PMH7 - Finding Early Improvement Threshold to Predict Response After 8 Weeks of Treatment Using Olanzapine in First-Episode Schizophrenia

Abstract

Presently, schizophrenia guidelines recommend waiting for 8 weeks before considering a patient as non-responder. This study aims to assess whether the early response (week 2,3 and 4) can predict the outcome at 8th week for the treatment of first episode schizophrenia (FES) using olanzapine. A prospective observational study was conducted in 36 adult FES patients with four points follow up (week 2,3,4 and 8). Patients with any other psychiatric co-morbidities and/or taking any antipsychotics were excluded from the study. A reduction of 25% in PANNS score from the base line at week 3 and 30% at week 4 were considered as early response. A reduction of 50% at week 8 was considered as responders. Receiver Operating Characteristics (ROC) curves were implemented to detect the optimal threshold of early response (AUC>80%) at 2nd, 3rd and 4th weeks. To identify the variables that are predictive of treatment responses at Week 8, binary logistic regression was performed. The mean total PANSS baseline score of the study population was 106.66 (95% C.I, 100.4-112.9). Week 2 (AUC=50.5, P=0.964) and week 3 (AUC=64.9, P=0.136) responses failed to predict the 8th week response. Week 4 response (AUC = 92%, P<0.001) can be taken for the prediction of 8th week response (specificity=72%, sensitivity=100%, Positive Predictive Value=61.1%, Negative Predictive Value=100% and OER was <29.4% reduction). 25 patients (69%) achieved more than 50% reduction (responders) in PANSS score after 8 weeks of treatment. Independent predictors for good treatment responses at Week 8 were female gender (P=0.032), a higher educational level(P=0.021) and non-smoking(P=0.014) and non-alcoholics (P=0.048). Our study suggests that patients with early response at week 4 are likely to achieve positive response after 8 weeks. This may help in appropriate clinical decision making for early non-responders.