This study aimed to estimate the prevalence of musculoskeletal disorders and rheumatic diseases among the indigenous Qom (Toba) population in the city of Rosario, Santa Fe, Argentina. An analytical cross-sectional study using methodology of the Community Oriented Program for the Control of Rheumatic Diseases (COPCORD) was performed. Subjects ≥18 years of age were interviewed by advanced students of medicine and nursing, bilingual translator-facilitators, and coordinators. Individuals with musculoskeletal pain (positive cases) were evaluated sequentially for 7 days by internists and rheumatologists for diagnosis and treatment. The study included 1656 individuals (77 % of the census population). Of these, 1020 (61.5 %) were female, with mean age of 35.3 (SD 13.9) years, and 1028 (62.0 %) were bilingual. The public health care system covers 87.1 % of the population. Musculoskeletal pain in the previous 7 days and/or at some time during their life was present in 890 subjects (53.7 %). Of those with pain in the last 7 days, 302 (64.1 %) subjects had an Health Assessment Questionnaire Disability Index (HAQ-DI) score ≥0.8. The most frequent pain sites were lumbar spine (19.3 %), knees (13.0 %), and hands (12.0 %). The prevalence of rheumatic diseases was as follows: mechanical back pain (20.1 %), rheumatic regional pain syndrome (2.9 %), osteoarthritis (4.0 %) rheumatoid arthritis (2.4 %), inflammatory back pain (0.2 %), systemic sclerosis (0.1 %), Sjögren syndrome (0.1 %), fibromyalgia (0.1 %), mixed connective tissue disease (0.06 %), and systemic lupus erythematosus (0.06 %). The prevalence of musculoskeletal disorders was 53.7 % and rheumatic diseases 29.6 %. Rheumatoid arthritis prevalence was 2.4 % using COPCORD methodology, one of the highest reported at present.

To describe the baseline and follow up epidemiological/clinical characteristics of rheumatoid arthritis (RA) in a community-based cohort of the qom population. RA (ACR criteria) patients identified (n = 40) or not (n = 25) in the previous study were included. Baseline and follow-up visits (3, 6, and 12 months) were performed. Treatment adherence and modification, disability (Health Assessment Questionnaire Disability Index-HAQ-DI), and Disease Activity [DAS-28 (ESR)] were ascertained. At 12 months, complete and incomplete lost to follow-up patients were identified. The estimated RA prevalence was 3%. The patients' mean (SD) disease duration was 110.5 (17.9) and their median delay in diagnosis 30.4 (IQR 52.8) months; mean (SD) age and years of formal education were 39.8 (1.6) and 5.3 (SD 0.3); 58 (89.2%) were female, and 89.2% were seropositive. At baseline, their mean DAS-28 (ESR) was 4.8 (SD 0.9) with 67.7% having high disease activity and 32.3% moderate; 76.9% reported HAQ-DI ≥ 0.8. At 12 months, three patients have died; 13 (20.9%) were "completely" and 19 (30.6%) "incompletely" lost to follow-up. There were favorable changes over time for disease activity (p ˂ 0.001), HAQ-DI (p ˂ 0.001), and treatment modifications (p ˂ 0.001) but no changes in treatment adherence (p = 0.260). The main cause of lost to follow-up was migration. This population has one of the highest RA prevalence rate reported. Patients had an aggressive and disabling disease, with poor adherence to treatment. Improvements of clinical parameters over time were observed.

This study assessed the overall and specific prevalence of the main rheumatic regional pain syndromes (RRPS) in four Latin-American indigenous groups. A Community Oriented Program for Control of Rheumatic Diseases (COPCORD) methodology-based census study was performed in 4240 adults (participation rate: 78.88 %) in four indigenous groups: Chontal (Oaxaca, Mexico, n = 124), Mixteco (Oaxaca, Mexico; n = 937), Maya-Yucateco (Yucatán, Mexico; n = 1523), and Qom (Rosario, Argentina; n = 1656). Subjects with musculoskeletal pain were identified using a cross-cultural, validated COPCORD questionnaire administered by bilingual personnel, and reviewed by general practitioners or rheumatologists using standardized case definitions for the 12 most frequent RRPS. The overall prevalence of RRPS was confirmed in 239 cases (5.64 %, 95 % CI: 4.98–6.37). The prevalence in each group was Chontal n = 19 (15.32 %, 95 % CI: 10.03–22.69); Maya-Yucateco n = 165 (10.83 %, 95 % CI: 9.37–12.49); Qom n = 48 (2.90 %, 95 % CI: 2.19–3.82); and Mixteco n = 7 (0.75 %, 95 % CI: 0.36–1.53). In the whole sample, the syndrome-specific prevalence was rotator cuff tendinopathy: 1.98 % (95 % CI: 1.60–2.45); lateral epicondylalgia: 0.83 % (95 % CI: 0.59–1.15); medial epicondylalgia: 0.73 % (95 % CI: 0.52–1.04); biceps tendinopathy: 0.71 % (95 % CI: 0.50–1.01); anserine syndrome: 0.64 % (95 % CI: 0.44–0.92); inferior heel pain: 0.61 % (95 % CI: 0.42–0.90); trochanteric syndrome: 0.49 % (95 % CI: 0.25–0.64); de Quervain’s tendinopathy: 0.45 % (95 % CI: 0.29–0.70); trigger finger: 0.42 % (95 % CI: 0.27–0.67); carpal tunnel syndrome: 0.28 % (95 % CI: 0.16–0.49); Achilles tendinopathy (insertional): 0.12 % (95 % CI: 0.05–0.28); and Achilles tendinopathy (non-insertional): 0.07 % (95 % CI: 0.02–0.21). Leaving aside the comparison between Maya-Yucateco and Chontal groups (p = 0.18), we found significant differences (p < 0.001) in overall RRPS prevalence between the remaining pairs of indigenous groups. Syndrome-specific prevalences were also different between groups. Our findings support the hypothesis that overall RRPS prevalence and syndrome-specific prevalences are modulated by population-specific factors.

Cutaneous involvement is frequent and heterogeneous in autoimmune diseases. In some of them, such as in systemic lupus erythematosus, dermatomyositis, systemic sclerosis and antiphospholipid syndrome, some manifestations are so relevant that are included in the classification criteria. Differential diagnosis ranges in severity. Since the disease may be life-threatening, a prompt diagnosis and treatment are mandatory. We describe a clinical case of a twenty-two-year-old woman with diagnosis of systemic lupus erythematosus and antiphospholipidic syndrome, presenting with acute, painful cutaneous lesions with necrotic aspect, fever and livedo reticularis.