Reviewing CATIE for clinicians: balancing benefit and risk using evidence-based medicine tools

In order to learn from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia study and apply its results to day-to-day clinical practice, it would be useful to quantify the benefits and risks of the studied antipsychotics.

Reviewing the CATIE results from the perspective of evidence-based medicine metrics of attributable risk (AR), number needed to treat (NNT), number needed to harm (NNH), and likelihood of being helped or harmed (LHH) helps clinicians translate the CATIE findings for individualized treatment in clinical practice.

Use of these evidence-based tools demonstrates that the NNT to avoid a psychiatric hospitalization due to the exacerbation of schizophrenia ranged from 3 to 7 in favor of olanzapine compared with the other antipsychotics. The NNH to produce one treatment-emergent adverse event of weight gain > 7% ranged from -5 to -8 (favoring comparators over olanzapine). Further, when assessing LHH - the likelihood of being helped (avoid a psychiatric hospital admission) compared to the likelihood of being harmed (experience weight gain > 7%) - treatment with olanzapine was consistently associated with greater expectation of benefit than harm (LHH > 1).

The use of NNT, NNH, and LHH can be helpful in balancing risk versus benefit in selecting antipsychotic treatment.

NNT and NNH may vary with baseline risk, and cannot be calculated from continuous variables. LHH may be influenced by an individual's perception of the value of the outcomes compared.