Antinuclear antibody negativity ups risk of malignancy in adult-onset dermatomyositis
Antinuclear antibody (ANA) negativity appears to increase the likelihood of developing malignancy in patients with adult-onset dermatomyositis (DM) within 3 years of diagnosis of their DM, according to a recent study.
“Particularly close follow-up and frequent malignancy screening may be warranted in ANA− individuals with DM,” the authors said.
This retrospective cohort study compared the incidence of amyopathic disease, risk of malignancy and clinical findings in ANA+ and ANA− patients with adult-onset DM, determined by enzyme-linked immunosorbent assay.
A total of 231 patients were included, of whom 140 (61 percent) were ANA+ and 91 (39 percent) were ANA–. The frequency of dysphagia (15 percent vs 26 percent; p=0.033) and heliotrope rash (38 percent vs 53 percent; p=0.026) was lower in ANA+ patients compared with ANA− patients.
Overall, malignancy developed in 54 patients (23 percent) within 3 years of diagnosis of DM. More ANA− patients developed malignancy than ANA+ patients (43 percent vs 11 percent; p<0.001).
In multivariable analysis, ANA positivity was strongly associated with a lower likelihood of malignancy (odds ratio [OR], 0.16; p<0.001). In contrast, there was no association found between ANA positivity and amyopathic disease (OR, 0.94; p=0.87).
This study was limited by its retrospective nature, according to the authors.
An earlier study by Fardet and colleagues found the following factors to be independently associated with an underlying malignancy in DM patients: age at diagnosis >52 years (hazard ratio [HR], 7.24; 95 percent CI, 2.35–22.31), a rapid onset of skin and/or muscular symptoms (HR, 3.11; 1.07–9.02), presence of skin necrosis (HR, 3.84; 1.00–14.85) or periungual erythema (HR, 3.93; 1.16–13.24) and a low baseline level of complement factor C4 (HR, 2.74; 1.11–6.75). [Medicine (Baltimore) 2009;88:91-97]