Maintenance of response with atypical antipsychotics in the treatment of schizophrenia: a post-hoc analysis of 5 double-blind, randomized clinical trials

Table 2 Proportion of patients shown by treatment group who lost response after Week 8*.

Study	Treatment	Patients who Lost Response, % (n/N)	p value^a	NNT (95% CI)^b
Tran [13]	Olanzapine	11.4% (12/105)	.002
	Risperidone	28.7% (27/94)		6 (4, 16)
Kinon [14]	Olanzapine	9.6% (5/52)	.01
	Quetiapine	31.1% (14/45)		5 (3, 18)
Breier [17]	Olanzapine	16.9% (28/166)	.02
	Ziprasidone	29.3% (36/123)		9 (5, 40)
Kinon [16]	Olanzapine	4.9% (3/61)	.02
	Ziprasidone	20.4% (10/49)		7 (4, 34)
Kane [15]	Olanzapine	13.1% (20/153)	.999
	Aripiprazole	12.5% (17/136)		-175 (-13, 15)

Abbreviations: PANSS = Positive and Negative Syndrome Scale; CGI-S = Clinical Global Impression Severity Index; n = number of patients who lost response after Week 8; N = number of patients who had response at Week 8; NNT = number needed to treat; CI = confidence interval.
^a Fisher's exact test.
^b NNT = 1/Absolute Risk Reduction, with 95% CI calculated as previously described [22].
* Proportion of patients who lost response (≥ 20% worsening of PANSS Total score and CGI-S score ≥ 3 occurring any time after Week 8) after having achieved response (≥ 20% improvement over baseline PANSS Total score at Week 8) for 5 randomized, double-blind studies of olanzapine versus another atypical comparator. Also shown are the numbers needed to treat (NNT) with olanzapine rather than comparator to avoid loss of one additional responder.

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