Treatment Adherence in Schizophrenia: Which Antipsychotic Is Best?

Table 1 – Treatment Outcomes¹

Medication Adherence and Persistence		Treatment Patterns
• Adherence – proportion of days covered (PDC) ≥80% o PDC = quantity of non-overlapping days of supply divided by 365 days • Persistence – determined by the percent patients without a continuous gap of ≥30, 60, or 90 days between days of supply		• Number of prescription fills of AP • Other psychiatric medication use (i.e. anxiolytics, mood stabilizers, antidepressants) • AP polypharmacy presence (≥2 AP agents used for ≥60 consecutive days with a gap of <7 days) • Psychiatric polypharmacy presence (≥1 AP medication and ≥1 anxiolytic, antidepressant, or mood stabilizer used for ≥60 consecutive days with a gap of <7 days)

Table 2 – Adherence and Persistence Results¹

Outcome	Measure	FGA-LAI vs OAP	SGA-LAI vs OAP
Adherence	PDC ≥80% Related Content	15.8% vs 24.6% (P< 0.001)	27.2% vs 24.6% (P=0.008)
Adherence	PDC for the index medication	45.2% vs 44.1% (P=0.160)	49.3% vs 44.1% (P=0.007)
Persistence	No gap ≥30 days	13.6% vs 20.6% (P<0.001)	23.7% vs 20.6% (P<0.001)
	No gap ≥60 days	30.6% vs 30.2% (p-value not reported)	37.1% vs 30.2% P=0.001)
	No gap ≥90 days	41.2% vs 36.9% (P <0.004)	42.9% vs 36.9% (P <0.001)

Table 3 – Adjusted Adherence and Persistence Results¹

Outcome	Measure	FGA-LAI vs OAP	SGA-LAI vs OAP
Adherence	PDC ≥80%	OR 0.52; 95% CI: 0.43, 0.61; (P<0.001)	OR 1.24; 95% CI: 1.11, 1.38; (P<0.001)
Persistence	No gap ≥30 days	OR: 0.55; 95% CI: 0.46, 0.67; (P<0.001)	OR: 1.31; 95% CI: 1.17, 1.47; (P<0.001)
	No gap ≥60 days	OR: 0.95; 95% CI: 0.83, 1.10; (P=0.501)	OR 1.46; 95% CI: 1.32, 1.62; (P<0.001)
	No gap ≥90 days	OR: 1.13; 95% CI: 0.99, 1.29; (P=0.071)	OR: 1.35; 95% CI:1.23, 1.49; (P<0.001)

Abbreviations: CI – Confidence Interval; OR – Odds Ratio

Table 4 – Limitations of the Study¹

• Data may not represent generalized population
o Obtained from Medicaid patients in 6 states

• Data utilized in the study subject to inaccuracies, confounders etc.

• Adherence measures (i.e. PDC) difficult to assess
o Unknown whether drug dispensed was administered as prescribed

• Pharmacokinetic profiles of LAI and OAP medications not accounted for

• Intent-to-treat method did not account for interchanging or discontinuing treatment

• Majority of OAP group were receiving SGA-OAP (78%)

References

1. Pilon D, Joshi K, Tandon N, et al. Treatment patterns in Medicaid patients with schizophrenia initiated on a first- or second-generation long-acting injectable versus oral antipsychotic. Patient Preference and Adherence. 2017; 11: 619-629.

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