Adherence rates and health care costs in Crohn’s disease patients receiving certolizumab pegol with and without home health nurse assistance: results from a retrospective analysis of patient claims and home health nurse data

Figures & data

Table 1 Baseline demographics and clinical characteristics of the matched populationa

Characteristics	CZP with nurse assistance (n=417)	CZP without nurse assistance (n=417)	P-value
Age (continuous), mean (SD), years	39.1 (12.0)	38.9 (12.4)	0.8290
Gender, n (%)
Female	232 (55.6)	232 (55.6)	1.0000
Male	185 (44.4)	185 (44.4)	1.0000
Payer type, n (%)
Commercial	228 (54.7)	238 (57.1)	0.2558
Self-insured	187 (44.8)	173 (41.5)
Medicaid	2 (0.5)	6 (1.4)
Charlson comorbidity indexb, mean (SD)	0.46 (0.99)	0.40 (0.77)	0.3114
Medication history, n (%)
Corticosteroids	312 (74.8)	317 (76.0)	0.6876
TNF antagonists	208 (49.9)	227 (54.4)	0.1878
Monoclonal antibodies	2 (0.5)	1 (0.2)	0.5630
Methotrexate	14 (3.4)	24 (5.8)	0.0968
Thiopurines	149 (35.7)	137 (32.9)	0.3814
Anti-anxiety medication	145 (34.8)	136 (32.6)	0.5097
Antidepressants	127 (30.5)	120 (28.8)	0.5955
Hospitalizations, mean (SD)	0.57 (1.07)	0.57 (1.19)	0.9755
History of CD-related surgery, n (%)
≥1 surgery	303 (72.7)	285 (68.3)	0.1717

Notes:

a Exact matching was performed using gender and categorical age, with a 1:1 ratio of cases to controls.

b Dartmouth–Manitoba adaptation of the Charlson comorbidity index.²⁶

Abbreviations: CD, Crohn’s disease; CZP, certolizumab pegol; SD, standard deviation; TNF, tumor necrosis factor.

Figure 1 Adherence to CZP therapy using the PDC and MPR measures with and without nurse assistance.

Abbreviations: CZP, certolizumab pegol; MPR, medication possession ratio; PDC, proportion of days covered.

Table 2 Adherence and persistence with certolizumab pegol therapy with and without nurse assistance

Compliance parameter	CZP with nurse assistance (n=276)	CZP without nurse assistance (n=276)	P-value
PDC
Mean (SD)	0.62 (0.29)	0.54 (0.32)	0.0029
Median (min–max)	0.73 (0.04–1.00)	0.60 (0.04–1.00)	0.0086
MPR
Mean (SD)	0.65 (0.30)	0.57 (0.33)	0.0029
Median (min–max)	0.78 (0.04–1.00)	0.62 (0.04–1.00)	0.0058
Adherence to treatment, n (%)
Patients with PDC ≥80%	111 (40.2)	93 (33.7)	0.1125
Patients with MPR ≥80%	125 (45.3)	103 (37.3)	0.0572
Persistance with treatment, n (%)	139 (50.4)	116 (42.0)	0.0496
Duration of persistance (days)
Mean (SD)	240.8 (132.9)	215.6 (139.4)	0.0304
Median (min–max)	360 (14–360)	223.5 (14–360)	0.0200

Abbreviations: CZP, certolizumab pegol; max, maximum; min, minimum; MPR, medication possession ratio; PDC, proportion of days covered; SD, standard deviation.

Figure 2 Kaplan–Meier curves comparing time to discontinuation of treatment.

Note: Data are presented up to 3 years of follow-up; patients were censored at the end of the 3 years.
Abbreviation: CZP, certolizumab pegol.

Table 3 The effect of nurse assistance on hospitalizations and total health care costs

Outcome measure	CZP with nurse assistance (n=276)	CZP without nurse assistance (n=276)
Total hospitalizations	151	203
Hospitalizations per patient
Mean (SD)	0.55 (1.2)	0.74 (1.3)
Median	0.00	0.00
Min, max	0.00, 10.0	0.00, 10.0
Total cost of hospitalizations (US$)	2,776,751	4,305,173
Cost per patient (US$)
Mean (SD)	10,060.69 (43,935.1)	15,598.45 (43,650.0)
Median	0.00	0.00
Min, max	0.00, 646,048.41	0.00, 603,299.28
Patients with at least one hospitalization	77 (27.9)	107 (38.8)
Hospitalization per patient
Mean (SD)	1.96 (1.6)	1.90 (1.5)
Median	1.00	1.00
Min, max	1.00, 10.00	1.00, 10.00
Length of stay
Mean (SD)	11.70 (17.5)	10.95 (13.2)
Median	6.00	7.00
Min, max	1.00, 127.00	2.00, 95.00
Total cost of hospitalizations per patient (US$)
Mean (SD)	36,061.70 (77,683.00)	40,235.26 (62,788.80)
Median	21,448.79	25,001.22
Min, max	540.35, 646,048.41	2,618.98, 603,299.28
Total health care cost (US$)	14,716,874.59	17,147,109.00
Total health care cost per patient (US$)
Mean (SD)	53,322.01 (56,509.47)	62,127.21 (75,439.05)
Median	40,929.39	44,445.47
Min, max	6,346.47, 746,142.94	1,824.45, 863,539.00

Abbreviations: CZP, certolizumab pegol; max, maximum; min, minimum; SD, standard deviation.

Table 4 Multivariate regression analysis evaluating the impact of certolizumab pegol in combination with other covariates on hospitalization costs

Variable	Parameter coefficient	Exp (coefficient)	% change reduction/increase	Standard error	P-value
CZP with nurse assistance (ref: without)	−0.817	0.442	−55.8	0.272	0.0026
Plan type (other vs PPO)	0.414	1.513	51.3	0.417	0.3211
Payer type (other vs commercial)	0.418	1.519	51.9	0.288	0.1461
Geographic region (ref: South)
Northeast	−0.160	0.852	−14.8	0.376	0.6704
Midwest	0.285	1.329	32.9	0.335	0.3956
West	−0.896	0.408	−59.2	0.717	0.2114
Comorbid condition (yes vs no)
ASCVD	−0.416	0.660	−34.0	0.609	0.4949
Asthma	−0.330	0.719	−28.1	0.498	0.5079
COPD	0.366	1.442	44.2	0.770	0.6343
Cancer	0.145	1.157	15.7	0.434	0.7374
Hypertension	−0.186	0.830	−17.0	0.433	0.6675
Diabetes	1.089	2.970	197.0	0.851	0.2005
Medication history (yes vs no)
Corticosteroids	0.336	1.400	40.0	0.332	0.3106
TNF antagonists	0.436	1.546	54.6	0.274	0.1113
Methotrexate	0.423	1.526	52.6	0.745	0.5702
Thiopurines	−0.168	0.846	−15.4	0.308	0.5860
Anti-anxiety medication	0.654	1.923	92.3	0.309	0.0344
Number of prior hospitalizations	0.371	1.450	45.0	0.137	0.0067
History of surgery (yes vs no)
Patients with ≥1 surgery	−0.232	0.793	20.7	0.299	0.4373

Abbreviations: ASCVD, atherosclerotic cardiovascular disease; COPD, chronic obstructive pulmonary disease; CZP, certolizumab pegol; Exp, exponentiated; PPO, preferred provider organization; ref, reference; TNF, tumor necrosis factor.

Table 5 Multivariate regression analysis evaluating the impact of certolizumab pegol in combination with other covariates on total health care costs

Variable	Parameter coefficient	Exp (coefficient)	% change reduction/increase	Standard error	P-value
CZP with nurse activity (ref: without)	−0.154	0.857	−14.3	0.054	0.0045
Plan type (other vs PPO)	0.051	1.053	5.3	0.085	0.5443
Payer type (other vs commercial)	0.059	1.061	6.1	0.056	0.2884
Geographic region (ref: South)
Northeast	−0.085	0.919	−8.1	0.074	0.2508
Midwest	0.141	1.152	15.2	0.067	0.0347
West	0.077	1.080	8.0	0.143	0.5909
Comorbid condition (yes vs no)
ASCVD	0.152	1.164	16.4	0.110	0.1699
Asthma	−0.083	0.921	−7.9	0.099	0.4040
COPD	0.069	1.072	7.2	0.155	0.6559
Cancer	0.095	1.100	10.0	0.083	0.2536
Hypertension	−0.126	0.881	−11.9	0.078	0.1055
Diabetes	0.364	1.439	43.9	0.145	0.0119
Medication history (yes vs no)
Corticosteroids	0.031	1.031	3.1	0.065	0.6382
TNF antagonists	0.246	1.279	27.9	0.055	<0.0001
Methotrexate	0.014	1.014	1.4	0.140	0.9191
Thiopurines	−0.095	0.910	−9.0	0.058	0.0995
Anti-anxiety medication	0.221	1.247	24.7	0.060	0.0002
Number of prior hospitalizations	0.109	1.116	11.6	0.025	<0.0001
History of surgery (yes vs no)
Patients with ≥1 surgery	−0.037	0.964	−3.6	0.061	0.5447

Abbreviations: ASCVD, atherosclerotic cardiovascular disease; COPD, chronic obstructive pulmonary disease; CZP, certolizumab pegol; Exp, exponentiated; PPO, preferred provider organization; ref, reference; TNF, tumor necrosis factor.

CharlsonMSzatrowskiTPPetersonJGoldJValidation of a combined comorbidity indexJ Clin Epidemiol19944711124512517722560

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