These analyses reveal that in this adolescent ED population, 62.4% are properly diagnosed with EDNOS, if strictly applying current DSM-IV standards. However, 61.6% of these EDNOS patients meet recommended criteria for medical hospitalization, and are more compromised than BN patients in most medical outcomes. Despite their younger age, they displayed similar disease duration and rates of weight loss, QTc prolongation, orthostasis, and hypokalemia as their full diagnostic counterparts. This is despite the fact that they weighed significantly more than patients with AN. These results do not support our initial hypothesis that EDNOS would be less medically severe than AN or BN.
We proposed new groupings of pAN and pBN patients within the EDNOS group, with each subgroup directly challenging one DSM-IV criterion for AN or BN. When pAN patients were compared to those with AN, there were few differences. pAN patients as a whole were less likely to have a low heart rate or blood pressure, but did not differ from AN patients on most other medical outcomes. Adolescents with pAN were younger and weighed significantly more, but had lost weight more rapidly than those with AN and had a shorter disease duration.
Of pAN subgroups, those EDNOS patients who had lost over 25% of their pre-morbid body weight (pAN-25) appeared more compromised than other subgroups of pAN, and even more than AN patients in some medical outcomes. This is the case despite being at a significantly higher, near “ideal” body weight, reminding us that malnutrition is a complex disease with manifestations at multiple weights. In addition, another pAN subgroup, those not meeting menstrual criteria (pAN-NM), was older, possibly indicating later recognition of the ED.
Patients with pBN were younger, had a shorter duration of disease, weighed less and had lost weight more rapidly than their BN counterparts. However, pBN patients and subgroups did not differ significantly from BN adolescents on most other medical outcomes examined.
When pAN was compared to pBN, pAN patients were more medically severe, with the exception of duration of illness and the QTc interval, where pBN patients had more months of disease and longer QTc intervals. This mirrors our comparison of BN to AN, where BN patients report nearly twice the duration of disease and longer mean QTc intervals. Patients with pAN and pBN were similar only in rates of hypokalemia, hypophosphatemia, and orthostasis. This lends credence to the idea that EDNOS is too heterogeneous a category, as patients diagnosed differ more from each other than they do from AN and BN, respectively. EDNOS patients who narrowly miss criteria for AN and BN are often medically compromised and in need of treatment.
To our knowledge, this is the first published comparison of reported complications among ED adolescents from all DSM-IV diagnostic groups. While AN patients certainly had a high rate of objective medical complications observed during their first hospital stays, the complication profiles of other patients was hardly reassuring. Partial AN and pBN patients also displayed high rates of hospital complications at around 18% and 19% respectively, and BN and pBN patients reported significantly higher numbers of serious complications prior to presentation than their AN and pAN peers. While further prospective study is required to confirm these findings, they imply the need to better delineate predictors of complications and medical protocols in each DSM group separately, rather than measuring each group against an AN standard.
Limitations of this study include that it is a clinical sample from a subspecialty ED program, which limits its generalizability. It is also an exclusively female sample, and while it is critical that we better learn how to manage adolescent males with EDs, this study does not inform that pursuit. Data were collected retrospectively, and thus data may be missing for non-random reasons not yet identified. In addition, clinical decisions had been made which influenced the choice of laboratory tests, which may have introduced bias based on medical severity. In general, most variables were missing fewer than 10% of data, but phosphorus levels, electrocardiograms, and orthostatic testing were missing in 10–20% of subjects, thereby necessitating caution in the interpretation of these variables.
A limitation of any study of current medical hospitalization criteria for ED patients is that they were derived from expert consensus and not from longitudinal study. Bradycardia, hypotension, orthostasis, and hypothermia have clearly been shown in studies to be strong indicators of a malnourished state, and have therefore been adopted as indicators of medical severity in patients with EDs.[31
] In addition, QTc prolongation has been shown to be a risk factor for sudden cardiac death,[36
] which makes it the most concerning complication of the ones examined here. However, we do not have evidence that these findings mandate hospitalization, nor are we certain that hospitalization improves long-term medical outcomes. It is possible that in the future outpatient treatment regimens may prove to be equally effective and safe in treating these cardiac sequelae, and further prospective study is urgently needed to delineate the most appropriate type of interventions, and when they are indicated.
These analyses reveal that there exist adolescent ED patients within a larger EDNOS group who are medically similar to AN and BN patients. They provide a rationale to consider changes to the diagnostic criteria for adolescents with ED, as other authors have recently proposed.[3
] For example, cut-points of weights, duration of behaviors and endocrine dysfunction are not currently evidence-based and thus may not be truly reflective of medical severity.[47
] Our study also suggests that current criteria for medical intervention may be most appropriate for adolescents with AN, but that we may miss critical opportunities for intervention and prevention in other ED groups.
Finally, our data propose another possibility of diagnostic groupings, which are shown in , illustrating the original percentage of patients in AN, BN, and EDNOS categories, and comparing that with a new grouping where pAN and pBN are counted as a subgroup of AN and BN, respectively. If patients with pAN and pBN are combined into AN and BN groups, only 14.3% of patients with “true” EDNOS remain, similar to another recent diagnostic reclassification of adult ED patients.[38
] If over 60% of patients have EDNOS by DSM-IV criteria, they are effectively forced into diagnostic categories lacking definition, health care coverage, or medical knowledge. In adolescents and children especially, eating disorders are a devastating set of diseases with multiple long-term sequelae. It is clear that a diagnosis of EDNOS does not imply a reassuring medical profile, and these findings underscore the need to intervene early, even when young patients do not meet full diagnostic criteria for AN or BN. Future studies should be directed toward better defining the best clinical criteria by which we can intervene both medically and psychiatrically in these diverse set of illnesses.
DSM-IV and Proposed Diagnostic Categories