Predictors of medication nonadherence and hospitalization in Medicaid patients with bipolar I disorder given long-acting or oral antipsychotics

Figures & data

Figure 1.  Patient selection flowchart.

Table 1.  Baseline and demographic characteristics of patients with bipolar I disorder.

Characteristic	Oral first- generation only	Oral second- generation only	Oral first- and second- generation	LAI second- generation n = 221	LAI first- generation n = 413	Overall N = 9410
	n = 225	n = 7646	n = 905
Age
18–34, %	31.1	41.9	40.6	38.0	30.8	40.9
35–44, %	25.8	28.5	28.7	29.4	26.2	28.3
45–64, %	41.8	29.1	30.5	32.6	40.7	30.1
65+, %	1.3	0.6	0.2	0.0	2.4	0.6
Mean (±SD)	41.8 (12.5)	37.6 (11.8)	38.3 (11.8)	38.6 (11.7)	41.6 (12.9)	38.0 (11.9)
Median	43	37	38	40	43	38
Minimum	18	18	18	18	18	18
Maximum	73	86	67	63	80	86
IQR	32.0–51.5	28.0–46.0	29.0–47.0	30.0–48.0	32.0–50.5	28.0–47.0
Sex, %
Male	23.6	25.6	29.1	34.4	35.4	26.5
Female	76.4	74.4	70.9	65.6	64.6	73.5
Race, %
White	68.0	77.0	77.3	55.2	52.5	75.3
Black	21.8	15.9	15.8	31.7	39.7	17.4
Other	10.2	7.1	6.9	13.1	7.7	7.3
Use of selected concomitant medications, %
Antidepressants	61.3	78.0	77.8	65.2	58.6	76.4
Anxiolytics	48.0	53.6	59.7	38.0	39.0	53.0
Mood stabilizers	20.4	14.1	17.5	16.3	16.2	14.7
Anticholinergics	43.6	17.2	33.7	42.5	51.6	21.5
Anticonvulsants	57.3	63.0	67.8	67.0	58.8	63.2
Mood stabilizers or anticonvulsants	69.3	68.0	73.1	73.3	66.3	68.6
Concomitant diagnoses, %
Substance abuse diagnosis	22.2	30.9	32.3	34.4	29.1	30.8
Other psychoses diagnosis*	48.4	54.3	62.9	81.0	78.5	56.7
Diagnosis codes for bipolar disorder†, %
296.0 (bipolar I disorder, single manic episode)	4.9	5.3	3.9	9.0	11.1	5.5
296.1 (manic disorder, recurrent episode)	0.4	0.4	0.8	0.0	0.7	0.4
296.4 (bipolar I disorder,  recent/current manic episode)	24.0	22.8	28.6	44.8	39.0	24.6
296.5 (bipolar I disorder,  recent/current depressed episode)	32.0	40.2	47.2	33.5	28.8	40.0
296.6 (bipolar I disorder,  recent/current mixed episode)	25.3	37.5	36.8	36.2	32.7	36.9
296.7 (bipolar I disorder,  unspecified episode)	43.1	40.1	47.7	45.2	43.1	41.2
Charlson comorbidities‡, %
Chronic obstructive pulmonary disease	26.2	27.0	29.4	29.9	23.2	27.1
Diabetes mellitus	16.9	13.5	17.5	17.2	18.6	14.2
Charlson comorbidities score
Mean (±SD)	1.0 (1.8)	0.7 (1.2)	0.8 (1.3)	0.8 (1.3)	0.7 (1.1)	0.7 (1.2)
Median	0	0	0	0	0	0
Minimum	0	0	0	0	0	0
Maximum	9	15	13	8	8	15
IQR	0–1	0–1	0–1	0–1	0–1	0–1
New starts§, %
Yes	33.3	42.2	33.4	20.4	18.2	39.6
No	66.7	57.8	66.6	79.6	81.8	60.4
Psychiatric-related hospitalizations  before index, %
Patients with a psychiatric-related  hospitalization	21.3	34.7	42.8	57.9	41.9	36.0

*Other psychotic conditions included ICD-9-CM diagnosis codes 290.xx–299.xx.

†Patient had at least one inpatient or two outpatient codes.

‡Only comorbidities present in at least 5% of the sample were reported.

§Defined as a patient who did not receive an antipsychotic in the first 275 days of the baseline (preindex) period but received an antipsychotic after this date and before the index date.

IQR, interquartile range; LAI, long-acting injectable; SD, standard deviation.

Table 2.  Medication adherence in the follow-up period in patients with bipolar I disorder.

Characteristic	Oral first- generation only	Oral second- generation only	Oral first- and second-generation	LAI second- generation	LAI first- generation	Overall N = 9410
	n = 225	n = 7646	n = 905	n = 221	n = 413
MPR
MPR 0.8–1, %	42.7	38.9	46.3	52.9	51.6	40.6
MPR 0.5–<0.8, %	16.0	25.2	22.3	29.9	23.5	24.7
MPR <0.5, %	41.3	35.9	31.4	17.2	24.9	34.7
Mean (±SD) MPR	0.57 (0.36)	0.63 (0.29)	0.66 (0.30)	0.74 (0.24)	0.70 (0.29)	0.63 (0.29)
Median MPR	1	1	1	1	1	1
Minimum MPR	0	0	0	0	0	0
Maximum MPR	1	1	1	1	1	1
IQR	0.17–0.91	0.36–0.90	0.40–0.93	0.59–0.95	0.50–0.95	0.37–0.91
Persistence
Mean (±SD)	0.79 (0.31)	0.84 (0.26)	0.90 (0.19)	0.94 (0.17)	0.93 (0.17)	0.85 (0.25)
Median	1	1	1	1	1	1
Minimum	0	0	0	0	0	0
Maximum	1	1	1	1	1	1
IQR	0.64–1.00	0.75–1.00	0.89–1.00	0.99–1.00	0.96–1.00	0.79–1.00
Maximum gaps in treatment
Mean (±SD)	51.5 (68.4)	49.3 (60.9)	58.7 (71.9)	42.6 (52.1)	46.8 (60.4)	50.0 (62.1)
Median	25	26	28	22	21	26
Minimum	0	0	0	0	0	0
Maximum	350	350	354	282	329	354
IQR	8–67	9–64	9–83	8–57	8–64	9–66

IQR, interquartile range; LAI, long-acting injectable; MPR, medication possession ratio; SD, standard deviation.

Figure 2.  Adjusted odds of medication nonadherence among patients with bipolar I disorder treated with antipsychotic medications^a. LAI, long-acting injectable; OR, odds ratio; CI, confidence interval; MPR, medication possession ratio.

Table 3.  Percentage of hospitalizations and emergency room visits in the follow-up period in patients with bipolar I disorder.

Characteristic, %	Oral first- generation only	Oral second- generation only	Oral first- and second- generation	LAI second- generation n = 221	LAI first- generation n = 413	Overall N = 9410
	n = 225	n = 7646	n = 905
All-cause ER visits
Patients with an ER visit	53.8	66.6	73.5	74.7	60.3	66.9
Patients with MPR ≥0.8 with an ER visit	38.5	57.4	61.1	70.9	51.6	57.4
Patients with MPR <0.8 with an ER visit	65.1	72.5	84.2	78.8	69.5	73.3
Patients with 1 ER visit	4.0	5.8	5.1	5.9	4.4	5.6
Patients with 2 ER visits	7.6	10.7	9.4	13.6	8.5	10.5
Patients with 3 or more ER visits	42.2	50.1	59.0	55.2	47.5	50.8
Psychiatric-related ER visits
Patients with a psychiatric-related ER visit	19.1	27.5	39.3	46.6	37.5	29.3
Patients with MPR ≥0.8 with a  psychiatric-related ER visit	10.4	23.5	30.5	46.2	32.9	25.2
Patients with MPR <0.8 with a  psychiatric-related ER visit	25.6	30.0	46.9	47.1	42.5	32.1
Patients with 1 psychiatric-related ER visit	7.1	10.5	11.0	12.2	8.7	10.4
Patients with 2 psychiatric-related ER visits	4.4	7.5	10.1	11.8	8.2	7.8
Patients with 3 or more psychiatric-related ER visits	7.6	9.5	18.2	22.6	20.6	11.1
All-cause hospitalization
Patients with any hospitalization	31.6	36.8	55.2	67.0	54.2	39.9
Patients with MPR ≥0.8 with any hospitalization	15.6	33.5	52.7	61.5	50.7	36.9
Patients with MPR <0.8 with any hospitalization	43.4	38.8	57.4	73.1	58.0	41.9
Patients with 1 hospitalization	17.8	19.7	22.7	26.2	21.8	20.2
Patients with 2 hospitalizations	4.9	8.4	11.9	13.1	13.8	9.0
Patients with 3 or more hospitalizations	8.9	8.6	20.7	27.6	18.6	10.7
Psychiatric-related hospitalizations
Patients with a psychiatric-related hospitalization	28.0	33.7	51.4	65.2	52.3	36.8
Patients with MPR ≥0.8 with a  psychiatric-related hospitalization	14.6	30.9	50.6	59.8	48.4	34.5
Patients with MPR <0.8 with a  psychiatric-related hospitalization	38.0	35.5	52.1	71.2	56.5	38.4
Patients with 1 psychiatric-related hospitalization	15.6	18.9	20.9	25.3	23.0	19.3
Patients with 2 psychiatric-related hospitalizations	5.8	7.7	12.2	12.7	11.4	8.3
Patients with 3 or more  psychiatric-related hospitalizations	6.7	7.2	18.3	27.1	17.9	9.2

ER, emergency room; LAI, long-acting injectable; MPR, medication possession ratio.

Figure 3.  Adjusted odds of all-cause hospitalization among patients with bipolar I disorder treated with antipsychotic medications. OR, odds ratio; CI, confidence interval; MPR, medication possession ratio.

Figure 4.  Adjusted odds of psychiatric-related hospitalization among patients with bipolar I disorder treated with antipsychotic medications. OR, odds ratio; CI, confidence interval; MPR, medication possession ratio.