Cost-consequence analysis of sitagliptin versus sulfonylureas as add-on therapy for the treatment of diabetic patients in Italy

Figures & data

Table 1 Parameters used to model clinical events, parameters’ value, and source of data

Parameter type	SITA	SU	Insulin	Source
Frequency of monthly glucose automonitoring	8.3a	50b	75c	SID – AMD national guidelines^Citation6
Yearly incidence of non-severe hypoglycemic events	7%	22%	8.6%	Arechavaleta et al (2011);^Citation13 Sreenan et al (2014)^Citation17
Yearly incidence of severe hypoglycemic events	0.19%	1.16%	11.8%	Arechavaleta et al (2011);^Citation13 Leese et al (2003)^Citation18
Yearly incidence of MACE	0.97%	1.86%	–	Monami et al (2013)^Citation14
Switch to insulin
6 months	14%	26%	–	Valensi et al (2015)^Citation11
12 months	24%	38%	–
18 months	31%	47%	–
24 months	36%	54%	–
30 months	41%	56%	–
36 months	44%	59%	–

Notes:

a The SID – AMD national guidelines indicated 25 over 3 months for DPP4-i.

b Minimum mean value per month among the three different ranges suggested for SU in the SID – AMD national guidelines: (25–50), (50–75), (75–100).

c Minimum value in the recommended range suggested for insulin in the SID – AMD national guidelines: (75–100). ‘–’ indicates not included in the analysis.

Abbreviations: DPP4-i, dipeptidyl peptidase 4 inhibitors; MACE, major cardiovascular events; SITA, sitagliptin; SU, sulfonylurea;

Table 2 Unit costs (Euros) associated with resource item and source of data

Resource Item	Unit cost	Details and source
Direct costs
Met	€0.06/die	Italian Medicines Agency^Citation19
SITA+Met	€1.24/die	Ex-factory daily net price
SU+Met	€0.21/die	Italian Medicines Agency,^Citation19 refer Table S1 for details
Insulin	€0.03/IU	Ex-factory daily net price
Strips	€0.506	Mean value over regional data
Needles	€0.116	Mean value over regional data
Outpatient visit	€20.66	Italian Ministry of Health 2013^Citation20
Severe hypoglycemia	€3,014	Nicolucci (2014)^Citation21
GP visit for non-severe hypoglycemia	€15.24	Mannocci et al (2009)^Citation22
MACE	€15,041	Literature + calculation as detailed in Table S2
Indirect costs
Cost/day	€100	€25,200 (GDP)/251 (working days per year), European statistics^Citation32
Cost/hour	€13	Cost per day/7.72^Citation32,Citation33
Severe hypoglycemia	€663	Calculation
Non-severe hypoglycemia	€124	Calculation

Abbreviations: GDP, gross domestic product; GP, general practitioner; MACE, major cardiovascular events; Met, metformin; SITA, sitagliptin; SU, sulfonylurea.

Table 3 Cost-consequence analysis SITA versus SU over 3-year time horizon (societal perspective)

Cost component	SITA+Met	SU+Met	Delta
Drug	€96,600,960	€13,212,990	€83,387,970
Distribution PHT	€16,807,081	€0	€16,807,081
Self-monitoring	€16,518,556	€80,368,536	−€63,849,980
Visits	€8,941,648	€7,221,703	€1,719,945
Hypos	€1,296,239	€6,255,716	−€4,959,477
MACE	€0	€23,501,390	−€23,501,390
Switch to insulin	€123,417,88	€184,868,478	−€61,450,592
Indirect costs	€2,154,480	€11,525,761	−€9,371,281
Total costs	€265,736,850	€326,954,574	−€61,217,723

Abbreviations: hypos, hypoglycemic events; MACE, major cardiovascular events; SITA, sitagliptin; SU, sulfonylurea; PHT, drugs included in the National Hospital-Territory Formulary.

Table 4 Cost-consequence analysis SITA versus SU over 3-year time horizon (INHS perspective)

Cost component	SITA+Met	SU+Met	Delta
Drug	€96,600,960	€13,212,990	€83,387,970
Distribution PHT	€16,807,081	€0	€16,807,081
Self-monitoring	€16,518,556	€80,368,536	−€63,849,980
Visits	€8,941,648	€7,221,703	€1,719,945
Hypos	€1,296,239	€6,255,716	−€4,959,477
MACE	€0	€23,501,390	−€23,501,390
Switch to insulin	€123,417,886	€184,868,478	−€61,450,592
Indirect costs	€0	€0	€0
Total costs	€263,582,370	€315,428,813	−€51,846,442

Abbreviations: hypos, hypoglycemic events; INHS, Italian National Health Service; MACE, major cardiovascular events; Met, metformin; SITA, sitagliptin; SU, sulfonylurea; PHT, drugs included in the National Hospital-Territory Formulary.

Figure 1 Avoided events SITA+Met versus SU+Met.

Abbreviations: hypo, hypoglycemic event; MACE, major cardiovascular events; Met, metformin; SITA, sitagliptin; SU, sulfonylurea.

Table 5 Scenario analysis: cost-consequence analysis SITA versus SU over 3-year time horizon (societal perspective) without MACE

Cost component	SITA+Met	SU+Met	Delta
Drug	€96,600,960	€13,212,990	€83,387,970
Distribution PHT	€16,807,081	€0	€16,807,081
Self-monitoring	€16,518,556	€80,368,536	−€63,849,980
Visits	€8,941,648	€7,221,703	€1,719,945
Hypos	€1,296,239	€6,255,716	−€4,959,477
MACE	€0	€0	€0
Switch to insulin	€123,417,886	€184,868,478	−€61,450,592
Indirect costs	€2,154,480	€11,525,761	−€9,371,281
Total costs	€265,736,850	€303,453,184	−€37,716,334

Abbreviations: hypos, hypoglycemic events; MACE, major cardiovascular events; Met, metformin; SITA, sitagliptin; SU, sulfonylurea; PHT, drugs included in the National Hospital-Territory Formulary.

Table 6 Scenario analysis: cost-consequence analysis SITA versus SU over 3-year time horizon (INHS perspective) without MACE

Cost voices	SITA+Met	SU+Met	Delta
Drug	€96,600,960	€13,212,990	€83,387,970
Distribution PHT	€16,807,081	€0	€16,807,081
Self-monitoring	€16,518,556	€80,368,536	−€63,849,980
Visits	€8,941,648	€7,221,703	€1,719,945
Hypos	€1,296,239	€6,255,716	−€4,959,477
Switch to insulin	€123,417,886	€184,868,478	−€61,450,592
Total costs	€263,582,370	€291,927,423	−€28,345,053

Abbreviations: hypos, hypoglycemic events; INHS, Italian National Health Service; MACE, major cardiovascular events; Met, metformin; SITA, sitagliptin; SU, sulfonylurea; PHT, drugs included in the National Hospital-Territory Formulary.

Figure 2 One-way sensitivity analysis: tornado graph.

Abbreviations: hypo, hypoglycemic event; MACE, major cardiovascular events; Met, Metformin; SITA, sitagliptin; SMBG, self-monitoring of blood glucose; SU, sulfonylurea.

Table S1 Details of data used to obtained average costs of drug costs for SU+Met

Drug	Dosage	Cpr per pack	Public price	Ex-factory price (per cpr)a	Daily cost	Daily cost SU+Metb
Gliclazide	Gliclazide 80 mg	40	€3.34	€0.0445	€0.08	€0.13
Gliclazide	Gliclazide 160 mg				€0.15	€0.21
Gliclazide	Gliclazide 240 mg				€0.23	€0.28
Gliclazide rp	Gliclazide 30 mg	60	€6.80	€0.0604	€0.10	€0.16
Gliclazide rp	Gliclazide 60 mg				€0.21	€0.26
Gliclazide rp	Gliclazide 120 mg				€0.41	€0.47
Glimepiride	Glimepiride 1 mg				€0.03	€0.09
Glimepiride	Glimepiride 2 mg	30	€2.12	€0.0377	€0.06	€0.12
Glimepiride	Glimepiride 3 mg	30	€3.56	€0.0633	€0.11	€0.16
Glimepiride	Glimepiride 4 mg	30	€3.56	€0.0633	€0.11	€0.16
Glimepiride	Glimepiride 5 mg				€0.17	€0.23
Glimepiride	Glimepiride 6 mg				€0.22	€0.27
Glibenclamide	Glibenclamide 5 mg	30	€2.94	€0.0523	€0.09	€0.14
Glibenclamide	Glibenclamide 10 mg				€0.18	€0.23
Average SU+Met price						€0.21

Notes:

a Prices from the Italian Medicines Agency.¹

b Including metformin daily cost of €0.06.

Abbreviations: cpr, compress; Met, Metformin; SITA, sitagliptin; SU, sulfonylurea.

Table S2 Details of data used to value direct costs of MACE

MACE	Costs (€)	Details and reference for costs	Weights	Reference
Revascularization	€27,519	Bypass coronarico con PTCA [coronary bypass with PTCA], DRG 106: Italian Ministry of Health 2013^Citation2	30%	Monesi (2005)^Citation3
MI	€9,704	€4,018 (acute phase, DRG 121–122) + €5,686 (1-year costs), DRG 106: Italian Ministry of Health (2013);^Citation2 Berto et al (2010).^Citation4	31%	Monesi (2005)^Citation3
Stroke	€10,063	€3,981 (acute phase, DRG 14) + €4,132 (first 3-months costs) + €680 (subsequent 3-months costs): Italian Ministry of Health (2013);^Citation2 Fattore et al (2012).^Citation5	35%	Monesi (2005)^Citation3
CV death	€4,348	Lucioni et al (2010)^Citation6	4%	Italian Hospital discharge data (2012)^Citation7
Average costs for MACE				€15,041

Abbreviations: CV, cardiovascular; DRG, diagnosis-related group; MACE, major cardiovascular events; MI, myocardial infarction; PTCA, percutaneous transluminal coronary angioplasty.

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