Laparoscopic adjustable gastric banding vs standard medical management in obese patients with type 2 diabetes: a budget impact analysis in the UK

Figures & data

Table 1.  Baseline characteristics of the simulated patient cohort.

Characteristic	Value	Reference
Mean start age (SD), years	46.9 (8.7)	Dixon et al.19
Mean duration of diabetes (SD), years	1.0 (0.33)*
Percentage male (%)	46.5
Mean HbA1c (SD), %	7.7 (1.4)
Mean SBP (SD), mmHg	135.9 (15.6)
Mean total cholesterol (SD), mg/dL	200.0 (56.7)
Mean HDL-cholesterol (SD), mg/dL	47.6 (11.1)
Mean body mass index (SD), kg/m^2	37.1 (2.7)

*Assumed, all patients in the Dixon et al.19 study had a duration of diabetes of less than 2 years.

HbA1c, glycated hemoglobin; HDL, high density lipoprotein cholesterol; SBP, systolic blood pressure; SD, standard deviation.

Table 2.  Treatment effects used in the modeling analysis.

Effect	LAGB	SMM	p-value	Reference
Change from baseline HbA1c (%)	−1.81 (1.24)	−0.38 (1.26)	<0.001	Dixon et al.19
Change from baseline SBP (mmHg)	−6.0 (17.9)	−1.7 (14.2)	0.37
Change from baseline total cholesterol (mg/dL)	3.6 (51.6)	−0.4 (31.4)	0.72
Change from baseline HDL (mg/dL)	12.6 (9.8)	2.6 (6.1)	<0.001
Change from baseline BMI (kg/m^2)*	−7.4 (0)	−0.35 (0)	<0.001

*Change in BMI was not reported. Mean baseline height was calculated from the baseline weight and BMI and used with the change in weight over the study duration to calculate the BMI at end-of-study (and hence the change in BMI).

BMI, body mass index; HbA1c, glycated hemoglobin; HDL, high density lipoprotein cholesterol; LAGB, LAP-BAND laparoscopic adjustable gastric banding system; SBP, systolic blood pressure; SMM, standard medical management.

Table 3.  Cost items captured in the bariatric surgery budget impact model.

Cost group	Cost items captured
LAGB	Single bariatric surgery healthcare resource group cost (code FZ05B)
Routine pre- and post-surgical consultations and treatment	GP visits, practice nurse visits, district nurse visits, outpatient clinic visits, community dietician visits, psychologist consultations, and very-low calorie diet products
Surgical complications	Band removal (in the case of adjustable gastric banding), revisional surgery, minor or major wound infection, deep vein thrombosis, pulmonary embolism, laparascopic cholecystectomy, and incisional hernia repair
Diagnostic tests	Complete blood counts, liver function tests, lipid profiles, and metabolic bone disease and nephrolithiasis testing
Asthma medication	Corticosteroids and long-acting beta-2 agonists
Sleep apnea treatment	Automatic positive airway pressure or continuous positive airway pressure devices and humidifier
Diabetes treatment	Insulin, metformin, sulfonylurea, glucagon-like peptide-1 (GLP-1) analogs, dipeptidyl peptidase-4 (DPP-4) inhibitor, and costs associated with self-monitoring of blood glucose
Concomitant medications	Anti-hypertensives, analgesics, anti-depressants, hypolipidemics, multivitamin supplements, vitamin D supplements, folic acid, and vitamin B12
Treatment of diabetes complications	Myocardial infarction, ischemic heart disease, congestive heart failure, stroke, end-stage renal disease, amputation, and blindness

LAGB, laparoscopic adjustable gastric banding.

Table 4.  Unit costs used in the base case analysis.

Cost item	Base case cost (GBP)	Reference
Myocardial infarction event	5091	Ray et al.21
Ischemic heart disease event	2641
Congestive heart failure event	2944
Stroke event	3114
End-stage renal disease onset	21,675
Blindness onset	1012
Amputation event	10,187
Myocardial infarction state	838
Ischemic heart disease state	872
Congestive heart failure state	1032
Stroke state	589
End-stage renal disease state	21,675
Blindness state	327
Amputation state	648
Metformin (per patient, per day)	0.17	Picot et al.24
Sulfonylurea (per patient, per day)	0.06
Insulin (per IU)	0.03	Department of Health26
SMBG test strip (per strip)	0.27
Anti-hypertensives (per patient, per day)	0.06	Picot et al.24
Analgesics (per patient, per day)	0.17
Anti-depressants (per patient, per day)	1.30
Hypolipidaemics (per patient, per day)	0.54
Multivitamins (per patient, per year)	0.00
Calcium citrate and vitamin D (per patient, per year)	14.44
Folic acid (per patient, per year)	7.93
Vitamin B12 (per patient, per year)	45.58
Cost of APAP machine	458.90	McDaid et al.27
Cost of CPAP machine	313.39
Cost of humidifier	167.89
Bariatric surgery HRG cost, major stomach or duodenum procedure without complications (HRG code FZ05B)	2540	NHS22
Abdominoplasty cost per procedure	2735
Band adjustment	897
Dietitian consultation (per visit)	43	NHS31
Community dietitian contact (per visit)	59
Clinical psychologist visit (per visit)	136
District nurse clinic visit (per visit)	38
Practice nurse visit (per visit)	19
Outpatient visit (per visit)	119
GP visit (per visit)	32	Picot et al.24
Very low calorie diet (per year)	67.20
Band removal	2540	NHS22
Revisional surgery	2540
Minor wound infection	695
Major wound infection	769
Deep vein thrombosis	443
Non-fatal pulmonary embolism	349
Laparoscopic cholecystectomy	1694
Incisional hernia repair	1691
Corticosteroids (per patient per year)	198	NIHCE28
Long-acting beta-adrenergic receptor agonists (per patient per year)	231
Complete/full blood count cost	2.78	NIHCE29
Liver function test (ALT and AST) cost	0.69	NIHCE30
Full lipid profile cost	1.60	NIHCE32
Metabolic bone disease test cost	69	NHS22
Nephrolithiasis test cost	3.13	NIHCE33

ALT, alanine transaminase; APAP, automatic positive airway pressure; AST, aspartate aminotransferase; CPAP, continuous positive airway pressure; HRG, Healthcare Resource Group; SMBG, self-monitoring of blood glucose.

Figure 1.  Cumulative incremental cost of LAGB relative to standard medical management. CI, confidence interval; GBP, 2010 pounds sterling; LAGB, laparoscopic adjustable gastric band.

Figure 2.  Total cost of treatment over 5 years with and without LAGB. GBP, 2010 pounds sterling; LAGB, laparoscopic adjustable gastric banding.

Table 5.  Sensitivity analysis results over a 5-year time horizon in a hypothetical cohort of 100 patients.

Analysis	Mean cost with SMM (95% CI), GBP	Mean cost with LAGB (95% CI), GBP	Mean budget impact (95% CI), GBP
Base case	909,955 (899,857 to 923,158)	818,668 (808,260 to 833,593)	−91,287 (−108,848 to −73,007)
Model settings
0% discounting	970,129 (959,005 to 985,058)	850,849 (839,708 to 866,974)	−119,280 (−138,553 to −98,828)
6% discounting	869,874 (860,036 to 882,651)	796,906 (787,384 to 811,060)	−72,967 (−89,233 to −55,623)
Cohort characteristics
Baseline BMI of 42.4 kg/m^2	911,215 (900,621 to 925,638)	819,399 (808,901 to 834,664)	−91,817 (−110,396 to −73,452)
Annual post-surgical BMI creep of 1.49 kg/m^2	918,936 (908,794 to 932,194)	841,099 (830,996 to 856,454)	−77,836 (−94,799 to −59,339)
Unit costs
All unit costs up 10%	1,001,292 (989,808 to 1,016,500)	900,263 (889,087 to 916,733)	−101,029 (−120,439 to −80,227)
All unit costs down 10%	819,124 (809,781 to 831,559)	736,619 (727,314 to 750,617)	−82,505 (−98,583 to −66,041)
Diabetes medication costs up 10%	937,706 (927,482 to 952,017)	827,157 (816,947 to 842,246)	−110,549 (−128,488 to −92,637)
Diabetes medication costs down 10%	882,740 (872,140 to 896,788)	810,003 (799,843 to 825,030)	−72,737 (−90,343 to −55,149)
Diabetes complication costs up 10%	913,462 (902,055 to 928,929)	821,277 (810,348 to 837,720)	−92,185 (−111,456 to −71,294)
Diabetes complication costs down 10%	906,989 (897,600 to 919,288)	815,961 (806,458 to 829,831)	−91,028 (−106,977 to −74,008)
Surgical complication costs up 10%	910,300 (900,009 to 924,342)	822,739 (812,460 to 837,878)	−87,561 (−105,273 to −69,101)
Surgical complication costs down 10%	909,996 (899,672 to 923,730)	814,441 (804,184 to 829,280)	−95,555 (−113,213 to −77,783)
Healthcare professional contact costs up 10%	956,145 (945,674 to 969,694)	853,609 (843,367 to 868,306)	−102,537 (−120,044 to −84,681)
Healthcare professional contact costs down 10%	864,100 (853,962 to 878,257)	783,503 (773,440 to 798,256)	−80,597 (−98,167 to −63,115)
Diabetes treatment assumptions
Mean insulin dose of 40 IU per patient per day	791,888 (781,421 to 806,045)	781,758 (771,524 to 796,974)	−10,131 (−27,792 to 8,068)
No self-monitoring of blood glucose costs	851,553 (841,177 to 865,396)	800,322 (790,083 to 815,213)	−51,231 (−68,259 to −32,801)
Other treatment
No sleep apnea costs	868,271 (858,159 to 881,742)	812,558 (802,268 to 828,062)	−55,714 (−72,988 to −37,408)
Abdominoplasty costs in 5% of LAGB patients	910,010 (899,790 to 923,634)	831,907 (821,572 to 847,105)	−78,103 (−95,347 to −59,488)

BMI, body mass index; CI, confidence interval; GBP, 2010 pounds sterling; LAGB, laparoscopic adjustable gastric banding.

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