Disease-specific cost savings of treating nighttime versus daytime gastroesophageal reflux disease in an employed population

Figures & data

Figure 1.  Scheme for economic model comparing costs for PPI treatment versus no treatment.

Table 1.  Model parameters.

Parameter	Base value (%)	Range (%)	Reference
GERD prevalence	20	–	14
Proportion that are DG	50	–	Assumption based on 15
Proportion that are NG	50	–	Assumption based on 15
Baseline population distribution by GERD symptom severity
GERD
Mild	42.7	–	17
Moderate	45.4	–	17
Severe	11.9	–	17
DG
Mild	52.0	–	15
Moderate	42.5	–	15
Severe	5.5	–	15
NG
Mild	33.5	–	15
Moderate	48.4	–	15
Severe	18.1	–	15
% symptom relief at 4 weeks
PPI	56	26–84	18–28 and expert opinion
No treatment (placebo)	24	4–44*	18,19 and expert opinion
% breakthrough symptoms after 6 months
PPI	25	5–55^†	29–31 and expert opinion
No treatment (placebo)	78	62–90	29,31 and expert opinion
% symptomatic relief on double dose of PPI	77	35–92	21,22,24,25,27,32–45 and expert opinion
Distribution of symptom severity on treatment relapse
% mild	26	–	Expert opinion
% moderate	40	–	Expert opinion
% severe	34	–	Expert opinion
Cost parameters
Standard-dose PPI (daily)	$2	$1–$5	46
Hourly wage	$17.80‡	$8.91–$25.63^‡	48

GERD, gastroesophageal reflux disease; DG, daytime GERD; NG, nighttime GERD; PPI, proton pump inhibitor.

*The range chosen in the sensitivity analysis was ± 20% from the base case value because the two cited studies only included patients with NG.

^†The range chosen in the sensitivity analysis was ± 20% from the base case value because all cited studies only included patients with erosive oesophagitis.

^‡The base case value was based on the national average of all industry types. The low end of the sensitivity range was based on the ‘leisure & hospitality’ industry and the high end was based on the ‘utility’ industry.

Table 2.  Self-reported utilisation per patient by GERD severity.

Self-reported utilisation per patient over the past 6 months	GERD severity			All*
	Mild	Moderate	Severe
Mean total hospitalisation days	0.019	0.021	0.030	0.023
Mean total times received ER care	0.026	0.038	0.173	0.066
Mean total no. of medical office visits	0.245	0.484	1.524	0.682
Mean no. of pH testing procedures	0.013	0.003	0.012	0.007
Mean no. of oesophageal testing procedures	0.006	0.003	0.012	0.006
Mean no. of oesophageal dilation procedures	0.013	0.006	0.030	0.013
Mean no. of gastric emptying study procedures	0.000	0.012	0.024	0.013
Mean no. of upper GI endoscopy procedures	0.058	0.047	0.113	0.067
Mean no. of endoscopy for anti-reflux procedures	0.013	0.018	0.042	0.026
Mean no. of upper GI radiography procedures	0.052	0.050	0.077	0.060

GERD, gastroesophageal reflux disease; ER, emergency room; GI, gastrointestinal. * This category represents all severity strata combined.

Table 3.  Unit costs for hospitalisation, medical visits and procedures.

Service	Code	Unit cost ($)*
GERD-related hospitalisation	DRG 155	5,788.4952
GERD-related ER visit	CPT 99285	161.2653
GERD-related office visit	CPT 99212	25.9353
Oesophageal acid testing (24-hour oesophageal pH test or capsule pH testing)	CPT 91034	270.6753
Oesophageal motility testing	CPT 91010	245.7353
Oesophageal dilation	CPT 4350, 4353, 4356, 4358	131.94^†53
Gastric emptying study	CPT 78264	230.8753
Upper GI endoscopy	CPT 43235	146.2253
Endoscopy to perform an anti-reflux procedure	CPT 43235	146.2253
Upper GI radiography that involves drinking barium	CPT 74246	113.4253

GERD, gastroesophageal reflux disease; DRG, diagnosis related group; ER, emergency room; CPT, common procedural terminology; GI, gastrointestinal.

* Costs are reported in 2005 US dollars.

^† The average among CPT codes 4350, 4353, 4356 and 4358.

Table 4.  Relative utilisation weights.

GERD severity stratum	Total costs of medical and procedure during the past 3 months ($)*	Relative utilisation weight	Estimated annual costs of GERD-related medical and procedure ($)
Mild	72.78 (A)	0.771^†	185
Moderate	78.80 (B)	0.835^‡	200
Severe	143.30 (C)	1.519^$	364
All	94.36 (D)	1.000 (reference)	240 (reference)^¶

GERD, gastroesophageal reflux disease.

* Costs were derived from utilisation data obtained from the Internet-based survey reported in Table 2 but were estimated for a 3-month time period by dividing by 2 then multiplying by the unit cost reported in Table 3.

^†Weight derived by dividing A by D.

^‡Weight derived by dividing B by D.

^$Weight derived by dividing C by D.

^¶The reference value of $240 was based on an analysis of claims data3.

Table 5.  Work productivity impairment by severity and GERD type54.

GERD severity	GERD (n=1,002)		DG (n=469)*		NG (n=475)*
	GERD WPAI (%)	Hours lost^†	GERD WPAI (%)	Hours lost^†	GERD WPAI (%)	Hours lost^†
Mild	4.6	1.8	3.3	1.3	6.6	2.6
Moderate	11.4	4.6	7.7	3.1	14.5	5.8
Severe	15.3	6.1	11.5	4.6	16.4	6.6

GERD, gastroesophageal reflux disease; DG, daytime GERD; NG, nighttime GERD; WPAI, Work Productivity and Activity Impairment.

*Fifty-eight cases were excluded because missing data did not permit assignment of DG and NG. Therefore, the results reported for GERD are not the arithmetic means of the DG and NG results.

^† The number of hours lost was calculated by multiplying the GERD WPAI percentage by a 40-hour work week (assumed).

Table 6.  Annual economic impact of treating GERD with proton pump inhibitors*.

Costs ($)^†	GERD (n=20,000)^‡
	Treatment	No treatment
Direct costs	21,073,248	4,505,187
Indirect costs	8,849,039	58,021,412
Total	29,922,287	62,526,599
Net savings	32,604,312
Savings per treated patient per year	1,630

GERD, gastroesophageal reflux disease.

*Based on a population of 100,000.

^†Costs reported in 2005 US dollars.

^‡The economic impact of treatment for GERD was derived from inputs specific for the GERD group rather than based on inputs from daytime GERD and nighttime GERD.

Table 7.  Comparison of the economic impact of treatment with proton pump inhibitors* among DG versus NG.

Costs ($)^†	DG (n=10,000)		NG (n=10,000)
	Treatment	No treatment	Treatment	No treatment
Direct costs	10,525,939	2,161,981	10,547,164	2,340,596
Indirect costs	2,840,527	18,536,187	6,780,510	38,858,299
Total	13,366,465	20,698,168	17,327,674	41,198,895
Net savings	7,331,703		23,871,221
Savings per treated patient per year	733		2,387

DG, daytime gastroesophageal reflux disease; NG, nighttime gastroesophageal reflux disease.

*Based on a population of 100,000.

^† Costs were reported in 2005 US dollars.

Figure 2.  Tornado diagram of key parameters showing per patient savings from treatment of gastroesophageal reflux disease with PPIs.

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