Cost-effectiveness modeling for neuropathic pain treatments: investigating the relative importance of parameters using an open-source model

Figures & data

Figure 1. Diagram of cost-effectiveness model structure⁶. Abbreviation. AEs, adverse effects.

Table 1. Model parameters.

Parameter	Mean (SE)	Distribution	Source
Pregabalin probabilities (with no dose adjustment
<30% reduction in pain	0.43 (0.079)	Dirichlet	NICE^6
30–49% reduction in pain	0.16 (0.0077)
≥50% reduction in pain	0.41 (0.082)
Withdrawal due to AEs	0.19 (0.033)	Beta
Dizziness	0.36 (0.069)
Nausea	0.12 (0.046)
Utilities
<30% reduction in pain	0.16 (0.036)	Beta	NICE^6, McDermott et al.^7, IASP^22
30–49% reduction in pain	0.46 (0.015)	Beta
≥50% reduction in pain	0.67 (0.015)	Beta
Withdrawal due to AEs (multiplier)	0.86 (0.037)	Uniform (0.8–0.93)	NICE^6, Wilby et al.^23
Dizziness (absolute utility decrement)	0.12 (0.0024)	Beta	NICE^6, Revicki and Wood^24
Nausea (absolute utility decrement)	0.065 (0.0013)	Beta	NICE^6, Sullivan et al.^25
Costs
Pregabalin (20-week cost)	£325.59 (daily rate = £2.33)	–	NICE^6, NHS^20
Cyclizine hydrochloride (50 mg t.i.d)^a	£0.4407	–
GP visit (lasting 17.2 min)	£63.70	–	NICE^6, PSSRU^19
Resource use
Treatment of minor AEs (dizziness/nausea) with antiemetic  medication (cyclizine hydrochloride) - duration (days)	10.5 (2.02)	Uniform (7–14)	NICE^6
No. GP visits for minor AEs (dizziness/nausea)	3 (0.578)	Uniform (1–2)
No. GP visits for withdrawal AEs (dizziness/nausea)	3 (0.41)	Uniform (2–4)

Standard error values were derived from the 95% intervals provided in the report.

^aCyclizine hydrochloride is an add-on treatment to manage the side-effects that are commonly associated with pregabalin treatment (e.g. nausea and vomiting).

The beta distribution applies to a variable that must take values in the range 0–1 (e.g. probabilities), parameterized by two positive shape parameters.

The Dirichlet distribution is the multivariate generalization of the beta distribution that applies to a vector of quantities constrained between 0–1.

Abbreviations. AEs, adverse effects; GP, general practitioner; t.i.d, ter in die.

Table 2. Model scenario analyses results.

Scenarios	Scale Factor		Pregabalin		Hypothetical treatment		NMB (£)
	Efficacy (Pain Relief)	Adverse Effects	Costs	QALYs	Costs	QALYs
1	0.9	0.6	358.72	0.143	345.47	0.141	–26.75
2	1.0	0.8	358.72	0.143	352.09	0.146	66.63
3	1.1	1.0	358.72	0.143	358.72	0.151	160.00
4	1.2	1.2	358.72	0.143	365.35	0.155	233.37
5	1.3	1.4	358.72	0.143	371.97	0.159	306.75

Abbreviations. NMB, Net Monetary Benefit; QALYs, Quality Adjusted Life Years.

Figure 2. Net monetary benefit of the hypothetical treatment relative to pregabalin. Abbreviation. GBP, Great British Pounds.

National Institute for Health and Care Excellence (NICE). Clinical guideline [CG173] - Neuropathic pain in adults: pharmacological management in non-specialist settings. United Kingdom: NICE; 2017

 Google Scholar

McDermott AM, Toelle TR, Rowbotham DJ, et al. The burden of neuropathic pain: results from a cross-sectional survey. Eur J Pain 2006;10:127

 PubMed Web of Science ®Google Scholar

International Association for the Study of Pain. What is neuropathic pain? United States: IASP; 2014

 Google Scholar

Wilby J, Kainth A, Hawkins N, et al. Clinical effectiveness, tolerability and cost-effectiveness of newer drugs for epilepsy in adults: a systematic review and economic evaluation. Health Technol Assess 2005;9:1-157, iii–iv

 PubMed Web of Science ®Google Scholar

Revicki DA, Wood M. Patient-assigned health state utilities for depression-related outcomes: differences by depression severity and antidepressant medications. J Affect Disord 1998;48:25-36

 PubMed Web of Science ®Google Scholar

Sullivan SD, Lew DP, Devine EB, et al. Health state preference assessment in diabetic peripheral neuropathy. Pharmacoeconomics 2002;20:1079-89

 PubMed Web of Science ®Google Scholar

National Health Service (NHS). Electronic Drug Tariff. United Kingdom: NHS; 2013

 Google Scholar

Personal Social Services Research Unit (PSSRU). Unit costs of health and social care. United Kingdom: PSSRU; 2012

 Google Scholar

Data availability statement

The data that support the findings of this study are openly available in Zenodo at doi.org/10.5281/zenodo.1212328.