SEATTLE – The relative efficacy of three treatments for anorexia nervosa appears to shift with long-term follow-up according to the results of an ongoing analysis of data from a randomized, controlled trial.
The treatment that was the most efficacious at the end of therapy appeared to be the least so at 5 years. But differences among the therapies were much less significant at that point, Virginia V.W. McIntosh, Ph.D., reported at an international conference sponsored by the Academy for Eating Disorders.
Dr. McIntosh, a senior clinical psychologist at the University of Otago, Christchurch, New Zealand, described ongoing analyses of data from a randomized, controlled trial that compared three treatments–cognitive-behavioral therapy (CBT), interpersonal psychotherapy (IPT), and specialist supportive clinical management (SSCM)–among 56 patients with anorexia nervosa.
End-of-treatment results showed that among the 35 patients who completed all sessions, SSCM was superior to both CBT and IPT in terms of global anorexia nervosa status (Am. J. Psychiatry 2005;162:741–7).
One of the new analyses focused on therapist adherence to the protocol for a specific treatment.
Dr. McIntosh and her colleagues measured adherence with a modified version of the Collaborative Study Psychotherapy Rating Scale, which had 28 items unique to IPT, 27 unique to CBT, and 3 unique to SSCM. “I think [adherence] speaks to the distinctiveness of CBT and SSCM, which is important here,” Dr. McIntosh said at the meeting, which was cosponsored by the University of New Mexico.
An additional 14 items overlapped both CBT and SSCM. Those overlap items were items that covered the important elements of weight gain, psychoeducation, and the normalization of eating, she said. An additional 18 items were not specific to any of the therapies and reflected aspects such as alliance and therapy process.
Independent raters listened to the recorded psychotherapy sessions from the trial and rated them for adherence on various subscales: CBT (unique plus overlapping items), CBT-only (unique items), IPT, SSCM (unique plus overlapping items), and a therapy-nonspecific subscale.
Results showed that ratings for the therapy-specific subscales did indeed differ significantly, depending on which therapy the patient had received during a session, Dr. McIntosh reported. Ratings were highest for the corresponding therapy in all cases. For example, the CBT subscale scores were highest for CBT sessions.
In contrast, ratings for the therapy-nonspecific subscale did not differ depending on which therapy the patient had received.
Another new, ongoing analysis of the trial data focused on long-term outcomes. Data at 5 years were available for 45 patients (80% of those initially randomized), Dr. McIntosh said. “The differences at 5 years are much less than the differences at end of treatment,” she reported.
“What we see is that the SSCM group has lost some ground in terms of the proportion with a good outcome, CBT has gained some ground at about the same rate at which SSCM has lost ground, and IPT has gained even more ground,” she said.
As a result, the proportion of patients with a good outcome at the 5-year time point was highest for IPT, intermediate for CBT, and lowest for SSCM.
The trial is comparing CBT, IPT, and SSCM among 56 patients with anorexia nervosa. DR. MCINTOSH