The effect of control group selection in the analysis of risk factors for extended spectrum beta-lactamase-producing Klebsiella pneumoniae infections. A prospective controlled study.

The aim was to evaluate the effect of control selection on risk factor analysis for extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) infections. Four contemporaneous case-control studies were conducted prospectively with 372 patients: Study 1 (ESBL-KP-infected vs non-infected); Study 2 (ESBL-KP-infected vs non-ESBL-KP-infected); Study 3 (all KP-infected vs non-infected); Study 4 (non-ESBL-KP-infected vs non-infected). Time at risk (TAR, i.e. duration of hospital stay) was the most significant risk factor [Study 1: odds ratio (OR): 5.74 (95% CI: 2.26-14.59; P<0.001); Study 2: 3.52 (1.47-8.43; P=0.005); Study 3: 2.68 (1.57-4.58; P<0.001)]; central venous catheterisation (CVC) was a risk factor in Study 1: 5.31 (1.67-16.82; P=0.005) and Study 3: 2.10 (1.04-4.27; P=0.04). Prior use of cephalosporins (PUC) was a risk factor only in studies with non-infected patients as controls [Study 1: 5.64 (1.90-16.72; P=0.002) and Study 3: 4.60 (2.09-10.13; P<0.001)]. The ORs were uniformly lower with 'non-ESBL-KP-infected' (TAR: 3.52; CVC: 2.07; PUC: 1.97) compared with 'non-infected' patients (TAR: 5.74; CVC: 5.31; PUC: 5.64) as control groups. Selection of control patients has a crucial role in the evaluation of risk factors for ESBL-KP infections. A consistent underestimation of the magnitude of the risk factors is observed when the control group is defined by the non-ESBL-KP-infected patients.

Inadequate treatment of ventilator-associated pneumonia: risk factors and impact on outcomes.

Initial antibiotic therapy is an important determinant of clinical outcomes in ventilator-associated pneumonia (VAP). Several studies have investigated this issue, with conflicting results. This study investigated risk factors of inadequate empirical antimicrobial therapy and its impact on outcomes for patients with a clinical diagnosis of VAP. The primary outcome was adequacy of antimicrobial therapy. Secondary outcomes were duration of mechanical ventilation, hospital and intensive care unit (ICU) lengths of stay, and mortality due to VAP. Mean age was 62.9+/-15.2 years, mean APACHE (Acute Physiological Assessment and Chronic Health Evaluation) II score was 20.1+/-8.1 and mean MODS (Multiple Organ Dysfunction Score) was 3.7+/-2.5. Sixty-nine (45.7%) of 151 patients with a clinical diagnosis of VAP received inadequate antimicrobial treatment for VAP initially. There were 100 (66.2%) episodes of VAP caused by multidrug-resistant pathogens, of which 56% were inadequately treated, whereas the rate of inadequate antimicrobial therapy for VAP caused by susceptible-drug pathogens was 25.5% (P<0.001). Multiple logistic regression analysis revealed that the risk of inadequate antimicrobial treatment was more than twice as great for patients with late-onset VAP [odds ratio (OR), 2.93; 95% confidence interval (CI), 1.30-6.64; P=0.01], and more than three times for patients with VAP caused by multidrug-resistant pathogens (OR, 3.07; 95% CI, 1.29-7.30; P=0.01) or with polymicrobial VAP (OR, 3.67; 95% CI, 1.21-11.12; P=0.02). Inadequate antimicrobial treatment was associated with higher mortality for patients with VAP. Two of three independent risk factors for treatment inadequacy were associated with the isolation and identification of micro-organisms.

Laparoscopy versus laparotomy for benign ovarian tumours.

BACKGROUND: Over the last ten years laparoscopy has become an increasingly common approach for the surgical removal of benign ovarian tumours. There remains uncertainty as to the value of this intervention. This review has been undertaken to assess the available evidence for the benefits and harms of laparoscopic surgery for benign ovarian tumours compared to laparotomy. OBJECTIVES: To determine the efficacy, safety and cost of laparoscopic surgery compared with laparotomy in women with ovarian tumours assumed to be benign. SEARCH STRATEGY: We searched electronic databases, trials registers and reference lists of published trial reports. Review articles were also searched. SELECTION CRITERIA: All randomised controlled trials comparing laparoscopy versus laparotomy for benign ovarian tumours. DATA COLLECTION AND ANALYSIS: Three reviewers independently assessed each study's eligibility and quality and extracted data. MAIN RESULTS: Six randomised controlled trials were identified involving 324 patients. Three subgroups of ovarian tumours were considered: any histological type of benign ovarian tumour, dermoid cysts and endometriomata. Surgical outcomes: The mean duration of surgery was longer in the laparoscopy group compared to the laparotomy group overall (WMD 11.39; 95% CI 0.57 to 22.22). However, heterogeneity was present with substantial inconsistency (I(2)=87%) . The heterogeneity found in these analyses was likely to reflect differences in the patient populations. Adverse effects of surgery: The pooled estimate for febrile morbidity decreased for laparoscopy compared to laparotomy (Peto OR 0.34; 95% CI 0.13 to 0.88). The odds of any adverse effect of surgery (total number of complications - surgical injury and/or post operative complications) were decreased after laparoscopic procedures (Peto OR 0.26; 95% CI 0.12 to 0.55). Short-term recovery: VAS pain scores favoured laparoscopy (WMD -2.36; 95% CI -2.07 to -2.03) andt he odds of being pain free were significantly greater for the laparoscopy group compared to laparotomy (Peto OR 7.35; 95% CI 4.3 to 12.56). Mean length of hospital stay was shorter in the laparoscopy group with reduction 2.79 days (95% CI -2.95 to -2.62) compared to laparotomy. Economic outcomes: There was a significant reduction of US$1045 (95% CI -1361 to -726.97) in the laparoscopy group compared to the laparotomy group in one trial of women with any type of benign ovarian tumour. AUTHORS' CONCLUSIONS: In women undergoing surgery for benign ovarian tumours, laparoscopy is associated with a reduction in the following; febrile morbidity, urinary tract infection, post operative complications, post operative pain, days in hospital and total cost. These findings should be interpreted with caution as only a small number of studies were identified including a total of only 324 women and not all of the important outcomes were reported in each study.