Rates and predictors of antipsychotic non-adherence and hospitalization in Medicaid and commercially-insured patients with schizophrenia

Figures & data

Figure 1. Sample patient timeline.

Figure 2. Flowchart of sample selection.

Table 1. Baseline characteristics, antipsychotic adherence, and hospitalizations among patients with schizophrenia.

	Medicaid	Commercial
Characteristic	(n = 20,710)	(n = 7528)
Age
Mean (±SD)	42.6 (14.1)	47.9 (17.1)
Median	45	50
IQR	31.0–53.0	36.0–59.0
Male, %	46.9	46.5
Race, %
White	42.7	N/A
Black	47.4
Other	8.7
Unknown	1.2
Use of selected concomitant medications, %
Antidepressants	55.2	53.0
Anxiolytics	35.6	34.3
Mood stabilizers	6.3	8.7
Anticholinergics	35.7	20.5
Anticonvulsants	44.3	38.0
Concomitant diagnoses, %
Substance abuse diagnosis	15.7	10.0
Other psychoses diagnosis^a	46.9	54.0
Selected comorbidities, %
Chronic pulmonary disease	20.0	15.7
Diabetes without complications	18.4	18.1
Diabetes with chronic complications	5.2	1.8
Cerebrovascular disease	3.6	5.5
Congestive heart failure	3.6	3.7
CCI score, mean (SD)	0.8 (1.4)	0.7 (1.3)
Patients with a baseline antipsychotic, n (%)	18,106 (87.4%)	5708 (75.8%)
Days of any treatment during baseline^b
Mean (±SD)	266.8 (96.8)	246.7 (99.6)
Median	309	278
IQR	211–341	180–328
New starts^c
Yes	13.8%	26.5%
No	86.2%	73.5%
MPR^d
Percentage with MPR < 0.80	34.1%	37.5%
Mean (±SD) MPR	0.80 (0.24)	0.78 (0.24)
Median MPR	0.90	1.00
IQR	0.69–0.97	0.66–0.96
Psychiatric-related hospitalizations^e
Percentage of patients with a  psychiatric-related hospitalization	27.7%	29.0%
Mean (±SD) number of  psychiatric-related hospitalizations	0.55 (1.36)	0.49 (1.04)
Median	0	0
IQR	0–1	0–1

CCI, Charlson Comorbidity Index; IQR, interquartile range; MPR, medication possession ratio; SD, standard deviation.

Source: Thomson Reuters MarketScan Multi-State Medicaid Claims Database 2007–2010 and IMS LifeLink Health Plan Claims Database 2007–2010.

^aOther psychotic conditions included ICD-9-CM diagnosis codes 290.xx–299.xx, excluding 295.xx.

^bOnly includes claims for antipsychotics that occurred in the 12 months before index. Patients may have had a previous supply of medication at the start of baseline, which was not captured in this analysis.

^c‘New start’ is defined as a patient who did not receive any antipsychotic in the first 275 days of the baseline (pre-index) period but who received a medication after this date or starting on the index date.

^dMPR is defined as the number of days (ambulatory days) the patient received antipsychotic divided by the number of days (ambulatory days) remaining in the period (i.e., from start to end of data) after the first antipsychotic was dispensed.

^ePsychiatric-related hospitalizations were identified by any diagnosis of ICD-9-CM codes 290.xx–319.xx.

Table 2. Antipsychotic adherence and concomitant psychiatric medications in the 12 months following index among patients with schizophrenia.

	Medicaid	Commercial
Characteristic	(n = 20,710)	(n = 7528)
Type of antipsychotic(s) received, n (%)
Oral atypical only	12,395 (59.9)	5323 (70.7)
Injectable conventional	3342 (16.1)	288 (3.8)
Oral conventional and oral atypical	2288 (11.0)	926 (12.3)
Injectable atypical	1806 (8.7)	251 (3.3)
Oral conventional only	879 (4.2%)	740 (9.8%)
MPR^a
Percentage with MPR < 0.80	37.5	44.6
Mean (±SD)	0.77 (0.25)	0.73 (0.27)
Median	0.89	0.84
IQR	0.64–0.97	0.54–0.95
Persistence^b
Mean (±SD)	0.94 (0.17)	0.90 (0.21)
Median	1.00	1.00
IQR	0.99–1.00	0.95–1.00
Maximum gap in treatment, days
Mean (±SD)	35.2 (50.5)	38.8 (53.8)
Median	14.0	18.0
IQR	5–43	6–46
Use of selected concomitant medications, %
Antidepressants	59.6	60.0
Anxiolytics	39.6	39.1
Mood stabilizers	6.6	10.7
Anticholinergic agents	40.5	27.3
Anticonvulsants	48.5	45.2
Mood stabilizers or anticonvulsants	51.0	49.5
Concomitant diagnoses, %
Substance abuse diagnosis	15.9	8.3
Other psychoses diagnosis^c	47.4	52.2

IQR, interquartile range; MPR, medication possession ratio; SD, standard deviation.

Source: Thomson Reuters MarketScan Multi-State Medicaid Claims Database 2007–2010 and IMS LifeLink Health Plan Claims Database 2007–2010.

^aMPR is defined as the number of days (ambulatory days) the patient received antipsychotic divided by the number of days (ambulatory days) remaining in the period (i.e., from start to end of data) after the first antipsychotic was dispensed.

^bPersistence is defined as the number of days between the first and last day receiving an antipsychotic divided by the number of days remaining in the period after the first antipsychotic was dispensed.

^cOther psychotic conditions included ICD-9-CM diagnosis codes 290.xx–299.xx, excluding 295.xx.

Figure 3. Predictors of future antipsychotic non-adherence among patients with schizophrenia treated with antipsychotics (adjusted odds ratios) (A) Medicaid population, (B) Commercial population. Note: * indicates significance at P < 0.05.

Figure 4. Predictors of psychiatric hospitalization among patients with schizophrenia treated with antipsychotics (adjusted odds ratios) (A) Medicaid population, (B) Commercial population. Note: Follow-up MPR is for antipsychotics; * indicates significance at P < 0.05.

Figure 5. Predictors of all-cause hospitalization among patients with schizophrenia treated with antipsychotics (adjusted odds ratios) (A) Medicaid population, (B) Commercial population. Note: Follow-up MPR is for antipsychotics; * indicates significance at P < 0.05.