Healthcare resource usage of schizophrenia patients initiating long-acting injectable antipsychotics vs oral

Figures & data

Table 1.  Baseline demographics of commercially and Medicare insured LAI and oral cohorts.

Variable	Commercial population						p-value	Medicare population					p-value
	LAI			Oral				LAI		Oral
Total patient count	394			2610				147		518
Age							<0.001						<0.001
Mean	41.7			37.1				67.2		73.2
SD	15.5			15.9				9.8		10.0
Median	46			38				68		74
	n		%	n		%		n	%	n		%
Age group (years)							<0.001						<0.001
≤17	11	2.8%		292	11.2%			0	0.0%	0	0.0%
18–35	136	34.5%		944	36.2%			0	0.0%	0	0.0%
36–45	45	11.4%		376	14.4%			0	0.0%	2	0.4%
46–55	99	25.1%		585	22.4%			20	13.6%	31	6.0%
56–65	103	26.1%		413	15.8%			36	24.5%	58	11.2%
66–75	0	0.0%		0	0.0%			61	41.5%	191	36.9%
≥76	0	0.0%		0	0.0%			30	20.4%	236	45.6%
Gender							0.577						0.142
Male	204	51.8%		1312	50.3%			59	40.1%	174	33.6%
Female	190	48.2%		1298	49.7%			88	59.9%	344	66.4%
Region							<0.001						<0.001
North East	44	11.2%		294	11.3%			9	6.1%	71	13.7%
North Central	185	47.0%		769	29.5%			98	66.7%	232	44.8%
South	126	32.0%		874	33.5%			36	24.5%	129	24.9%
West	37	9.4%		649	24.9%			4	2.7%	81	15.6%
Unknown	2	0.5%		24	0.9%			0	0.0%	5	1.0%
Health plan type							<0.001						0.088
Comprehensive	74	18.8%		256	9.8%			76	51.7%	269	51.9%
EPO	2	0.5%		21	0.8%			0	0.0%	0	0.0%
HMO	70	17.8%		681	26.1%			2	1.4%	31	6.0%
POS	38	9.6%		338	13.0%			5	3.4%	15	2.9%
PPO	196	49.8%		1224	46.9%			63	42.9%	201	38.8%
POS/CP	2	0.5%		6	0.2%			0	0.0%	0	0.0%
CDHP	10	2.5%		53	2.0%			1	0.7%	0	0.0%
Unknown	2	0.5%		31	1.2%			0	0.0%	2	0.4%
Index drug							<0.001						<0.001
Aripiprazole	0	0.0%		574	22.0%			0	0.0%	70	13.5%
Clozapine	0	0.0%		46	1.8%			0	0.0%	3	0.6%
Fluphenazine	69	17.5%		22	0.8%			33	22.5%	4	0.8%
Haloperidol	118	30.0%		87	3.3%			50	34.0%	36	7.0%
Olanzapine	0	0.0%		436	16.7%			0	0.0%	77	14.9%
Paliperidone	0	0.0%		57	2.2%			0	0.0%	11	2.1%
Perphenazine	0	0.0%		37	1.4%			0	0.0%	4	0.8%
Quetiapine	0	0.0%		549	21.0%			0	0.0%	145	28.0%
Risperidone	207	52.5%		802	30.7%			64	43.5%	168	32.4%

LAI, long-acting injectable antipsychotics; EPO, Exclusive Provider Organization; HMO, Health Maintenance Organization; POS, Point-of-Service; PPO, Preferred Provider Organization; POS/CP, Point-of-Service/Capitated; CDHP, Consumer Driven Health Insurance.

Table 2.  Baseline clinical characteristics of commercially and Medicare insured LAI and oral cohorts.

Variable	Commercial population				p-value	Medicare population				p-value
	LAI		Oral			LAI		Oral
Total patient count	394		2610			147		518
CCI score
Mean	0.58		0.47		0.056	1.24		1.83		0.001
SD	1.10		1.08			1.38		1.87
Median	0		0			1		1
	n	%	n	%		n	%	n	%
CCI group					0.064					0.005
0	266	67.5%	1924	73.7%		55	37.4%	150	29.0%
1–2	102	25.9%	554	21.2%		66	44.9%	211	40.7%
3–4	19	4.8%	104	4.0%		23	15.7%	108	20.9%
≥5	7	1.8%	28	1.1%		3	2.0%	49	9.5%
Condition
Myocardial infarction	4	1.0%	15	0.6%	0.304	2	1.4%	11	2.1%	0.555
Congestive heart failure	10	2.5%	55	2.1%	0.584	17	11.6%	67	12.9%	0.659
Peripheral vascular disease	9	2.3%	26	1.0%	0.026	8	5.4%	60	11.6%	0.030
Cerebrovascular disease	19	4.8%	92	3.5%	0.203	19	12.9%	127	24.5%	0.003
Dementia	7	1.8%	29	1.1%	0.258	17	11.6%	102	19.7%	0.023
Chronic pulmonary disease	48	12.2%	301	11.5%	0.707	32	21.8%	123	23.8%	0.617
Rheumatic disease	2	0.5%	31	1.2%	0.227	2	1.4%	16	3.1%	0.255
Peptic ulcer disease	2	0.5%	14	0.5%	0.942	1	0.7%	6	1.2%	0.616
Liver disease	10	2.5%	50	1.9%	0.410	6	4.1%	19	3.7%	0.816
Diabetes	59	15.0%	252	9.7%	0.001	41	27.9%	135	26.1%	0.657
Renal disease	7	1.8%	27	1.0%	0.194	6	4.1%	38	7.3%	0.161
Cancer	8	2.0%	57	2.2%	0.845	4	2.7%	47	9.1%	0.011

LAI, long-acting injectable antipsychotics; CCI, Deyo-Charlson Comorbidity Index.

Table 3.  Medication adherence, hospitalizations, and relapses of commercially and Medicare insured LAI and oral cohorts during the baseline and follow-up periods.

	LAI, mean ± SD		p-value	Oral, mean ± SD		p-value
	Baseline	Follow-up		Baseline	Follow-up
Commercially insured population
MPR	0.40 ± 0.37	0.67 ± 0.34	<0.001	0.00 ± 0.00	0.56 ± 0.35	NA
All cause hospitalizations	1.60 ± 1.66	0.70 ± 1.20	<0.001	0.82 ± 1.10	0.84 ± 1.38	0.555
Total LOS (days)	16.93 ± 20.68	6.64 ± 14.37	<0.001	6.18 ± 11.02	6.87 ± 15.50	0.061
Schizophrenia-related hospitalizations	1.03 ± 1.26	0.43 ± 0.86	<0.001	0.35 ± 0.63	0.40 ± 0.75	0.005
Total LOS (days)	12.28 ± 17.74	4.82 ± 12.80	<0.001	3.10 ± 7.13	3.70 ± 10.37	0.014
Medicare insured population
MPR	0.42 ± 0.39	0.68 ± 0.34	<0.001	0.00 ± 0.00	0.59 ± 0.36	NA
All cause hospitalizations	1.16 ± 0.97	0.52 ± 0.73	<0.001	0.94 ± 0.89	0.82 ± 1.10	0.048
Total LOS (days)	15.97 ± 19.88	6.13 ± 12.45	<0.001	8.07 ± 11.91	7.53 ± 15.59	0.528
Schizophrenia-related hospitalizations	0.82 ± 0.88	0.31 ± 0.62	<0.001	0.36 ± 0.56	0.30 ± 0.54	0.062
Total LOS (days)	11.65 ± 15.92	4.42 ± 10.80	<0.001	3.74 ± 0.56	3.20 ± 9.87	0.345

MPR, medication possession ratio; LOS, length of stay.

Figure 1.  Differences in hospitalizations (A) and length of stay (LOS) (B), all cause and schizophrenia-related between the baseline and the follow-up periods among the commercially and Medicare insured study populations.

Table 4.  Multivariate regression results for evaluation of initiating long-acting injectable antipsychotics vs oral on the differences in hospital resource usage between the baseline and follow-up periods.

Hospital usage	Difference	CI Lower	CI Upper	p-value
Commercially insured population
All cause
Hospitalization count	−0.85	−0.65	−1.05	<0.001
Length of stay (days)	−10.3	−8.0	−12.6	<0.001
Schizophrenia-related
Hospitalization count	−0.61	−0.47	−0.74	<0.001
Length of stay (days)	−7.5	−5.7	−9.3	<0.001
Medicare insured population
All cause
Hospitalization count	−0.58	−0.29	−0.86	<0.001
Length of stay (days)	−13.3	−8.9	−17.7	<0.001
Schizophrenia-related
Hospitalization count	−0.39	−0.20	−0.59	<0.001
Length of stay (days)	−8.3	−5.1	−11.6	<0.001

p-values were calculated using a generalized linear model.

CI, 95% Confidence Interval; Lower, Lower Bound; Upper, Upper Bound.