A modeled economic evaluation of sevelamer for treatment of hyperphosphatemia associated with chronic kidney disease among patients on dialysis in the United Kingdom

Figures & data

Figure 1.  Model health states and transitions.

Table 1.  Summary of base case analysis inputs, assumptions, and data sources.

Analysis parameter	Base case input	Data sources
Mean age of starting cohort (years)	60	Suki et al.19
Perspective	UK NHS	N/A
Discounting (%)	3.5	NICE36
Overall survival
Up to 44 months	Figure 2	Suki et al.19
Beyond 44 months	Figure 2	Weibull regression
Hospitalization (mean number of days per patient per year)
Calcium carbonate	17.4	Suki et al.19
Sevelamer carbonate	14.8^a	Suki et al.19
Drug dose (grams per day)
Calcium acetate	5.3^b	Suki et al.19
Calcium carbonate	4.9^b	Suki et al.19
Sevelamer carbonate	6.9	Suki et al.19
Unit costs (£)
Sevelamer (per gram)	0.8191	BNF28
Calcium carbonate  (per gram)	0.0483	BNF28
Calcium acetate  (per gram)	0.11	BNF28
Hospitalization  (per patient  bed day)	359.15^c	National Schedule of Reference Costs 2007–200829
Utility
Patient with ESRD	0.61^d	Dale et al.30

BNF, British National Formulary; ESRD, end-stage renal disease; N/A, not applicable; NHS, National Health Service; NICE, National Institute for Clinical Excellence; UK, United Kingdom.

^a Calculated by multiplying the relative risk (RR) for the sevelamer group in DCOR (RR = 0.85) by the mean hospital days per year reported in DCOR for the calcium-based binder group (17.4).

^b Based on Suki et al.19, it was assumed that 70% of patients in the calcium-based group received calcium acetate and 30% received calcium carbonate.

^c Calculated as a weighted average cost per day of hospitalization based on data regarding any hospitalization code specific to a patient with chronic renal failure, including hospitalizations for elective and non-elective procedures.

^d Calculated as a weighted average of five studies with a quality score of 4 or more, as reported by Dale et al.30 in their systematic review of utility estimates for health states in CKD.

Figure 2.  Overall survival of patients in the DCOR study (up to 44 months), extrapolated using Weibull regression analysis, shown to 20 years. CBBs, Calcium-based binders.

Table 2.  Base case cost of a hospitalized day.

Currency code	Currency description	Activity	National average unit cost (£)	No. of bed days	Average length of stay (LOS) in days	Total cost (unit cost ×  activity) (£)	Cost per day (total cost/LOS) (£)
Elective inpatient HRG data
EB01Z	Non-interventional acquired cardiac conditions 19 years and over	4976	1208	10,823	2.18	6,012,136	2,764,149
EB05Z	Cardiac arrest	81	1375	291	3.59	111,337	30,991
EB10Z	Actual or suspected myocardial infarction	4094	1934	13,899	3.39	7,919,161	2,332,617
LA08A	CRF with length of stay 2 days or more with major CC	289	3486	3032	10.49	1,007,340	96,016
LA08B	CRF with length of stay 2 days or more with intermediate CC	889	2299	5190	5.84	2,043,954	350,111
LA08C	CRF with length of stay 2 days or more without CC	617	1952	2844	4.61	1,204,386	261,289
LA08D	CRF with length of stay 1 day or less	6075	431	6504	1.07	2,620,743	2,447,880
Non-elective inpatient (long stay) HRG data
EB01Z	Non interventional acquired cardiac conditions 19 years and over	124,405	950	354,665	2.85	118,220,515	41,467,929
EB05Z	Cardiac arrest	1251	1686	6480	5.18	2,109,512	407,253
EB10Z	Actual or suspected myocardial infarction	71,478	1523	382,831	5.36	108,868,174	20,326,670
LA08A	CRF with length of stay 2 days or more with major CC	2856	3283	33,470	11.72	9,375,586	800,020
LA08B	CRF with length of stay 2 days or more with intermediate CC	4485	2140	32,885	7.33	9,596,929	1,308,871
LA08C	CRF with length of stay 2 days or more without CC	1278	2027	7958	6.23	2,589,963	415,930
LA08D	CRF with length of stay 1 day or less	797	844	1908	2.39	672,946	281,100
Non-elective inpatient (short stay) HRG data
EB01Z	Non interventional acquired cardiac conditions 19 years and over	255,411	342	255,411	1.00	87,284,557	87,284,557
EB05Z	Cardiac arrest	1480	367	1480	1.00	542,894	542,894
EB10Z	Actual or suspected myocardial infarction	35,669	381	35,669	1.00	13,584,685	13,584,685
LA08A	CRF with length of stay 2 days or more with major CC	5	555	5	1.00	2773	2773
LA08B	CRF with length of stay 2 days or more with intermediate CC	9	536	9	1.00	4824	4824
LA08C	CRF with length of stay 2 days or more without CC	2	619	2	1.00	1239	1239
LA08D	CRF with length of stay 1 day or less	17,164	204	17,164	1.00	3,508,238	3,508,238
Weighted mean cost per hospitalized day (£)							334.18
Weighted mean cost per hospitalized day, adjusted for inflation (£)							359.15

CRF, chronic renal failure; CC, complications; HRG, Healthcare Resource Group; LOS, length of stay.

Table 3.  Summary of the utility studies used to determine the weighted average base case utility value for patients with ESRD receiving dialysis.

Reference	Country	Assessment technique	Quality score	Number of patients	Utility estimate
Bass et al.31	US	TTO	4	188	0.69
De Witt et al.32	Netherlands	EQ-5D	5	165	0.66
Gorodetskaya et al.33	US	TTO	4	205	0.54
Manns et al.34	Canada	EQ-5D	5	192	0.62
Sennfalt et al.35	Sweden	EQ-5D	4	81	0.44

EQ-5D, EuroQol-5D; TTO, Time trade off; US, United States.

Table 4.  Discounted base case cost-effectiveness results for sevelamer compared with calcium-based binders, considering a lifetime horizon.

Analysis, treatment	Cost per patient (£)	Incremental cost per patient (£)	Total life years per patient	Incremental life years per patient	Incremental cost per life year gained (£)
Cost-utility analysis (cost per QALY gained)
Calcium-based binders	29,856	–	2.8164	–	–
Sevelamer	39,701	9845	3.2608	0.4443	22,157
Cost-effectiveness analysis (cost per life year gained)
Calcium-based binders	29,856	–	4.6476	–	–
Sevelamer	39,701	9845	5.3808	0.7332	13,427

QALY, quality-adjusted life year.

Figure 3.  Tornado diagram displaying results of one-way sensitivity analyses. Results are presented as incremental costs per QALY gained (£) for sevelamer vs calcium-based binders.

Figure 4.  Incremental cost-effectiveness ratios for age sub-group populations of DCOR, including patients aged ≥45, ≥50, ≥55, and ≥65 years.

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