本文报告1例B型胰岛素抵抗综合征（type B insulin resistance syndrome, TBIRS）合并混合性结缔组织病患者。该患者为54岁男性，患有混合性结缔组织病，表现为多尿、口干、多饮、体重持续减轻、高血糖、黑棘皮症，实验室检查提示胰岛素抵抗、高胰岛素血症，最终诊断为TBIRS，给予糖皮质激素、羟氯喹及胰岛素增敏剂治疗。2周后患者多尿、口干、多饮减轻，血糖平稳，1个月后，黑棘皮症减轻，体重稳定，血糖平稳。TBIRS属于自身免疫疾病，在临床上罕见，患者多为中年女性，大部分病例以高血糖、高胰岛素血症表现为主，低血糖少见，主要依据临床表现诊断，治疗方案需根据症状及伴发的自身免疫疾病综合考虑。临床上TBIRS多伴有系统性红斑狼疮，而本文报道病例为TBIRS伴混合性结缔组织病，较罕见。TBIRS患者预后差，死亡率高，早期诊断及治疗有助于改善其预后。本例患者首次应用新型胰岛素增敏剂西格列他钠控制血糖，具有良好降糖效果，且证实联合应用免疫抑制剂治疗有效，为临床上早期发现此类疾病及精准治疗提供重要指导价值。

This study reports a case of type B insulin resistance syndrome (TBIRS) complicated by mixed connective tissue disease. The patient, a 54-year-old male diagnosed with mixed connective tissue disease, exhibited symptoms including polyuria, dry mouth, polydipsia, continuous weight loss, hyperglycemia, and acanthosis nigricans. Laboratory tests confirmed insulin resistance and hyperinsulinemia, leading to a final diagnosis of TBIRS. The patient was treated with glucocorticoids, hydroxychloroquine, and insulin sensitizer. After two weeks, the patient showed improvement in polyuria, dry mouth, and polydipsia, with stable blood glucose levels. One month later, the patient's acanthosis nigricans improved, weight stabilized, and blood glucose levels remained stable. TBIRS is an autoimmune disease, more commonly seen in middle-aged females. The majority of cases present with hyperglycemia and hyperinsulinemia, while hypoglycemia is rare. Diagnosis is primarily based on clinical manifestations, and treatment plans should be tailored according to the symptoms and associated autoimmune diseases. TBIRS is often associated with systemic lupus erythematosus. However, the case reported in this study presents a rare instance of TBIRS with mixed connective tissue disease. The prognosis for TBIRS patients is poor, with a high mortality rate. Early diagnosis and treatment can help improve outcomes. In this case, a novel insulin sensitizer chiglitazar sodium was used for blood glucose control for the first time, demonstrating good hypoglycemic efficacy. The combined use of immunosuppressive agents proved effective, providing important guidance for early detection and precise treatment of such diseases in clinical practice.