Use of Antidepressants Before and After Road Transport Injury

J. Berecki-Gisolf, A. Collie, B. Hassani Mahmooei, R. McClure

Australasian Compensation Health Research Forum

19th November 2015

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Background and study aim

Road traffic injury can have an impact on mental health

Mental health consequences of injury contribute substantially to the burden of road traffic injury

Among trauma patients, pre-existing mental disorders are more prevalent than in the general population

The aim of this study was to describe antidepressant use before and after road traffic injury, in order to examine the assumption

that post injury antidepressant use can be attributed to the

incident injury

Antidepressant prescription use was considered a proxy for prevalence of treated mental health conditions

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Medicare and PBS data linkage study

Transport Accident Commission (TAC)

Non-catastrophic injury that occurred between 2010-2012

Informed consent for Medicare & PBS data linkage (8%)

MBS/PBS data provided by the Department of Human Services

Linked to TAC claims and payment records: Compensation Research Database (CRD), ISCRR

De-identified research database

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Sample & Data

734 Study participants: 335 men, 399 women.

42,629 Medicare items &

27,755 PBS items used 12 months pre- to 18 months post-injury

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Antidepressant use: Method

Antidepressants used in the 12 months prior to crash were identified in the PBS data

Antidepressants used in the 12 months following the crash were identified in the PBS data and the TAC payment records

ATC codes were added to the PBS item codes: Antidepressants were identified as starting with N06A.

TAC payments for non-PBS prescriptions were processed manually

Use was expressed as number of antidepressant users as well as defined daily dosages (DDD) per 1000 person-days

It was assumed that filled prescriptions were consumed

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Antidepressant use: Findings

12% of study participants used antidepressants in the year before injury

Pre-injury use was 84 DDD / 1000 person-days in the sample

17% used antidepressants in the year after injury

Post-injury use was 114 DDD / 1000 person-days

Pre-injury, non-selective monoamine reuptake inhibitors (NSMRI) accounted for 7%, selective serotonin reuptake inhibitors (SSRI) for

50% and other antidepressants for 43% of use

Post-injury, NSMRI use increased by 22%, SSRI use increased by 5% and other antidepressant use increased by 42%

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Substance name Subgroup DDD/1000 p.d. DDD/1000 p.d.

Imipramine

Non-selective monoamine reuptake inhibitors

0.00 0.04

Amitriptyline 3.89 5.76

Nortriptyline 0.06 0.10

Doxepin 0.37 0.33

Dosulepin 1.63 1.35

Fluoxtine

Selective serotonin reuptake inhibitors

6.58 4.81

Citalopram 3.76 3.55

Paroxetine 3.92 2.80

Sertraline 10.30 16.46

Fluvoxamine 1.85 0.39

Escitalopram 15.89 16.30

Mirtazapine

Other antidepressants

6.33 11.81

Venlafaxine 16.97 22.34

Duloxetine 8.83 15.42

Desvenlafaxine 3.97 12.65

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Distribution of first script

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Distribution of last script

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Pre and post injury use

Pre-injury Post-injury

N Row % DDD/1000

p.d.

Row

%

DDD/1000

p.d.

All 734 12 84.4 17 114.1

Sex

Men 335 8 54.6(1) 15 90.6(2)

Women 399 17 109.4 20 133.9

Age

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Pre and post injury use

Pre-injury Post-injury

N Row

%

DDD/1000

p.d.

Row

%

DDD/1000

p.d.

Role in the accident

Car-driver 394 16 109.3(1) 20 143.5(2)

Car-passenger 59 14 69.4 19 91.7

Motor cyclist 93 2 16.9 12 66.6

Pedestrian 83 16 107.8 23 139.5

Cyclist 94 3 18.3 4 11.1

Other 11 18 228.6 27 272.7

(1) P=0.0006; (2) P=0.002

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Pre and post injury use

Pre-injury Post-injury

N Row % DDD/1000p.d. Row % DDD/1000p.d.

Injury type

Musculoskeletal 200 17 116.1 21 127.8

Orthopaedic 179 11 63.4 18 93.7

Other Injury 223 11 85.5 12 112.6

Other severe 132 11 62.8 20 123.6

Whiplash injury

Yes 179 17 119.3(1) 21 130.0

No 555 11 73.1 16 109.0

(1) P=0.03

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New onset post-injury use

There were 128 study participants who used antidepressants in the year after injury. Among these participants, in the pre-injury year:

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Conclusions

Among those taking antidepressant medication in the year after injury, this could be considered to be a consequence of the injury in only 45%

of cases

For the remaining 55% it was a continuation of pre-injury antidepressant use

Pre-injury antidepressant use was particularly prevalent amongst women and among those with whiplash injury

Antidepressant use was rare among injured cyclists

These results highlight the importance of obtaining information on pre-injury health status before interpreting post-injury health service use to

be an outcome of injury

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The study was funded by the

Transport Accident Commission

(TAC) and the Victorian Workcover

Authority (VWA) Institute for Safety,

Compensation and Recovery

Research (ISCRR)