Of particular interest are the patients who gained more than 7% of their initial body weight. Of the 61 patients who did so in CATIE phase 1, 42% of those randomized to ziprasidone(Drug information on ziprasidone) in phase 2T lost over 7% of their body weight, compared with 20% for risperidone(Drug information on risperidone), 7% for quetiapine(Drug information on quetiapine), and 0% for olanzapine(Drug information on olanzapine). This translates to number needed to treat comparing ziprasidone with risperidone (5), quetiapine (3), and olanzapine (3). For every 3 patients who gained more than 7% of their baseline weight in phase 1 and who were subsequently randomized to ziprasidone in phase 2 instead of olanzapine or quetiapine, an additional case of weight loss greater than 7% was observed.
CASE VIGNETTE cont’d
Simone was given ziprasidone with some concerns on her part because she had never taken it before and was unsure whether it would work for her. She was also concerned about the need to change her schedule to take ziprasidone with a meal.11 However, she was interested to see if her weight would be better controlled.
Ongoing monitoring of weight continues to be necessary and amenability to a weight reduction program needs to be assessed. Monitoring weight at each patient visit allows the clinician to catch a problem early, before substantial weight gain has set in. It also underscores to both the patient and the clinician the importance of physical fitness. Weight management strategies include both psychoeducational and medication interventions; the latter technique is less successful than the former.12
CASE VIGNETTE cont’d
Simone is not particularly worried about rehospitalization—her symptoms were successfully managed throughout the crisis by increasing her attendance at her day treatment program from 3 times a week to every day. Her sister, Sabella, however, has had a stormier course, with rehospitalizations occurring almost every 6 months. Both Simone and Sabella are worried about their weight. Can we quantify trade-offs between avoidance of hospitalization versus weight gain?
The CATIE study informs us about balancing the risk of weight gain versus the risk of hospitalization caused by exacerbation of schizophrenia. In phase 1, the numbers needed to treat to avoid hospitalization for exacerbation of schizophrenia based on 1-year risk ratios (hospitalizations per total person-years of exposure) are listed in Table 7.13
Although olanzapine had advantages regarding avoidance of hospitalization, it was associated with higher rates of weight gain in excess of 7% of baseline. Pairwise comparisons can be made and number needed to harm for weight gain can be calculated. Number needed to harm is an analogue of number needed to treat and is used when referring to undesirable outcomes. It is calculated the same way as number needed to treat. Table 8 provides the number needed to harm for weight gain.