Echo-based screening of rheumatic heart disease in children: a cost-effectiveness Markov model

Figures & data

Figure 1. Model diagram of relevant health states.

Table 1. Initial state distributions and Echo screen results.

	Webb et al.13	Marijon et al.8	Reeves et al.9	Beaton et al.7	Bhaya et al.12	Saxena et al.11	Weighted probability ± SE
n	1142	2170	362	4869	1059	6270
Sub-clinical RHD	55	61	16	49	53	123	0.017,095,96 ± 0.001,026,014
Clinical RHD	4	5	4	23	1	5	0.001,404,44 ± 0.000,297,071
Echo Screen positive	95	124	99	130			0.037,015,469 ± 0.002,022,628
True Positive Screen	62%	53%	20%	55%			45.605,483,6 ± 2.212,980,6%
False Positive Screen	38%	47%	80%	45%			54.394,516,4 ± 2.212,980,6%

Table 2. Annual transition probabilities.

Transition states	Age	Yearly probability^a
Subclinical RHD to RHD CHF26–28		0.025,824,67 ± 0.008,261,654
Clinical RHD/Resolved RHD to CHF*		0.012,912,34 ± 0.008,259,597
Clinical RHD to Resolved RHD on Prophylaxis29–34		0.087,325,441 ± 0.015,435,476
RHD CHF to Dead32^,35		0.061,010,739 ± 0.014,796,559
Sub-clinical RHD to Well11^,12		0.100,289,612 ± 0.063,021,044
Sub-clinical RHD to Clinical RHD28^,35		0.028,248,41 ± 0.010,411,038
RHD surgery perioperative mortality36		0.012,345,679
RHD pVR to Dead36		0.028,358,342 ± 0.006,432,767
RHD CHF to RHD pVR23^,37		0.128,468,899 ± 0.0813
Prophylaxis mortality38		0.001,480,202
Well to Clinical RHD39	5–9	0.000,599
	10–14	0.000,884
	15–19	0.002,123
	20–24	0.003,112
	25–29	0.005,067
	30–34	0.002,711
	35–39	0.003,534
	40–44	0.003,433
	45–49	0.002,993
Well to Sub-clinical RHD11	5–10	0.002,532
	11–15	0.002,907
	15+	0.000,634#
Well to RHD CHF40	5–9	3.722,67 × 10^−5
	10–14	4.553,66 × 10^−5
	15–19	2.130,59 × 10^−5
	20–24	1.356,54 × 10^−5
	25–29	7.947,68 × 10^−6
	30–34	9.319,79 × 10^−7
	35–39	2.252,28 × 10^−6
	40–44	3.365,47 × 10^−6
	45–49	4.038,57 × 10^−6
Well to Dead41	5–9	0.000,199,96
	10–14	0.000,399,84
	15–19	0.000,499,75
	20–24	0.001,198,561
	25–29	0.000,999,001
	30–34	0.001,298,311
	35–39	0.003,189,787
	40–44	0.002,991,022
	45–49	0.004,677,996
Clinical RHD to Dead40	5–14	0
	15–19	1.448,14 × 10^−6
	20–24	3.519,65 × 10^−6
	25–29	7.315,82 × 10^−7
	30–34	6.606,37 × 10^−7
	35–39	4.064,95 × 10^−6
	40–44	2.597,26 × 10^−6
	45–49	2.735,38 × 10^−6
Acute Rheumatic Fever to Dead40	5–9	1.999,96 × 10^−5
	10–19	3.399,88 × 10^−5

^aEstimated as a weighted average ± standard error.

*Assuming 50% reduction from preprophylaxis era.

#Assuming 25% of 5–10 year old stratum.

Table 3. Costs by health state per person per year in 2010 Australian dollars.

	Component cost	Total state cost
Well or Subclinical RHD		152
GP visit	22
Transport to GP	10
Lost wages	120
Clinical RHD or Resolved RHD		680
GP visit	22
Transport to GP	10
Lost wages	120
Penicillin	103
Syringe, needles, sterile diluent	6
Lignocaine 2%	4
Prophylaxis staff salary	405
Prophylaxis transport	124
RHD CHF		16,054
GP visit	87
Transport to GP	41
Cardiologist visit	60
Transport to Cardiologist at referral center	52
Penicillin	103
Syringe, needles, sterile diluent	6
Lignocaine 2%	4
Prophylaxis staff salary	405
Prophylaxis transport	124
Enalapril 20mg	204
Frusemide 40mg	30
Lost wages	15000
RHD pVR		16,757
GP visit	87
Transport to GP	41
Cardiologist visit	60
Transport to Cardiologist at referral center	52
Penicillin	103
Syringe, needles, sterile diluent	56
Lignocaine 2%	4
Prophylaxis staff salary	405
Prophylaxis transport	124
Enalapril 20mg	204
Frusemide 40mg	30
Coumarin 5mg	102
INR monitoring	600
Lost wages	15,000

Table 4. Cost inputs per person per event in 2010 Australian dollars.

	Component cost	Total cost
One time events
Echo screening		146.21
Screening Echo machine**	13.65
Screening staff salary42	10.81
Screener training (one-time)43	0.96
Screener transport (roundtrip)16^,17	10.36
Cardiologist overread of echo#44	3.93
Cardiologist visit and  echo for Screen Positive44	59.93
Transport to Cardiologist at  referral center (roundtrip)16^,17	103.50
Valve Replacement		23,657.49
Mitral valve**	960.83
Operation Theater45	9,755.18^a
ICU – 2 days45	5,052.73
Hospital – 10 days45	3700
Rehabilitation – 1 day45	537
Transport to referral  center (roundtrip)16^,17	103.50
30 days of lost wages46	3,600
Repeated costs
Daily minimum wage46	120
General practitioner visit47	21.66
Transport for general practitioner  or prophylaxis (one trip)16^,17	10.36
Transport to referral  center (roundtrip)16^,17	103.50
Penicillin- 600mg vials × 248	8.58
Syringe, needles, sterile diluent	0.47
Lignocaine 2% 5cc vial- 0.5cc  used per injection49	0.74
Prophylaxis staff salary (per injection)42	33.74
Enalapril 20mg tablet50	0.56
Frusemide 40mg tablet51	0.083
Coumarin 5mg tablet52	0.28
Monthly INR monitoring53	50

**Personal communication.

^aOperation theater Includes room, consumables, staff salaries.

Table 5. Average per person costs (2010 Australian dollars) and QALYs.

	Screen	No screen	Difference (95% CI)	Cost/QALY (Screen vs No screen)
Point estimates
Total societal cost	$7749	$8181	−$432 (−$1357 to 575)	Dominates
Health care costs only	$1799	$1774	$25 (−$117 to 176)	$3571
Quality adjusted life years	19.16	19.15	0.007 (−0.010 to 0.024)
PSA comparing Screen vs No screen
% Dominant	81.0%
% Lower costs and QALYs	1.2%
% Dominated	16.6%
% ICER >64,000/QALY	1.1%
% ICER ≤64,000/QALY	0.1%

PSA, Probabilistic sensitivity analyses, 5000 simulations; QALY, Quality-adjusted life year; ICER, Incremental cost-effectiveness ratio.

Figure 2. Cost-effectiveness plane for incremental change of Screen strategy over No screen. Incremental benefit is along the x-axis and incremental cost in on the y-axis. Toward the right indicates more QALYs and toward the top indicates higher cost.

Table 6. One-way sensitivity analyses for ICER of Screen vs No screen.

Cost inputs	Range	Low ICER	High ICER
Daily Wage	39.6–360	−187,329	−17,451
Short Term Prophylaxis Staff Salary	133–1214	−65,385	−44,242
Operating Room	3219–29,265	−67,021	−57,754
Short Term Prophylaxis Penicillin	33–308	−61,429	−56,052
Echo Machine	4.5–40	−61,351	−56,282
Intensive Care Unit Day	813–7398	−63,588	−58,904
Lifelong Prophylaxis Staff Salary	133–1214	−63,509	−58,930
INR (International Normalized Ratio)	198–1800	−63,132	−59,057
Echo Screen Staff Salary	3.6–32	−61,087	−57,072
Transport to Screening	3–31	−61,045	−57,197
Inpatient Ward Day	122–1110	−62,712	−59,197
Enalapril	67–613	−61,811	−59,499
Cardiology Quality Control	1.3–11	−60,445	−58,986
Lifelong Prophylaxis Penicillin	33–308	−60,951	−59,787
Heart Valve	317–2882	−60,763	−59,850
General Practitioner Visit	7.1–64	−60,614	−59,900
Coumarin	33–306	−60,599	−59,905
Transport for Short Term Prophylaxis	41–372	−60,215	−59,674
Screen Staff Training	0.31–2.8	−60,169	−59,812
Frusemide	9.9–90	−60,336	−59,993
Transport to General Practitioner	3–31	−60,335	−59,994
Transport to Referral Hospital	34–310	−60,154	−59,855
Short Term Prophylaxis Paraphernalia	1.9–16	−60,153	−59,859
Short Term Prophylaxis Lignocaine	1.4–13.3	−60,137	−59,906
Cardiology Visit	19–179	−60,123	−59,950
Transport for Lifelong Prophylaxis	41–372	−60,167	−60,050
Lifelong Prophylaxis Paraphernalia	1.9–16	−60,127	−60,063
Lifelong Prophylaxis Lignocaine	1.4–13.2	−60,117	−60,067

ICER, Incremental cost-effectiveness ratio.

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