Retrospective review of the clinical manifestations and outcomes in Puerto Ricans with idiopathic inflammatory myopathies.

BACKGROUND: The idiopathic inflammatory myopathies (IIM) are a heterogeneous group of conditions characterized by chronic inflammation of muscles, resulting in skeletal muscle weakness. Racial differences are apparent in the clinical manifestations and outcome of IIM. No previous studies have been conducted to evaluate the clinical manifestations and outcome of Puerto Ricans with IIM.

OBJECTIVE: The objective of this study was to describe demographic characteristics, clinical features, and functional outcome of Puerto Rican patients with IIM.

METHODS: Medical records at a university medical center were reviewed retrospectively to collect data regarding demographic factors, initial presentation, diagnostic tests, serologic markers, treatment, and disease course. A Functional Grading Scale was administered to 40 of the patients with IIM to determine their functional status.

RESULTS: Fifty patients with IIM were identified. Eight patients had polymyositis (PM), 23 patients had dermatomyositis (DM), 2 patients had DM/PM with coexistent malignancy, 12 patients had juvenile DM, and 5 patients had DM/PM with an associated other rheumatologic disease. At diagnosis, proximal muscle weakness was present in all patients, 15 (30%) had myalgias, 5 (10%) patients had dysphagia, and 87% had elevation of serum muscle enzymes. Visceral involvement was rare. Interstitial fibrosis was identified in only 2 patients (1 juvenile DM and 1 PM). Twenty-six patients (51%) achieved complete remission. The mean score for the Functional Grading Scale was 28.6 (maximum 30). The lowest scores were seen for patients with disease duration of less than 2 years.

CONCLUSION: Puerto Ricans with IIM in this survey showed a low presence of visceral involvement, high remission rate, and low mortality.