Elsevier

Psychiatry Research

Volume 209, Issue 3, 30 October 2013, Pages 401-405
Psychiatry Research

Short-term remission in schizophrenia as a combination of several outcome measures

https://doi.org/10.1016/j.psychres.2013.04.009Get rights and content

Abstract

Clinical, cognitive, metabolic and functioning variables have been evaluated in patients with schizophrenia in an 8-week trial with Ziprasidone. The aim of this post-hoc analysis is to investigate how these variables interact in determining short-term remission. Baseline values or the variation from baseline to endpoint were considered predictors. 262 schizophrenic patients were recruited. Two logistic regressions were conducted to determine which variables predict remission. The first was performed on baseline values as predictors. The second used the variation from baseline to endpoint (delta) of the outcome evaluations as predictors. Using literature reported criteria for remission, we distinguished 124 subjects (47.33%) in remission, and 138 not in remission at the end of the trial. The first logistic regression does not show a good fit. The second logistic regression, with delta scores as predictors, reports instead an overall good fit (71.8% of the predicted cases assigned to the right category). The analysis reveals that general score from Positive and Negative Syndrome Scale (PANSS), cholesterol LDL, subjective well-being under neuroleptic, Simpson–Angus Scale (SAS) delta scores, drug dosage and premorbid intelligence entered in the equation. These results suggest that indexes such as cognition, metabolic status, other than symptoms, have to be taken into account in order to refine the short-term remission prediction.

Introduction

The issues of remission and recovery in schizophrenia have received increasing attention in the last decade, offering new opportunities for clinical practice, health services research and clinical trials (Andreasen et al., 2005, van Os et al., 2006, Davidson et al., 2008, Rossi et al., 2009).

Pharmacotherapy for schizophrenia and related disorders is well established in clinical psychiatry and offers considerable benefit in controlling symptoms and preventing relapse (Lehman et al., 2004). Short-term efficacy and relapse-prevention studies have the value of establishing a quantitative aspect of pharmacotherapy related mainly to efficacy and safety (Kane et al., 2003, Honer et al., 2007).

In a previous study, Rossi et al. (2008) reported the results of an investigation on a total of 312 patients with schizophrenic disorder who were switched to an 8-week, open-label, flexible dose (40–160 mg/day) of Ziprasidone. Significant improvements from baseline to endpoint were reported for Positive and Negative Syndrome Scale scores, Clinical Global Impression Severity, Global Assessment of Functioning, Well-being under Neuroleptic scores, and Trail Making Test. Significant improvements were also found for mean Simpson–Angus scale score, sexual dysfunction, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. In addition, mean bodyweight significantly decreased from baseline.

It is arguable that several variables, other than symptom assessment, could play a role in drug response and remission achievement (Davidson et al., 2008, Lambert et al., 2010, Clark et al., 2011, Oorschot et al., 2012).

In the current study we performed a post-hoc analysis, re-examining previous data in order to look at how these variables interact in determining short-term remission. With this aim we utilized the severity criteria of the original remission definition by Andreasen et al. (2005), omitting the temporal requirement because the 8-week study is too short to discern longer-term out-comes.

We planned a logistic stepwise regression model to explore how different kinds of variables (i.e. socio-demographic, cognitive functioning, laboratory metabolic and clinical parameters) could explain symptom remission (Gharabawi et al., 2006). The considered independent variables were not only baseline values of these variables but the variations from baseline to endpoint were also included in order to investigate how the modification during a trial could be associated with short-term remission as the primary outcome.

Section snippets

Subjects

The study group included 262 outpatients aged 18–60 years [155 men and 107 women; age (mean±S.D.) 38.19±9.66; age at onset 27.47±8.02] with diagnosed schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This sample was drawn from that enrolled in the Rossi et al. (2008) study including 312 patients, of whom 238 completed the 8-week trial. Twenty-four more patients who completed at least 6 weeks of treatment, and who attended the trial for an adequate

Results

The non-remission/remission state criteria divided the total sample into a group of 138 subjects not in remission at the end of the trial and 124 in a state of remission.

The first stepwise logistic regression reveals that the only significant predictors of the remission state are three variables: GAF, Negative and Positive PANSS basal scores that entered in the final equation, with the highest significance for GAF (Table 1). The classification table of observed vs. predicted cases shows the

Discussion

The basic idea was to explore variables other than symptoms possibly related to short-term remission in an 8-week Ziprasidone trial in schizophrenia.

The first logistic analysis reveals unsurprising results: the baseline variables that were entered in the model are related to symptomatology, i.e. negative and positive symptoms, and global functionality. This kind of approach can be considered quite naïve, because it is substantially affected by illness severity and functional status, defining

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    The authors report no financial relationships with commercial interests.

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