Burden of illness among patients at high risk versus low risk for major cardiovascular events

Figures & data

Table 1.  Qualifying cardiovascular disease.

Cardiovascular disease	ICD-9 diagnosis codes, unless otherwise noted
Angina pectoris	413.xx
Myocardial infarction	410.xx, 412.xx
Hypertension	401.xx– 402, 405.xx
Ischemic heart disease	411.xx, 414.xx
Ischemic stroke	433.x1, 434.x1, 436.xx
Transient ischemic attack	435.xx
Multi-vessel percutaneous transluminal coronary angioplasty	Procedure codes: 00.66, 36.05 (ICD-9); 92981, 92984 (CPT)
Multi-vessel coronary artery bypass graft	Procedure codes: 36.10, 36.12–36.14 (ICD-9); 33534–33536, 33518–33523, 33511–33516 (CPT); S2206, S2209 (HCPCS)
Limb bypass surgery	Procedure codes: 39.25, 39.29 (ICD-9); 35510, 35512, 35516–35525, 35533, 35541–35558, 35565–35571, 35583–35587, 35616–35623, 35646–35661, 35665–35671, 35879–35881 (CPT)
Limb angioplasty	Procedure codes: 39.50 (ICD-9); 35456–35459, 35470, 35474–35475 (CPT)
Limb or foot amputation	Procedure codes: 84.0x–84.1x (ICD-9); 27590–27596, 27880–27888, 28800–28825 (CPT)
Diabetes with evidence of end organ damage defined as retinopathy, left ventricular hypertrophy, albuminuria	250.xx and one of the following: 250.5x, 362.0x, 362.1x, 429.3, 791.0, 593.6

Table 2.  Exclusionary conditions.

Exclusionary condition	ICD-9 diagnosis codes, unless otherwise noted
Congestive heart failure	428.xx
Aortic and mitral valve stenosis	396.xx
Asymmetric septal hypertrophy	745.2; Procedure code: 33416 (CPT)
Malfunctioning prosthetic valve	996.02
Constrictive pericarditis	391.xx; 4230xx, 423.xx
Congenital heart disease	746.xx
Heart transplant	V42.1, 996.83; Procedure codes: 33.6, 37.5 (ICD-9); 33930–33945, 0051T (CPT)
Hemorrhagic stroke	430.xx
Renal disease	585.xx, 403.xx–404.xx; Procedure codes: 90918–90925, E1500–E1699, G0257, G0308–G0330 (CPT)
Primary aldosteronism	255.10
Hereditary fructose intolerance
Pregnancy/delivery	Procedure codes: 72.0–72.39, 72.5x–72.9, 73.22, 73.5x, 74.xx (ICD–9); 59400–59410, 59510–59515, 59610–59614, 59618–59622 (CPT)

Table 3.  Demographics.

Demographic characteristic	HR55 (n = 26,005)	HR (n = 22,775)	LR (n = 278,107)
	n (%)	n (%)	n (%)
Age (years)
18–34	0 (0.00%)	1,665 (7.31%)	14,983 (5.39%)
35–44	0 (0.00%)	6,251 (27.45%)	49,036 (17.63%)
45–54	0 (0.00%)	14,859 (65.24%)	97,881 (35.20%)
55–64	16,396 (63.05%)	0 (0.00%)	83,203 (29.92%)
65+	9,609 (36.95%)	0 (0.00%)	33,004 (11.87%)
Gender
Female	10,504 (40.39%)	9,613 (42.21%)	131,918 (47.43%)
Male	15,501 (59.61%)	13,162 (57.79%)	146,189 (52.57%)
Race/ethnicity
Caucasian	17,224 (66.23%)	13,938 (61.20%)	176,548 (63.48%)
Black	1,170 (4.50%)	1,318 (5.79%)	17,773 (6.39%)
Hispanic	702 (2.70%)	1,108 (4.86%)	8,834 (3.18%)
Asian	189 (0.73%)	356 (1.56%)	2,873 (1.03%)
Other	155 (0.60%)	206 (0.90%)	1,638 (0.59%)
Missing	6,565 (25.25%)	5,849 (25.68%)	70,441 (25.33%)
High risk factor
Angina	9,924 (38.16%)	10,380 (45.58%)	0 (0.00%)
Myocardial infarction	6,581 (25.31%)	5,016 (22.02%)	0 (0.00%)
Ischemic stroke	5,052 (19.43%)	3,214 (14.11%)	0 (0.00%)
Transient ischemic attack	5,037 (19.37%)	3,726 (16.36%)	0 (0.00%)
High-risk diabetes	3,658 (14.07%)	2,862 (12.57%)	0 (0.00%)
Coronary artery bypass graft	1,088 (4.18%)	569 (2.50%)	0 (0.00%)
Angioplasty	639 (2.46%)	507 (2.23%)	0 (0.00%)
Limb angioplasty	441 (1.70%)	303 (1.33%)	0 (0.00%)
Limb/foot amputation	334 (1.28%)	314 (1.38%)	0 (0.00%)
Limb bypass	324 (1.25%)	171 (0.75%)	0 (0.00%)

Table 4.  Unadjusted healthcare utilization and costs.

Utilization/cost	HR55 (n = 26,005)	HR (n = 22,775)	LR (n = 278,107)
	n (%)	n (%)	n (%)
Ambulatory visits	25,750 (99.02%)	22,447 (98.56%)	274,335 (98.64%)
Emergency room visits	6,710 (25.80%)	6,279 (27.57%)	57,798 (20.78%)
Hospitalizations	7,872 (30.27%)	4,877 (21.41%)	41,370 (14.88%)
CVD-related ambulatory visits	22,172 (85.26%)	15,124 (66.41%)	220,528 (79.30%)
CVD-related emergency room visits	1,247 (4.80%)	827 (3.63%)	5,169 (1.86%)
CVD-related hospitalizations	5,375 (20.67%)	2,643 (11.60%)	18,824 (6.77%)
	Mean (SD)	Mean (SD)	Mean (SD)
Ambulatory visit count	34.32 (27.43)	28.28 (26.92)	24.29 (22.62)
CVD-related ambulatory visit count	6.75 (7.87)	3.95 (6.35)	3.68 (4.59)
Medical costs ($)	15,930 (30,132)	11,781 (26,663)	8,240 (19,501)
Pharmacy costs ($)	4,866 (4,915)	3,785 (5,455)	3,053 (4,119)
Total costs ($)	20,796 (31,420)	15,566 (28,511)	11,294 (20,771)
CVD-related medical costs ($)	7,402 (27,732)	4,165 (17,279)	2,330 (15,743)
CVD-related pharmacy costs ($)	1,774 (1,774)	1,087 (1,589)	812 (1,146)
CVD-related total costs ($)	9,176	5,252	3,142

Table 5.  Adjusted outcomes relative to low-risk patients.

Utilization/cost		Coefficient	Ratio	Robust SE	95% Lower CI	95% Upper CI	p-value
Ambulatory visits	High risk + 55	0.0578	1.0595	0.0072	1.0445	1.0746	0.000
	High risk	0.1030	1.1085	0.0074	1.0925	1.1247	0.000
CVD-related ambulatory visits	High risk + 55	0.2689	1.3085	0.0078	1.2887	1.3286	0.000
	High risk	0.1687	1.1837	0.0083	1.1647	1.2030	0.000
Inpatient stays	High risk + 55	0.3333	1.3955	0.0165	1.3511	1.4414	0.000
	High risk	0.4427	1.5570	0.0185	1.5016	1.6144	0.000
CVD-related inpatient stays	High risk + 55	0.5000	1.6487	0.0194	1.5872	1.7127	0.000
	High risk	0.8120	2.2525	0.0247	2.1462	2.3641	0.000
Total costs	High risk + 55	0.1058	1.1116	0.0071	1.0962	1.1273	0.000
	High risk	0.2335	1.2630	0.0073	1.2451	1.2813	0.000
Total CVD-related costs	High risk + 55	0.3789	1.4607	0.0074	1.4397	1.4820	0.000
	High risk	0.6889	1.9916	0.0082	1.9597	2.0240	0.000

Covariates used for the adjusted analysis included: HR55 and HR (LR as the reference group), Charlson Comorbidity Index score; male gender (female as reference); age 55–64, age 65+ (age <55 as reference); and Caucasian race (non-Caucasian as reference).