Ward M M, Donald F
Department of Veterans Affairs Palo Alto Health Care System, California, USA.
Arthritis Rheum. 1999 Apr;42(4):780-9. doi: 10.1002/1529-0131(199904)42:4<780::AID-ANR23>3.0.CO;2-M.
Pneumonia due to Pneumocystis carinii has been increasingly reported in patients with connective tissue diseases, but the frequency of this complication is not known. We sought to determine the frequency of P carinii pneumonia (PCP) in patients with connective tissue diseases, and to determine the role that a hospital's acquired immunodeficiency syndrome (AIDS)-related experience may have in the diagnosis of PCP in these patients.
We used a state hospitalization registry to identify all patients with PCP and either rheumatoid arthritis, systemic lupus erythematosus, Wegener's granulomatosis, polymyositis, dermatomyositis, polyarteritis nodosa, or scleroderma who had an emergent or urgent hospitalization in California from 1983 to 1994. We compared patient and hospital characteristics between these patients and patients with connective tissue diseases hospitalized with other types of pneumonia.
Two hundred twenty-three patients with connective tissue diseases were diagnosed with PCP in the 12-year study period. The frequency of PCP ranged from 89 cases/10,000 hospitalizations/year in patients with Wegener's granulomatosis to 2 cases/10,000 hospitalizations/year in patients with rheumatoid arthritis. Compared with 5,457 patients with connective tissue diseases and pneumonia due to other organisms, patients with PCP were more likely to be younger, to be male, to have private medical insurance, and to have systemic lupus erythematosus, Wegener's granulomatosis, inflammatory myopathy, or polyarteritis nodosa rather than rheumatoid arthritis, and were less likely to be African American. Hospital size, teaching status, urban/rural location, proportion of admissions due to AIDS or PCP, and proportion of patients with pneumonia undergoing bronchoscopy were each associated with the likelihood of diagnosis of PCP in univariate analyses, but only the number of patients with PCP being treated at a hospital (odds ratio [OR] 1.03 for each additional 10 cases/year, 95% confidence interval [95% CI] 1.01-1.05) was associated with the likelihood of diagnosis of PCP in multivariate analyses. Patients were also somewhat more likely to be diagnosed with PCP if there had previously been a case of PCP in a patient with a connective tissue disease at the same hospital (OR 135, 95% CI 0.98-1.85). In-hospital mortality was 45.7%, and was unrelated to hospital characteristics.
PCP is an uncommon, but often fatal, occurrence in patients with connective tissue disease. A hospital's prior experience with patients with PCP is associated with the likelihood that this condition is diagnosed in patients with connective tissue diseases who present with pneumonia, suggesting that diagnostic suspicion is an important factor in the correct identification of affected patients.
卡氏肺孢子虫肺炎在结缔组织病患者中的报道日益增多，但这种并发症的发生率尚不清楚。我们试图确定结缔组织病患者中卡氏肺孢子虫肺炎（PCP）的发生率，并确定医院的获得性免疫缺陷综合征（AIDS）相关经验在这些患者PCP诊断中可能发挥的作用。
我们利用一个州住院登记系统，识别出1983年至1994年在加利福尼亚州紧急或加急住院的所有患有PCP且患类风湿关节炎、系统性红斑狼疮、韦格纳肉芽肿、多发性肌炎、皮肌炎、结节性多动脉炎或硬皮病的患者。我们比较了这些患者与因其他类型肺炎住院的结缔组织病患者的患者及医院特征。
在12年的研究期间，223例结缔组织病患者被诊断为PCP。PCP的发生率从韦格纳肉芽肿患者的每年89例/10000次住院到类风湿关节炎患者的每年2例/10000次住院不等。与5457例因其他病原体导致肺炎的结缔组织病患者相比，PCP患者更可能较年轻、为男性、拥有私人医疗保险，患有系统性红斑狼疮、韦格纳肉芽肿、炎性肌病或结节性多动脉炎而非类风湿关节炎，且不太可能是非裔美国人。在单因素分析中，医院规模、教学状况、城乡位置、因AIDS或PCP入院的比例以及接受支气管镜检查的肺炎患者比例均与PCP的诊断可能性相关，但在多因素分析中，仅医院治疗的PCP患者数量（每增加10例/年，优势比[OR]为1.03，95%置信区间[95%CI]为1.01 - 1.05）与PCP的诊断可能性相关。如果同一家医院之前有结缔组织病患者发生过PCP病例，患者也更有可能被诊断为PCP（OR为1.35，95%CI为0.98 - 1.85）。住院死亡率为45.7%，与医院特征无关。
PCP在结缔组织病患者中虽不常见，但往往是致命的。医院之前对PCP患者的经验与肺炎结缔组织病患者中该疾病的诊断可能性相关，这表明诊断怀疑是正确识别受影响患者的重要因素。
