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Table 1 Summary of model inputs: baseline characteristics and treatment effects

From: Cost-effectiveness of dapagliflozin versus DPP-4 inhibitors as an add-on to Metformin in the Treatment of Type 2 Diabetes Mellitus from a UK Healthcare System Perspective

Baseline characteristic Baseline value
Age (years) 57.51
Proportion female (%) 47.00
Duration of diabetes (years) 6.01
Height (m) 1.69
Proportion Afro-Caribbean (%) 6.20b
Proportion smokers 36.90
HbA1ca (%) 8.05
Weight (kg) 87.84
SBP (mmHg) 133.30
TC (mg/dL) 199.57
HDL-C (mg/dL) 44.09
Treatment effect DAPA + MET DPP-4i + MET Insulin + METg Intensified insulinc
∆HbA1cc (%) −0.69 −0.61 −1.10 −1.11
∆Weightc (kg) −3.36 −0.61 +1.08 +1.90h
∆SBPc (mmHG) 0d 0d 0d 0d
∆TCc (mg/dL) 0d 0d 0d 0d
∆HDL-Cc (mg/dL) 0d 0d 0d 0d
Probability of Discontinuatione 0.081 0.043 0d 0d
Probability. of hypoglycaemic events (symptomatic)f 0.031 0.046 0.011 0.616
Probability of hypoglycaemia (severe)f 0.0004 0.001 0.037 0.022
Probability of urinary tract infectionf 0.074 0.054 0d 0d
Probability of genital infectionf 0.123 0d 0d 0d
Event Utility decrement Source
Diabetes-related complications   
Ischaemic heart disease 0.090 Clarke, 2003 [23]
Myocardial infarction 0.550 Clarke, 2003 [23]
Congestive heart failure 0.108 Clarke, 2003 [23]
Stroke 0.164 Clarke, 2003 [23]
Amputation 0.280 Clarke, 2003 [23]
Blindness 0.074 Clarke, 2003 [23]
End-stage renal disease 0.263 Currie, 2005 [24]
Hypoglycaemia   
Symptomatic 0.042 Currie, 2006 [39]
Nocturnal 0.008 Currie, 2006 [39]
Severe 0.047 Currie, 2006 [39]
Adverse events   
Urinary tract infection (UTI) 0.00283 Barry, 1997 [25]
Genital infection 0.00283 Assumed to be the same as UTI
BMI changes   
Per unit increase 0.0472 Lane, 2012 [26]
Per unit decrease +0.0171 Lane, 2012 [26]
Drug acquisition cost Price per tableti Dose per tablet/pen Daily dose Annual cost (£)
Dapagliflozin £1.31 10 mg 10 mg £476.92
DPP-4i (sitagliptinj) £1.19 100 mg 100 mg £433.57
Metformin £0.02 500 mg 2000 mg £23.46
Insulink (Insuman® Basal) £0.47/day 300 IU 40 IU £170.23
Intensified insulin £0.70/day 300 IU 60 IU £256.96
Diabetes-related complication costl Fatal Non-Fatal Maintenance Source
Ischaemic heart disease - £3,479 £1,149 Clarke, 2003 [21]
Myocardial infarction £2,244 £6,709 £1,105 Clarke, 2003 [21]
Congestive heart failure £3,880 £3,880 £1,360 Clarke, 2003 [21]
Stroke £5,658 £4,103 £776 Clarke, 2003 [21]
Amputation £13,359 £13,359 £771 Clarke, 2003 [21]
Blindness - £1,752 £742 Clarke, 2003 [21]
End-stage renal disease - £34,806 £34,806 Baboolal, 2008 [40]
Adverse event, renal monitoring and discontinuation costs Cost input Source
Severe hypoglycaemic event £390 Hammer, 2009 [41]
Renal monitoring £38.67 Assumed to incur one GP visit cost and a 24-hour creatine clearance determination [42, 43]
Urinary tract infection, genital infection £36 Assumed to incur one GP visit cost [42]
Discontinuation £36 Assumed to incur one GP visit cost [42]
  1. aValue was applied as the HbA1c switching threshold; it was considered to be a representative threshold value in real-world UK clinical practice as it was the average baseline HbA1c value of patients entering the phase 3 clinical trials that were included in the indirect comparison before switching to dual oral therapy
  2. bValue sourced from randomised controlled trial by Nauck et al., 2010 [19]
  3. ∆ Mean change from baseline
  4. c Effects apply to the first year after treatment initiation
  5. d No estimate available and/or zero value assumed
  6. eProbability of discontinuation was applied during the first model cycle
  7. fProbabilities of adverse events were applied during every model cycle
  8. gMonami, 2008 [44]
  9. ‡‡NICE HTA report Chapter 4 [45]
  10. hWeight change from Montanana, 2008 [46]. Chosen as most recent study reporting weight effect included in the NICE HTA report
  11. iThe daily costs are based on pack costs and have been rounded. The source of the unit costs are England and Wales Drug Tariff costs, February 2012. These costs are in general consistent with BNF63 drug prices
  12. jSitagliptin is the most frequently prescribed DPP-4i in the UK (80 % of DPP-4i market as of December 2011, data on file)
  13. kThe cost of insulin was based on a patient baseline weight of 88 kg, which if it remained stable would equate to an annual cost of £170.23 (and £256.96 for intensified insulin). However, in the model, weight changed over time, hence the actual annual cost of insulin (with dosage according to weight) in the economic analysis varies according to the simulated change in weight. Insulin daily cost per kg = £0.0053, insulin intensified daily cost per kg = £0.008
  14. lPrices were indexed to 2011 using the Hospital and Community Health Services Pay & Prices index
  15. Abbreviations: HbA1c, Glycated haemoglobin; SBP, systolic blood pressure; TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; ∆, absolute change from baseline; GP, general practitioner