Table 5.

An alternative measure of treatment persistence, by treatment episodes, period, and definition of treatment discontinuation

	Period 1 (10/1/1999–3/31/2002)				Period 2 (10/1/2002–3/31/2005)
	Gap ≥15 days as treatment discontinuation				Gap ≥15 days as treatment discontinuation
	All episodes	Episode-specific			All episodes	Episode-specific
Drug class		1 episode	2 episodes	3 episodes		1 episode	2 episodes	3 episodes
	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
Atypical agents	187 ± 153	179 ± 142	212 ± 187	217 ± 190	171 ± 150	\ ± 139	199 ± 181	222 ± 190
Typical agents	137 ± 135	125 ± 127	167 ± 158	180 ± 152	141 ± 136	127 ± 124	177 ± 169	197 ± 183
	Gap ≥30 days as treatment discontinuation				Gap ≥30 days as treatment discontinuation
	All episodes	Episode-specific			All episodes	Episode-specific
Drug class		1 episode	2 episodes	3 episodes		1 episode	2 episodes	3 episodes
	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
Atypical agents	201 ± 146	197 ± 143	219 ± 154	215 ± 184	180 ± 148	174 ± 141	206 ± 183	212 ± 176
Typical agents	147 ± 139	139 ± 133	175 ± 165	184 ± 153	151 ± 140	141 ± 130	194 ± 188	171 ± 139

T-tests of means indicate that all differences between typical and atypical agents are statistically significant at p < 0.001.