Smith et al developed a model for identifying a patient who is potentially somatizing. This can help to identify a patient who may benefit from an evaluation for somatization behavior. The authors are from Michigan State University in East Lansing.
Parameters:
(1) gender
(2) number of visits per year
(3) percent of visits with a diagnosis indicating somatization potential (presumably from 0 to 100)
|
Parameter
|
Finding
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Points
|
|
gender
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male
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0
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|
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female
|
1
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Somatization potential was based on the presence of certain ICD-9 codes:
(1) 320 to 389 (nervous system and sense organs)
(2) 570 to 579 (digestive system)
(3) 710 to 739 (musculoskeletal and connective tissue)
(4) 780 to 799 (symptoms, signs and ill-defined conditions)
percent of visits =
= (number of visits with somatic potential diagnosis) / (total number of visits) * 100
X =
= (1.146 * (points for gender)) + (0.166 * (number of visits)) + (0.057 * (points for somatic potential)) – 7.420
probability of somatization =
= 1 / (1 + EXP((-1) * X))
Interpretation:
• A person was predicted to be a somatizer if the probability was >= 0.40.
Performance:
• The prevalence of somatization in high use patients was 14%
• Using a cutoff of >= 0.40 had a sensitivity of 49% and specificity of 96%.
• A patient was classified as having somatization potential even if there was an organic disorder identified.
