利奈唑胺治疗可预测MRSA肺炎治疗成功

旧金山——研究者在全美退伍军人事务部(VA)医院MRSA 肺炎患者的队列中发现，利奈唑胺治疗是预测临床治疗成功的唯一可干预变量。

罗德岛大学药学院的Aisling R. Caffrey博士在年度抗微生物制剂与药物治疗跨学科会议上指出：“在美国，肺炎在感染疾病相关死亡原因中列首位，但对于MRSA引起的肺炎，我们的治疗选择很少。确定临床治疗成功的独立预测因子可能有助于优化患者的治疗。”

Aisling R. Caffrey博士

为此， Caffrey博士及其合作者对2002年1月~2010年9月间收入VA医院的诊断编码为MRSA和肺炎的患者队列进行了一项回顾性研究。他们使用药房记录确定住院期间开始利奈唑胺或万古霉素治疗的时间，按照方案至少治疗3天。研究中排除在开始任何一种药物治疗后3天内死亡或出院的患者、在疗养院开始治疗的患者，以及在开始利奈唑胺或万古霉素治疗前3天内或任一药物治疗期间连续2天以上暴露于有抗MRSA活性的抗生素的患者。临床治疗成功定义为在治疗开始后14天内出院或脱离重症监护且未发生死亡、治疗转换或插管。治疗不成功定义为治疗转换、插管、出院和再次收入院，或在开始治疗后14天内死亡。他们还研究了多个临床治疗成功的潜在预测因子，包括利奈唑胺或万古霉素治疗、人口统计学和入院特征，以及合并疾病和病史。

Caffrey 博士报告了接受利奈唑胺治疗的231例患者和接受万古霉素治疗的3,501例患者的数据。患者平均年龄为70岁，且多数(98%)为男性。临床治疗成功的预测因素包括利奈唑胺治疗(OR，1.53)和既往有植入物或移植并发症(OR，1.55)。与治疗不成功相关的因素包括透析(OR，0.54)、静脉治疗(OR，0.76)、有≥3种住院操作(OR，0.53)、住院手术(OR，0.48)、泌尿系感染(OR，0.82)、既往凝血疾病(OR，0.74)、既往心内膜炎(OR，0.24)和既往截肢操作(OR，0.72)。

该研究由退伍军人事务部和辉瑞公司共同资助。

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By: DOUG BRUNK, Internal Medicine News Digital Network

SAN FRANCISCO – In a national cohort of VA patients with MRSA pneumonia, treatment with linezolid was the only modifiable variable in predicting clinical success.

"Pneumonia is the No. 1 cause of infectious disease–related deaths in the United States yet there are limited treatment options for pneumonia caused by MRSA," Aisling R. Caffrey, Ph.D., said at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. "Identification of independent predictors of clinical success can optimize patient care."
 
In an effort to identify independent predictors of clinical success in MRSA pneumonia, Dr. Caffrey, assistant professor of pharmacoepidemiology at the University of Rhode Island College of Pharmacy, and her associates conducted a retrospective cohort study of VA hospital admissions between January 2002 and September 2010 with diagnosis codes for MRSA and pneumonia. They used pharmacy records to identify initiation of linezolid or vancomycin during admission, with at least 3 days of therapy as dosed per protocol.

Patients who died or were discharged within 3 days of treatment initiation with either agent were excluded from the study, as were those whose treatment was initiated in a nursing home and those who were exposed to more than 2 consecutive days of antibiotic therapy with MRSA activity within 3 days prior to initiation of linezolid or vancomycin or during treatment with either agent.

Clinical success was defined as discharge from the hospital or intensive care unit by day 14 after treatment initiation, in the absence of death, therapy change, or intubation. Nonsuccess was defined as therapy change, intubation, discharge, and readmission, or death between treatment initiation and day 14. They also investigated numerous potential predictors of clinical success, including treatment with linezolid or vancomycin, demographics and admission characteristics, and comorbidities and medical history.

Dr. Caffrey reported data from 231 patients who received linezolid and 3,501 patients who received vancomycin. Their mean age was 70 years and most (98%) were male. Predictors of clinical success included treatment with linezolid (OR 1.53) and having a previous complication of an implant or graft (OR 1.55). Factors associated with nonsuccess included dialysis (OR 0.54), intravenous line (OR 0.76), having three or more inpatient procedures (OR 0.53), inpatient surgery (OR 0.48), urinary tract infection (0.82), previous coagulopathy (0.74), previous endocarditis (0.24), and previous amputation procedure (OR 0.72).

Dr. Caffrey acknowledged certain limitations of the study, including the reliance on diagnostic codes to ascertain the number of MRSA pneumonia cases. "We’re probably only capturing 20%-40% of MRSA diagnoses by using the diagnosis codes," she said at the meeting, which was sponsored by the American Society for Microbiology.

Low generalizability of the findings to other patient populations is another limitation: "The VA is the largest integrated health care system in the United States but it [consists of] mainly older white males with a lot of comorbidities," she explained.

She concluded that patients with MRSA pneumonia "are often complex, and identifying predictors of success is useful in maximizing clinical decision making."

The study was supported by the Department of Veterans Affairs and Pfizer.