Identifying fibromyalgia subgroups using cluster analysis: Relationships with clinical variables.

BACKGROUND: Patients with fibromyalgia (FM) exhibit significant clinical heterogeneity, in terms of physical, social and psychological functions, as well as therapeutic responses. Here, we examined FM patients in terms of pain, physical, social and psychological variables to identify clinical subgroups that may be predictive of treatment patterns. METHODS: A total of 313 FM patients were interviewed using a structured questionnaire that included sociodemographic data, current or past FM symptoms and current use of relevant medications. A K-means cluster analysis was conducted using variables reflecting tender points, the Fibromyalgia Impact Questionnaire, Beck Depression Inventory, State-Trait Anxiety Inventor and Social Support Scale. RESULTS: Four distinct clusters were identified in these patients. Group 1 was characterized by high pain levels, severe physical and mental impairment and low social support. Group 2 had moderate pain and physical impairment, mild mental impairment and moderate social support. Group 3 had moderate pain, low physical and moderate mental impairment and low social support. Group 4 had low pain levels, nearly normal physical and mental function and high social support. Group 1 was more often a current or past smoker, more likely to have a variety of symptoms, including swelling, cognitive dysfunction, dizziness, syncope, oesophageal dysmotility, dyspepsia, irritable bladder, vulvodynia and restless leg syndrome. CONCLUSIONS: We identified four subgroups of FM patients based on pain, physical, social and psychological function. These subgroups had different clinical symptoms and medication profiles, suggesting that FM may be better managed using a more comprehensive assessment of an individual patient's symptoms. SIGNIFICANCE: FM patients can be clustered into four distinct subgroups based on clinically measurable variables - pain, physical involvement, psychological function and social support. These subgroups had different clinical symptoms and medication profiles.

The rate of and risk factors for frequent hospitalization in systemic lupus erythematosus: results from the Korean lupus network registry.

Objectives The survival rate of patients with systemic lupus erythematosus has improved in the last few decades, but the rate of hospitalization and health care costs for these patients remain higher than in the general population. Thus, we evaluated the rate of hospitalization and associated risk factors in an inception cohort of Korean patients with lupus. Methods Of the 507 patients with systemic lupus erythematosus enrolled in the KORean lupus NETwork, we investigated an inception cohort consisting of 196 patients with systemic lupus erythematosus presenting within 6 months of diagnosis based on the American College of Rheumatology classification criteria. We evaluated the causes of hospitalization, demographic characteristics, and laboratory and clinical data at the time of systemic lupus erythematosus diagnosis of hospitalized patients and during a follow-up period. We calculated the hospitalization rate as the number of total hospitalizations divided by the disease duration, and defined "frequent hospitalization" as hospitalization more than once per year. Results Of the 196 patients, 117 (59.6%) were admitted to hospital a total of 257 times during the 8-year follow-up period. Moreover, 22 (11.2%) patients were hospitalized frequently. The most common reasons for hospitalization included disease flares, infection, and pregnancy-related morbidity. In the univariate regression analysis, malar rash, arthritis, pericarditis, renal involvement, fever, systemic lupus erythematosus disease activity index > 12, hemoglobin level < 10 mg/dl, albumin level < 3.5 mg/dl, and anti-Sjögren's syndrome A positivity were associated with frequent hospitalization. Finally, multivariate analysis showed that arthritis, pericarditis, and anti-Sjögren's syndrome A antibody positivity at the time of diagnosis were risk factors for frequent hospitalization. Conclusions Our results showed that frequent hospitalization occurred in 11.2% of hospitalized patients and arthritis, pericarditis, and anti-Sjögren's syndrome A antibody positivity at the time of diagnosis were risk factors for frequent hospitalization.

Comparison of clinical and serological differences among juvenile-, adult-, and late-onset systemic lupus erythematosus in Korean patients.

OBJECTIVES: We investigated whether systemic lupus erythematosus (SLE) patients could be distinguished based on the time of disease onset and, if so, whether the groups differed in their clinical and laboratory features in ethnically homogeneous Korean patients. METHODS: We enrolled 201 SLE patients with available clinical data at the time of onset of SLE from the lupus cohort at Chonnam National University Hospital. Sociodemographic, clinical, and laboratory data, including autoantibodies, and concomitant diseases were found at the time of diagnosis of SLE by reviewing patient charts. We divided SLE patients according to age at SLE diagnosis into three groups: juvenile-onset SLE (JSLE, diagnosed at ≤ 18 years), adult-onset SLE (ASLE, diagnosed at 19-50 years), and late-onset SLE (LSLE, diagnosed at >50 years), and compared baseline demographic, clinical, and relevant laboratory findings. RESULTS: Of the 201 patients, 27 (14.4%), 149 (74.1%), and 25 (12.4%) were JSLE, ASLE, and LSLE patients, respectively. Fever, oral ulcers, nephritis, anemia, and thrombocytopenia were more common in JSLE patients than ASLE or LSLE patients (p < 0.05, < 0.05, 0.001, < 0.05, and < 0.05, respectively). However, Sjögren's syndrome was more frequent in LSLE patients than JSLE or ASLE patients (p < 0.05). Disease activity was significantly higher in JSLE patients than in ASLE or LSLE patients (p < 0.001). Anti-dsDNA and anti-nucleosome antibodies were found more frequently in JSLE patients and less frequently in LSLE patients (p < 0.05 and 0.005, respectively) and decreased complement levels were more common in JSLE patients and less common in LSLE patients (p < 0.001, 0.001, and < 0.05, respectively). CONCLUSIONS: Our results indicate that SLE patients present with different clinical and serological manifestations according to age at disease onset. JSLE patients have more severe disease activity and more frequent renal involvement and LSLE patients have milder disease activity, more commonly accompanied by Sjögren's syndrome, at disease onset.