low income, unemployment, disability
434
European Journal of Public Health
pensioners or born abroad or with other citizenship than the
country where the study was conducted are more likely to discontinue treatment early.4,5,12,13 Compared to clinical characteristics,
the relative impact of socio-economic factors differs among
studies.5,12,14 However, several studies identified foreign
background as a strong predictor of early discontinuation,
sometimes as strong as clinical predictors.4,14 Few studies have
examined how prescriber characteristics, e.g. whether the prescription was issued by a general practitioner (GP) or a psychiatrist,
influence early discontinuation. However, a Danish study reported
that prescriber characteristics are less important than clinical and
socio-economic characteristics.12 However, some studies have only
included anti-depressants prescribed by GPs.5,10,18 Furthermore,
previous reports about differences in early discontinuation rates by
age are inconsistent. Some studies noted age differences, but others
did not.5,12,14
Sick-listings and disability pensions related to mental health
problems, especially depression, have increased among Swedish
adults aged 35 years.21 The age span from late teens to late 20s
or early 30s is sometimes termed ‘emerging adulthood’, a relatively
new phenomenon resulting from increased incidence of
postsecondary education and postponement of family formation
and childbearing.22 Some commonly used socio-economic
indicators, e.g. income level, might be less sensitive during
emerging adulthood, a period characterized by transition.22
Parental background likely impacts the health and health
behaviour of young adults and increases the need for information
about their parents’ history. Most previous studies investigating
early discontinuation assessed only whether individuals were born
outside the country where the study was conducted or had another
citizenship.4,5,12,13 Therefore, we sought to examine whether early
discontinuation of anti-depressants in Swedish adults <35 years of
age linked with demographic and socio-economic factors accounting
also for parental country of birth.
Our population-based national register study analysed whether
early discontinuation among new anti-depressant users aged
20–34 years associated with socio-economic factors, prescriber characteristics, anti-depressant type and concurrent use of other
medicines in Sweden. We also investigated whether socio-economic
factors differed among anti-depressant users aged 20–34 years and a
sample-based reference population taken from the general
population in the same age group.
Methods
Study population and study period
The study population encompassed all Swedes aged 20–34 years who
filled at least one anti-depressant prescription between 1 January and
30 June 2006 and had not filled an anti-depressant prescription in
the preceding 6 months (n = 25 003). The first filled prescription in
2006 represents the index prescription and the index date for each
individual. The study period began on 1 January 2006 and ended on
31 December 2006.
To compare background characteristics, we randomly selected a
reference population of 500 000 individuals aged 20–34 years who
filled no anti-depressant prescriptions in 2006 and lived in Sweden
on 1 January 2006.
Data
The Swedish Prescribed Drug Register, SPDR, provided information
about all prescription drugs purchased by the study population
between 1 July 2005 and 31 December 2006. The SPDR includes
information about the purchased drug and the unit that issued the
prescription.23 Medicines were classified using the Anatomical
Therapeutical Classification system (ATC).24 Patients can purchase
a maximum 90-day supply of continuous use medicines included in
the Swedish Pharmaceutical Benefits Scheme per fill.25 When
initiating treatment, individuals can purchase either a 90-day
supply or a start package that includes a maximum supply of 30
days. Around half of our study population purchased a start package
on the index date.26
We defined anti-depressants as substances included in ATC-group
N06A. Anti-depressant types included tricyclic anti-depressants
(TCA) (ATC-group N06AA); selective serotonin re-uptake
inhibitors (SSRI) (ATC-group N06AB); serotonin-norepinephrine
re-uptake inhibitors and norepinephrine (noradrenaline) reuptake
inhibitors (SNRI/NRI) (ATC-codes N06AX21, N06AX16,
N06AX18) and all other anti-depressant medications.
Characteristics of the healthcare facility that issued the index prescription included type of care facility (primary/ambulatory care,
specialized or hospital care and other) and sphere of activity
(primary care, general psychiatry, other psychiatry, occupational
health services, internal medicine, neurology, pain care, oncology
and others).
We defined concurrent use of other prescription medications as at
least one non-anti-depressant prescription filled within the 180 days
following the index date. We calculated the total number of
concurrent drugs purchased during that time period. In addition,
we classified concurrent use of specific medicines such as
anti-diabetic drugs (A10); drugs for acid-related disorders (A02B);
anti-hypertensive drugs (C03, C07-C09); beta-blockers (C07);
anti-acne preparations (D10A); oral contraceptives (G03A);
thyroid therapy (H03A); antibiotics (J01); analgesics (M01 and
N02); anti-migraine drugs (N02C); opioids (N02A); codeine
(N02AA59); tramadole (N02AX02); anti-epileptics (N03A);
anti-psychotics (N05A); sedatives (N05B); hypnotics (N05C) and
anti-asthma drugs (R03A and R03B).
We collected socio-economic data from both the longitudinal
integration database for health insurance and labour market
studies (LISA) and the Total Population Register. We grouped
marital status (defined as the marital status recorded on 31
December 2006) into four categories: single, married (including
registered partnership for same-sex couples), divorced and widow/
widower. We also grouped country of birth into four categories: (i)
Sweden, (ii) other western industrial countries (the Nordic
countries, the 25 European Union countries [EU25]), North
America and Oceania), (iii) eastern European countries (including
those outside EU25) and the former Union of Soviet Socialist
Republics and (iv) other countries (Africa, South America and
Asia). A composite variable, denoted ‘background,’ reflected the
national origin of participants and their parents: (i) Swedish (born
in Sweden, two parents born in Sweden); (ii) born in Sweden, one
parent born outside Sweden; (iii) born in Sweden, both parents born
outside Sweden; (iv) born outside Sweden, at least one parent born
in Sweden and (v) born outside Sweden, two parents born outside
Sweden.
The number of household members and information about
whether an individual had received study allowances or unemployment benefits were assessed in 2005. We defined social assistance (a
cash benefit received in the absence of other income) at the
household level, i.e. had the individual or any other household
member received social assistance in 2005 (yes/no). Social
assistance only includes a cash benefit given to those with an
absence of other income. It does not include other benefits, e.g.
study allowances or unemployment benefits. We also recorded the
highest level of education attained at the end of the 2006 spring
term. We defined occupational status as employment/unemployment in November 2005 and also included an individual’s
occupation type (upper white-collar; lower white-collar;
blue-collar and others including armed forces, farmers, market
gardeners and forestry and related workers. Income/household
income data referred to year 2005. We used the median annual
income and an annual income <60% of the median income as
income indicators in the study population. We collected date of
Socio-economic determinants of anti-depressant discontinuation
death and migration data from the LISA-database at the end of the
study period.
Ethics approval, a prerequisite for data access, was obtained from
the regional ethics board in Gothenburg.
435
The outcome was early discontinuation of anti-depressant use
defined as no anti-depressant refills within 6 months after
index date.
socio-economic variables included sex, age (grouped in 5-year
classes), marital status, background, level of education, student
status, unemployment, socio-economic status, having received
social assistance and income <60% of the median income. We
also considered the type of anti-depressant purchased on the index
date and the sphere of activity of the health care facility where the
index prescription was issued. We analysed the data for both the
entire study population and the groups stratified by 5-year age
groups. Data analyses were carried out in SAS version 9.1 (SAS
Institute Inc, NC, USA, 2005).
Statistical analyses
Results
Outcome measures
2
We used Pearson’s -test to analyse differences between groups for
categorical variables and also between the study population and the
reference population. Means and standard deviations (SDs) were
presented for continuous variables as well as median values and
inter-quartile range if these differed. We used the Student’s t-test
to analyse differences between groups for continuous variables.
Differences where P < 0.05 were considered to be statistically
significant.
We used multiple logistic regression analysis to identify factors
associated with early discontinuation, and included variables
selected a priori with a P < 0.2 in the univariate logistic regression
analyses in the multiple logistic regression models. Independent
The study population comprised 25 003 individuals aged 20–34 years
who initiated anti-depressant use during the first 6 months of 2006.
In total, 6536 (26.1%) individuals filled one prescription only once
(table 1). A larger proportion of the early discontinuers had
completed only mandatory education or had received social
assistance, whereas a smaller proportion of the early discontinuers
had a Swedish background and higher education (2 years)
compared to those who purchased refills (table 1). Furthermore, a
smaller proportion of early discontinuers purchased an SSRI on the
index date. A smaller proportion of early discontinuers received
their index prescription in a general psychiatry setting compared
to those who filled at least two prescriptions (table 2).
Table 1 Distribution of socio-economic characteristics and type of antidepressant at baseline among individuals who discontinued
anti-depressant use early (n = 6536) and individuals who did not (n = 18 467)
Characteristic
No early discontinuation
n (%)
Early discontinuation
n (%)
P-value
Woman
Age (years)
20–24
25–29
30–34
Marital status
Unmarried
Married
Divorced or widow/widower
Number of people in the household
1
2
3–5
6 or more
Background
Born in Sweden, two parents born in Sweden
Born in Sweden, one parent born in Sweden
Born in Sweden, two parents born outside Sweden
Born outside Sweden, one or both parents born in Sweden
Born outside Sweden, two parents born outside Sweden
Highest attained education
Mandatory education (0–10 years)
Upper secondary school
Higher education < 2 years
Higher education 2 years
Activity on the labour market
Employed
Student
Received social assistance
Socio-economic status
Upper white collar worker
Lower white collar worker
Blue collar worker
Other
Disposable income < 60% of the median value
Type of anti-depressant purchased at baseline
SSRI
TCA
SNRI/NRI
Other anti-depressant
11 771 (63.8)
3930 (60.2)
<0.001
4856 (26.3)
6140 (33.3)
7471 (40.5)
1663 (25.4)
2170 (33.2)
2703 (41.4)
0.849
14 423 (78.6)
3086 (16.8)
832 (4.5)
4839 (75.2)
1222 (19.0)
378 (5.9)
<0.001
9258
2117
6668
261
(50.6)
(11.6)
(36.4)
(1.4)
3098
826
2397
142
(47.9)
(11.6)
(36.4)
(2.2)
<0.001
13 159
1840
863
63
671
(79.3)
(11.1)
(5.2)
(0.4)
(4.0)
4126
600
362
25
441
(74.3)
(10.8)
(6.5)
(0.5)
(7.9)
<0.0001
3415
8792
1574
4244
(19.0)
(48.8)
(8.7)
(23.6)
1649
3118
395
1171
(26.0)
(49.2)
(6.2)
(18.5)
<0.0001
7998 (43.7)
5006 (27.4)
3103 (17.0)
3019 (46.7)
1504 (23.3)
1532 (23.7)
<0.001
0.001
<0.001
3327
4839
5085
134
4171
(24.9)
(36.2)
(38.0)
(1.0)
(22.6)
944
1593
1866
46
1554
(21.2)
(35.8)
(41.9)
(1.0)
(23.8)
<0.001
14 519
997
2805
146
(78.6)
(5.4)
(15.2)
(0.6)
4613
822
991
110
(70.6)
(12.6)
(15.2)
(1.7)
<0.0001
Percentages of missing value are given as per cent of total for each category where available.
0.049
436
European Journal of Public Health
Table 2 Early discontinuation by characteristics of prescribing unit issuing the index prescription for individuals
who discontinued early (n = 6536) and individuals who did not (n = 18 467). Percentages of missing value are given
as percent of total for each category, where available
Characteristic
By type of care
Primary care/ambulatory care
Specialized care/Inpatient care
Other
By sphere of activity
Primary care
Psychiatry—general
Other psychiatry
Occupational health service
Internal medicine
Neurology
Pain care
Oncology
Other
No early discontinuation
(n = 18 467)
n (%)
Early discontinuation
(n = 6536)
n (%)
8640 (44.5)
8588 (44.2)
2183 (11.3)
2502 (44.7)
2430 (43.5)
2183 (11.8)
9215
5399
341
450
382
145
38
14
281
3293
1546
122
129
216
73
13
9
265
(56.7)
(33.2)
(2.1)
(2.8)
(2.4)
(0.9)
(0.2)
(0.1)
(1.7)
On average, each member of the study population used 2.0
(SD 2.1) concurrent prescription medicines (median 1). The
number was slightly lower among early discontinuers [mean 1.7
(2.0), median 1] compared to those with refills [mean 2.0 (2.2),
median 1], P < 0.001. The most commonly used medicines were
antibiotics (41.7%), sedatives (33.6%), hypnotics (32.3%) and,
among women, oral contraceptives (45.4%). The proportion of
concurrent use of sedatives (25.5% vs. 36.4%, 2 258.7, df 1,
P < 0.001), hypnotics (27.4% vs. 34.1%, 2 99.4, df 1, P < 0.001)
and oral contraceptives (41.7% vs. 46.6% of women, 2 27.7, df 1,
P < 0.001) was lower among early discontinuers compared to those
with refills. There were no major differences for the other drug
groups studied.
All selected variables met the inclusion criteria for adjusted
logistic regression analyses (table 3). We observed only minor
changes in the estimates in the adjusted model compared to the
univariate logistic regression models, although we noted some
changes for marital status and socio-economic status. In the
adjusted model, early discontinuation was more common among
those born outside Sweden with two non-Swedish parents
[odds ratio (OR) = 1.76] compared to those born in Sweden with
Swedish parents, and it was slightly elevated for those born in
Sweden with non-Swedish parents (OR = 1.20). Furthermore, early
discontinuation was more common among those receiving social
assistance (OR = 1.26), but less common among those with 2
years of higher education (OR = 0.71). Early discontinuation was
more common among those who started treatment with a TCA
(OR = 2.58) or anti-depressant other than SSRI, TCA and SNRI/
NRI (OR = 2.90) but less common when the first filled prescription
was issued by a general psychiatric health care facility (OR = 0.81).
There were no major differences in the results from the multiple
regression analyses stratified by age (5-year classes) compared to
those for the whole study population. While female sex was
associated with early discontinuation in age groups 25–29 and 30–
34 years in the unadjusted analyses, these associations were not significant in the multivariate models. In age groups 20–24 and 25–29
years, we observed no difference between Swedes and those born in
Sweden to two non-Swedish parents and for recipients of social
assistance. Furthermore, we detected no differences between those
with upper secondary school education and for those with
mandatory education only in the youngest and the oldest age
groups and for those with a higher education <2 years in the
oldest group. Early discontinuation was more common among
blue-collar workers in the oldest age group.
Women, individuals with only mandatory education, recipients of
social assistance, blue-collar and lower level white-collar workers
(58.1)
(27.3)
(2.2)
(2.3)
(3.8)
(1.3)
(0.2)
(0.2)
(4.7)
P-value
0.397
<0.001
were overrepresented in the study population when compared to
the reference population (table 4). Further, the proportion of the
youngest age group, individuals with a higher education two years or
longer and employed individuals was smaller in the study
population.
Discussion
Over one-fourth of new anti-depressant users discontinued
treatment early, suggesting suboptimal use. Early discontinuation
rates were lower among individuals who started treatment with an
SSRI and those who used sedatives and hypnotics concurrently. We
detected higher discontinuation rates among individuals born
outside Sweden with non-Swedish parents, individuals born in
Sweden with non-Swedish parents and among individuals who
received social assistance. Early discontinuation was less common
among individuals with higher education and among women.
Although some previous studies reported similar early discontinuation rates,2,5,6,8 others reported lower11 or higher7,10,12–15,18,20 rates.
However, most of these studies included a broader age span than our
study. Disparate results might be attributable to several factors, such
as different definitions of early discontinuation, whether prescribing
or dispensing data were used, age groups studied, setting (primary
care or specialized health care) and whether inclusion in the study
required a diagnosis of depression. The variation in early discontinuation rates by anti-depressant type in this study was in
accordance with that in previous studies.12,27
Being born outside Sweden with non-Swedish parents was the
most strongly associated factor with early discontinuation. Other
studies have also reported differences in early discontinuation
rates by background. In the Netherlands, being a non-western
migrant was the strongest predictor for early discontinuation in
adults aged 18 years.4 A Danish study also reported that early
discontinuation was more common among those with a foreign
citizenship.12 Olfson et al.14 reported that early discontinuation
differed by ethnic origin, i.e. it was more common among
Hispanics than whites in the USA. Thus, although studies have
used different definitions to indicate migration background, which
might influence results to some degree, all results point in the same
direction.
Our finding that early discontinuation was less common among
individuals with higher education concurs with previous
studies,5,12,14 possibly because more highly educated individuals
easier understand information about the onset of effect and the
side effects of anti-depressant treatment. A study investigating
beliefs about anti-depressants among Australian adults determined
Socio-economic determinants of anti-depressant discontinuation
437
Table 3 Results from logistic regression models analysing predictors for early discontinuation in the study population (n = 25 003), presented
as crude and adjusted ORs with 95% CIs
Predictor
Crude
OR (95% CI)
Adjusteda
OR (95% CI)
Women
Age (years)
20–24
25–29
30–34
Marital status
Unmarried
Married
Divorced or widow/widower
Background
Born in Sweden, two parents born in Sweden
Born in Sweden, one parent born in Sweden
Born in Sweden, two parents born outside Sweden
Born outside Sweden, one parent born in Sweden
Born outside Sweden, two parents born outside Sweden
Highest attained education
Mandatory education (0–10 years)
Upper secondary school
Higher education <2 years
Higher education 2 years
Socio-economic status
Upper white-collar worker
Lower white-collar worker
Blue- collar worker
Other occupation
Student
Unemployed
Social assistance
Income <60% of median income
Type of anti-depressant purchased at index date
SSRI
TCA
SNRI/NRI
Other anti-depressant
Sphere of activity of health care facility issuing the index prescription
Primary care
Psychiatry—general
Other psychiatry
Occupational health service
Internal medicine
Neurology
Pain care
Oncology
Other
0.86 (0.81–0.91)
0.82 (0.75–0.89)
1.00
1.03 (0.96–1.11)
1.06 (0.98–1.13)
1.00
1.04 (0.93–1.17)
1.00 (0.88–1.13)
1.00
1.18 (1.10–1.27)
1.35 (1.19–1.54)
1.00
1.03 (0.92–1.15)
1.10 (0.90–1.35)
1.00
1.04
1.34
1.27
2.10
1.00
1.01
1.20
1.23
1.76
(0.94–1.15)
(1.18–1.52)
(0.80–2.01)
(1.85–2.38)
(0.88–1.15)
(1.01–1.43)
(0.66–2.28)
(1.48–2.10)
1.00
0.73 (0.68–0.79)
0.52 (0.46–0.59)
0.57 (0.52–0.62)
1.00
0.85 (0.76–0.95)
0.62 (0.51–0.75)
0.71 (0.61–0.83)
1.00
1.16
1.29
1.21
0.81
0.94
1.52
1.07
1.00
1.07
1.09
1.19
0.97
1.03
1.26
1.01
(1.06–1.27)
(1.18–1.42)
(0.86–1.70)
(0.75–0.86)
(0.87–1.01)
(1.42–1.63)
(1.00–1.14)
(0.95–1.21)
(0.97–1.23)
(0.81–1.75)
(0.87–1.09)
(0.94–1.13)
(1.11–1.44)
(0.89–1.15)
1.00
2.60 (2.35–2.86)
1.11 (1.03–1.20)
2.37 (1.85–3.05)
1.00
2.58 (2.24–2.98)
1.08 (0.96–1.22)
2.90 (2.05–4.10)
1.00
0.80
1.00
0.80
1.59
1.41
0.96
1.80
2.64
1.00
0.81
0.79
0.90
1.18
0.99
0.42
1.54
2.88
(0.75–0.86)
(0.81–1.24)
(0.66–0.98)
(1.33–1.88)
(1.06–1.88)
(0.51–1.80)
(0.78–4.16)
(2.22–3.13)
(0.73–0.89)
(0.58–1.07)
(0.72–1.13)
(0.94–1.48)
(0.68–1.44)
(0.19–0.93)
(0.53–4.48)
(2.33–3.56)
a: Including all selected variables in the regression model.
that one- fourth of all respondents believed anti-depressants would
harm a depressed and suicidal person.28 This group was less
educated, had less experience with depression and underestimated
both the seriousness of depression and the need for intervention.
Taken together, these findings pinpoint the necessity of discussing
patients’ beliefs about treatment and disease when initiating
anti-depressant treatment.
The present study determined that early discontinuation was
more common among individuals who received social assistance.
We detected no excess risk for unemployed individuals, for those
with an income <60% of the median income or for those who
received student allowances in the preceding year. While some
previous studies reported no differences by income level, others
did.12,14 Milea et al.29 reported higher levels of early discontinuation
among individuals enrolled in Medicaid, which can indicate low
income.29 In general, income levels are lower and income differences
are less pronounced in young adulthood compared with older age
groups, possibly explaining the absence of differences by income in
our study.
On average, our study population used two co-medications.
Earlier studies reported slightly higher numbers but they also
included older age groups.4,9 Excluding women’s use of oral contraceptives, the largest groups of concurrently used drugs were antibiotics, sedatives and hypnotics. Concurrent use of sedatives and
hypnotics in our study agreed with data from studies of
anti-depressant users in mixed adult age groups, which are
generally older.4,5,9 Concurrent use of sedatives and hypnotics was
less common in early discontinuers, possibly indicating fewer
contacts with health services or less severity. To avoid sleep disturbances and anxiety, healthcare providers commonly add a sedative or
hypnotic when initiating SSRI treatment, possibly explaining why
early discontinuation occurred less commonly among patients with
concurrent use of these drugs. However, concurrent use as a proxy
for severity is very unspecific.
We observed disparities between our study population and the
reference population. Women and socially vulnerable groups, i.e., individuals with lower education and those needing financial support
were overrepresented among anti-depressant users, indicating the
importance of including socio-economic factors when studying
anti-depressant use.
Our findings regarding early discontinuation and factors
associated with early discontinuation were similar to previous
438
European Journal of Public Health
Table 4 Characteristics of new anti-depressant users, i.e. study population (n = 25 003), and reference population (n = 500 000)
Characteristic
Sex
Male
Female
Age (years)
20–24
25–29
30–34
Marital status
Unmarried
Married
Divorced or widow/widower
Number of people in the household
1
2
3–5
6 or more
Background
Born in Sweden, two parents born in Sweden
Born in Sweden, one parent born in Sweden
Born outside Sweden, at least one parent born in Sweden
Born in Sweden, two parents born outside Sweden
Born outside Sweden, two parents born outside Sweden
Country of birth
Sweden
Western industrial countries
Eastern Europe
Other
Highest attained education
Mandatory education (0–10 years)
Upper secondary school
Higher education <2 years
Higher education 2 years
Activity on labour market
Employed
Student
Received social assistance
Unemployed
Socio-economic status
Upper white-collar
Lower white-collar
Blue-collar
Other
Income
Disposable income <60% of the median value
Annual disposable income [hundreds of EUR (SEK 1= EUR 0.1)]
Median (IR)
Annual disposable household income (hundreds of EUR)
Median (IR)
Study population
Reference population
n
Rate per 1000
n
Rate per 1000
9298
15 701
372
628
259 264
240 736
519
481
<0.0001
6519
8310
10 174
261
332
407
162 153
160 972
176 875
324
322
354
<0.0001
19 262
4308
1210
777
174
49
392 554
91 631
10 062
794
185
20
<0.0001
12 356
2943
9065
403
499
119
366
16
238 374
48 284
203 466
9436
477
97
408
19
<0.0001
17285
2401
88
1225
1112
782
109
4
55
50
355 793
37 701
4384
20 077
20 379
812
86
10
46
47
<0.0001
21 085
894
966
2013
845
36
39
81
420 489
23 126
16 836
32 050
841
46
34
64
<0.0001
5064
11 910
1969
5415
208
489
81
222
44 583
247 430
43 517
143 440
93
517
91
300
<0.0001
11 851
6510
4635
4450
479
263
187
180
276 986
142 768
37 659
75 191
554
286
75
150
<0.0001
<0.0001
<0.0001
<0.0001
4271
6432
6951
180
239
361
390
10
109 045
98 146
162 221
5670
291
262
433
15
<0.0001
5725
229
125 226
251
<0.0001
121.8
78.4
128.1
99.5
177.4
197.6
213.7
229.3
P-value
Percentages per category were calculated excluding missing values. Pearson’s chi-square test was used to analyse differences between the
study population and the reference population.
studies.4,5,12,13 Our findings regarding early discontinuation likely
can be generalized to other settings with similar safety nets for
health care and medication costs. These safety nets are an
important aspect that substantially impact access to health care
and medicines.
Strengths and limitations
Our study presents data from a national database that encompasses
all filled prescriptions in Sweden, independent of reimbursement
status. Our data does not include drugs used for in-patient
hospital care, and we did not gather any data on hospitalizations.
Since depression and anxiety are largely treated in ambulatory care,
the majority of patients likely are included in the database. Since
some individuals classified in our study as early discontinuers may
have been hospitalized after they filled their first prescription, they
possibly were misclassified. However, since such individuals
probably would need new prescription medicines following
discharge and thus would need to fill a second prescription, it is
unlikely that hospitalization within the first 6 months altered our
results. Importantly, only 4% of all psychiatric inpatient hospitalizations in Sweden had a length of 85 days.30 Since earlier studies
reported higher persistence among individuals who received their
first anti-depressant prescription from a psychiatrist rather than a
GP, we tried to describe the treatment setting that issued the index
prescription.9 However, register data on treatment setting is scarce,
the sphere of activity was missing on some dispensed prescriptions
and the register does not include information on prescribers’
specialty.
Some individuals in our study group lacked socio-economic information. Indeed, the most common variable recorded as unknown
or missing was parental country of birth. The procedure for
Socio-economic determinants of anti-depressant discontinuation
recording such data has varied over time and uncertainties can exist
for migrating adolescents or adults who arrive in Sweden independently. While this lack reduced the numbers included in the multiple
regression models, it likely did not result in overestimated effects.
Information about indication was not available in a format
that allowed statistical processing, a significant but common
limitation in register-based research. Consequently, we did not
know whether an anti-depressant was intended for treatment of
depression or another indication. However, prescriptions for
anti-depressant treatment of both depression and anxiety disorders
should last at least six months. We also lacked information about
diagnosis or severity, an important factor in assessing whether individuals with a more severe illness also discontinued treatment
earlier.
2
Sihvo S, Isometsa E, Kiviruusu O, et al. Antidepressant utilisation patterns and
determinants of short-term and non-psychiatric use in the Finnish general adult
population. J Affect Disord 2008;110:94–105.
3
The Swedish Council on Technology Assessment in Health Care. Behandling av
depressionssjukdomar. En systematisk litteraturöversikt Treatment of depression.
Stockholm; 2004.
4
van Geffen EC, Gardarsdottir H, van Hulten R, et al. Initiation of antidepressant
therapy: do patients follow the GP’s prescription? Br J Gen Pract 2009;59:81–7.
5
van Geffen EC, van Hulten R, Bouvy ML, et al. Characteristics and reasons
associated with nonacceptance of selective serotonin-reuptake inhibitor treatment.
Ann Pharmacother 2008;42:218–25.
6
Rosholm JU, Andersen M, Gram LF. Are there differences in the use of selective
serotonin reuptake inhibitors and tricyclic antidepressants?. A prescription database
study. Eur J Clin Pharmacol 2001;56:923–9.
7
Rosholm JU, Gram LF, Isacsson G, et al. Changes in the pattern of antidepressant
use upon the introduction of the new antidepressants: a prescription database study.
Eur J Clin Pharmacol 1997;52:205–9.
8
Gardarsdottir H, Egberts AC, van Dijk L, et al. An algorithm to identify
antidepressant users with a diagnosis of depression from prescription data.
Pharmacoepidemiol Drug Saf 2009;18:7–15.
9
Gardarsdottir H, van Geffen EC, Stolker JJ, et al. Does the length of the first antidepressant treatment episode influence risk and time to a second episode? J Clin
Psychopharmacol 2009;29:69–72.
Conclusion
We show here that more than one fourth of new anti-depressant
users discontinue anti-depressant treatment after filling a prescription only once, suggesting suboptimal use in relation to therapeutic
guidelines. Early discontinuation occurred more commonly among
individuals born outside Sweden with non-Swedish parents and
among individuals who received financial support from social
services. Taken together with previous studies reporting that early
discontinuers tend not to inform their physician, our data indicate
that these groups might need greater monitoring during the
initiation of anti-depressant treatment. Combined with systematic
follow up regarding adherence and treatment experience, prescriber
awareness of characteristics associated with increased risk for early
discontinuation of anti-depressant treatment, can improve
treatment outcomes.
Acknowledgement
The authors are grateful to Ms. Karen Williams, KWills Editing
Services, for help with language editing the manuscript.
Funding
Data collection for this study as supported in part by a post-doctoral
scholarship from the Swedish Lundbeck foundation. The study was
also financed with internal funds.
Conflicts of interest: None declared.
Key points
Among new anti-depressant users aged 20–34 years, more
than one fourth discontinued anti-depressant use early.
Early discontinuation occurred more commonly among individuals born to non-Swedish parents and among those
who received social assistance, but less commonly among
women and among individuals with at least two years of
higher education.
Individuals with foreign background, both first and second
generation migrants, and recipients of social assistance
might require greater support during initiation of
anti-depressant therapy to facilitate initiation and maintenance of a sufficiently long treatment period.
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European Journal of Public Health, Vol. 23, No. 3, 440–446
ß The Author 2012. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.
doi:10.1093/eurpub/cks088 Advance Access published on 18 July 2012
.........................................................................................................
Cross national study of leisure-time physical activity in
Dutch and English populations with ethnic group
comparisons
Jeroen S. L. de Munter1, Charles Agyemang1, Irene G. M. van Valkengoed1, Raj Bhopal2,
Paola Zaninotto3, James Nazroo4, Anton E. Kunst1, Karien Stronks1
1
2
3
4
Department of Public Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
Public Health Sciences Section, Centre for Population Health Sciences, University of Edinburgh, Edinburgh, UK
Department of Epidemiology and Public Health, UCL, London, UK
Department of Sociology, School of Social Sciences, University of Manchester, Manchester, UK
Correspondence: Jeroen SL de Munter, Meibergdreef 9, P.O. 22660, 1100 DD, Amsterdam, The Netherlands,
tel: 0031 20 566 8462, fax: 0031 020 697 2316, e-mail: [email protected]
Background: Variations between countries in leisure-time physical activity (LTPA) can be used to test the convergence thesis, which expects that ethnic minority groups change towards the LTPA levels of the native population
of host countries. The aim of this study was to test whether similar differences in LTPA between the native
populations of England and the Netherlands are also observed among the Indian and African descent groups
living in these countries. Methods: We used English and Dutch population-based health surveys that included
participants aged 35–60 years of European (nenglish = 14 723, ndutch = 567), Indian (nenglish = 1264, ndutch = 370) and
African-Caribbean (nenglish = 1112, ndutch = 689) descent. Levels of LTPA (30-minute walking, any reported cycling,
gardening, dancing and playing sports) were estimated with age-sex-standardized prevalence rates. Comparisons
among groups were made using adjusted Prevalence Ratios (PRs). Results: Within both countries and compared
with the European group, Indian and African groups had lower levels of gardening and cycling, whereas the
African groups had higher levels of dancing. Between countries, among the European groups, the Netherlands
showed higher prevalence of cycling than England, PR = 2.26 (95% CI: 2.06–2.48), and this was 2.85 (1.94–4.19)
among Indian descent, and 2.77 (2.05–3.73) among African descent. For playing sports, this was PR = 1.30
(1.23–1.38), 1.43 (1.24–1.66) and 1.22 (1.10-1.34), whereas for gardening this was PR = 0.71 (0.65–0.78), 0.65
(0.52–0.81) and 0.75 (0.62–0.90), respectively. Walking and dancing showed inconsistent differences between
the countries and ethnic groups. Conclusion: This cross-national comparison supports the expectation that LTPA
of Indian and African descent groups converge towards the national levels of England and the Netherlands
respectively.
.........................................................................................................
Introduction
arge differences are observed in physical activity of people
1,2
For instance, higher levels of recommended
physical activity are observed in the Netherlands than Sweden and
Great Britain.1 These differences between countries have also been
identified regarding specific activities. For example, walking seems
more prevalent in Great Britain than in the Netherlands, and Dutch
people cycle more than the British.
The variation in levels of physical activity between countries can
be used to test the convergence hypothesis, i.e. that ethnic minority
groups change their behaviour towards the general population.
Lbetween countries.
However, studies within country do not always observe convergence
towards the general population.3–6 In a cross-national comparison,
this would mean that the differences in leisure-time physical activity
(LTPA) between countries would be observed similarly in ethnic
minority groups with a reasonable duration of residence, which is
a novel way of studying convergence.
In this study, we assessed the convergence hypothesis for LTPA in
Dutch and English ethnic minority groups and the European descent
populations. More specifically, we assessed whether differences
between England and the Netherlands in current levels of walking,
cycling, gardening, dancing and playing sports are also observed
among the Indian and African descent groups living in these