Factor analysis of the clustering of common somatic symptoms: a preliminary study

Studies of outpatient department patients indicate that somatic discomforts such as headache, neck pain, chest pain, low back pain, and gastrointestinal discomfort are commonly found in patients with multiple complaints. Clustering of some symptoms has been found in common somatic symptom analyses. Because of the complexity involved in the diagnosis of patients with multiple complaints, the aim of this study is to identify and classify patterns of somatic symptoms in individuals assessed during a health examination.

A total of 683 patients (437 males, 246 females) received a one-day physical examination and completed a structured survey during the period from May 2007 to April 2008. A physical symptoms interview was conducted, and medical and demographic data was collected.

Based on the factor analysis, 4 clusters of symptoms were identified: 1) pain symptoms, 2) cold symptoms, 3) cardiopulmonary symptoms, and 4) gastrointestinal symptoms. The distribution of symptoms differed between males and females. After varimax rotation of factor patterns, 4 extracted factors emerged. In males, the factors were 1) pain symptoms, 2) cold symptoms, 3) cardiopulmonary symptoms, and 4) gastrointestinal symptoms. In females, the factors were 1) pain symptoms, 2) cold symptoms, 3) cardiopulmonary symptoms, and 4) head and gastrointestinal symptoms.

Four clusters of somatic symptoms emerged for both males and females; however, the predominant symptoms were different in males and females. Females displayed more head-related symptoms than males. Patients should be thoroughly interviewed about additional symptoms within the same cluster after the recognition of a single somatic complaint.