Table 17, Input parameters utilised in the economic model of pharmacological treatments for people with GAD - Common Mental Health Disorders

Input parameter	Deterministic value	Source of data – comments
Sensitivity of identification methods:
GAD-2 (cut off ≥3)	0.86	KROENKE2007
GAD-7 (cut off ≥8)	0.92	KROENKE2007
GP assessment	0.34	Wittchen and colleagues (2002); Davidson and colleagues (2010)
Specificity of identification methods:
GAD-2 (cut off ≥3)	0.83	KROENKE2007
GAD-7 (cut off ≥8)	0.76	KROENKE2007
GP assessment	0.9	GDG assumption

Probability of treatment response:
Active monitoring	1.00	GDG estimate – see text for more details
Low-intensity interventions	0.635	Titov and colleagues (2009) – CCBT (low-intensity intervention) for people with GAD NCCMH (2011a) – guideline meta-analysis
High-intensity intervention	0.40	NCCMH (2011a) – network meta-analysis of data included in the guideline systematic review of pharmacological treatments
Drug therapy with sertraline	0.63

Utilities:
Response	0.760	Allgulander and colleagues (2007)
Non-response	0.630	Allgulander and colleagues (2007)
No relapse following response (remission)	0.790	Allgulander and colleagues (2007)

Identification costs:
GAD-2	£30	Based on 10 minutes of surgery/clinic GP consultation for administration of the GAD-2, 15 minutes for administration of the GAD-7 and one visit for GP assessment (GDG expert opinion); combined with national unit costs (Curtis, 2009)
GAD-7	£45
GP assessment	£35

Cost of low-intensity psychological interventions:
Non-facilitated self-help	£15	NCCMH (2011a) – non-facilitated self-help estimated to consist of one 15-minute session with a mental health nurse (band 5) plus the use of a booklet costing £4; guided self-help estimated to comprise three to six sessions with a mental health nurse (band 5), with the first session lasting 45 minutes and the rest 30 minutes, plus the use of a booklet costing £4; psychoeducational group estimated to consist of six sessions of 2 hours each, provided by two mental health nurses (band 5) to groups of ten to 30 people. Unit cost of mental health nurse (band 5) £44 per hour of face-to-face contact (Curtis, 2009)
Guided self-help	£117
Psychoeducational group	£72
Mean cost:	£68

Cost of high-intensity psychological interventions:
CBT or applied relaxation (12 sessions)	£900	NCCMH (2011a) – each session lasting 1 hour, provided by clinical psychologists. Unit cost of clinical psychologist: £75 per hour of client contact (Curtis, 2009)
Three booster sessions for responders only	£225

Cost of pharmacological treatment:
Acute phase (8 weeks)	£108.18	NCCMH (2011a) – based on use of sertraline at a daily dosage of 100 mg and GP monitoring visits, comprising one visit at initiation of treatment, two more visits over the first 8 weeks of treatment and another visit during maintenance treatment. Cost of sertraline based on BNF 59 (British Medical Association & the Royal Pharmaceutical Society of Great Britain, March 2010); cost of GP visit based on national sources (Curtis, 2009)
Maintenance treatment (26 weeks)	£45.34

Weekly health and social care cost incurred by people with GAD	£15.47	NCCMH (2011a) – weekly cost incurred by people with GAD (true positive) not responding to treatment and by people with GAD who failed to be diagnosed (false negative). Estimate based on resource use data reported in the most recent adult psychiatric morbidity survey in England (McManus et at., 2009), further expert opinion and national unit costs (Curtis, 2009)

Input parameter

Deterministic value

Source of data – comments

Sensitivity of identification methods:

GAD-2 (cut off ≥3)

0.86

KROENKE2007

GAD-7 (cut off ≥8)

0.92

KROENKE2007

GP assessment

0.34

Wittchen and colleagues (2002); Davidson and colleagues (2010)

Specificity of identification methods:

GAD-2 (cut off ≥3)

0.83

KROENKE2007

GAD-7 (cut off ≥8)

0.76

KROENKE2007

GP assessment

0.9

GDG assumption

Probability of treatment response:

Active monitoring

1.00

GDG estimate – see text for more details

Low-intensity interventions

0.635

Titov and colleagues (2009) – CCBT (low-intensity intervention) for people with GAD
NCCMH (2011a) – guideline meta-analysis

High-intensity intervention

0.40

NCCMH (2011a) – network meta-analysis of data included in the guideline systematic review of pharmacological treatments

Drug therapy with sertraline

0.63

Utilities:

Response

0.760

Allgulander and colleagues (2007)

Non-response

0.630

Allgulander and colleagues (2007)

No relapse following response (remission)

0.790

Allgulander and colleagues (2007)

Identification costs:

GAD-2

£30

Based on 10 minutes of surgery/clinic GP consultation for administration of the GAD-2, 15 minutes for administration of the GAD-7 and one visit for GP assessment (GDG expert opinion); combined with national unit costs (Curtis, 2009)

GAD-7

£45

GP assessment

£35

Cost of low-intensity psychological interventions:

Non-facilitated self-help

£15

NCCMH (2011a) – non-facilitated self-help estimated to consist of one 15-minute session with a mental health nurse (band 5) plus the use of a booklet costing £4; guided self-help estimated to comprise three to six sessions with a mental health nurse (band 5), with the first session lasting 45 minutes and the rest 30 minutes, plus the use of a booklet costing £4; psychoeducational group estimated to consist of six sessions of 2 hours each, provided by two mental health nurses (band 5) to groups of ten to 30 people. Unit cost of mental health nurse (band 5) £44 per hour of face-to-face contact (Curtis, 2009)

Guided self-help

£117

Psychoeducational group

£72

Mean cost:

£68

Cost of high-intensity psychological interventions:

CBT or applied relaxation (12 sessions)

£900

NCCMH (2011a) – each session lasting 1 hour, provided by clinical psychologists. Unit cost of clinical psychologist: £75 per hour of client contact (Curtis, 2009)

Three booster sessions for responders only

£225

Cost of pharmacological treatment:

Acute phase (8 weeks)

£108.18

NCCMH (2011a) – based on use of sertraline at a daily dosage of 100 mg and GP monitoring visits, comprising one visit at initiation of treatment, two more visits over the first 8 weeks of treatment and another visit during maintenance treatment. Cost of sertraline based on BNF 59 (British Medical Association & the Royal Pharmaceutical Society of Great Britain, March 2010); cost of GP visit based on national sources (Curtis, 2009)

Maintenance treatment (26 weeks)

£45.34

Weekly health and social care cost incurred by people with GAD

£15.47

NCCMH (2011a) – weekly cost incurred by people with GAD (true positive) not responding to treatment and by people with GAD who failed to be diagnosed (false negative). Estimate based on resource use data reported in the most recent adult psychiatric morbidity survey in England (McManus et at., 2009), further expert opinion and national unit costs (Curtis, 2009)

From: 5, CASE IDENTIFICATION AND FORMAL ASSESSMENT

Common Mental Health Disorders: Identification and Pathways to Care.

NICE Clinical Guidelines, No. 123.

National Collaborating Centre for Mental Health (UK).

Leicester (UK): British Psychological Society (UK); 2011.

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Table 17Input parameters utilised in the economic model of pharmacological treatments for people with GAD