Research from JAMA — Cannabinoids for Medical Use — A Systematic Review and Meta-analysis

Background— Endovascular repair of thoracic aneurysm has demonstrated low risks of mortality and spinal cord ischemia (SCI), but few large series have been published on endovascular thoracoabdominal aneurysm repair, and reports suffer from a lack of accurate comparison with similar open surgical procedures. Methods and Results— A consecutive cohort of patients with thoracic and thoracoabdominal aneurysms treated electively with endovascular repair (ER) or surgical repair (SR) techniques between 2001 and 2006 were analyzed. The association between repair technique and SCI was evaluated with univariable analysis. Adjustments for potential confounders and for the propensity to receive ER or SR were also performed in multivariable analysis. A total of 724 patients (352 ER, 372 SR) underwent repair. The mean age was 67 years, and 65% were male. ER patients were on average 9 years older ( P <0.001), had more comorbid conditions, and more frequently had prior distal repair ( P <0.001) or underwent a type I or IV repair. SR patients more commonly had chronic dissection or required type II or type III repairs ( P <0.001). Mortality at 30 days (5.7% ER versus 8.3% SR, P =0.2) and 12 months (15.6% ER versus 15.9% SR, P =0.9) was similar. A borderline difference in SCI was found between repair techniques: 4.3% of ER and 7.5% of SR patients ( P =0.08) had SCI. In patients with ER, prior distal aortic operation was associated with the development of SCI in univariable analysis (odds ratio 4.1, 95% confidence interval 1.4 to 11.7). Multivariable analysis showed that the type of required repair (type I, II, III, or IV) was the primary factor associated with the development of SCI in ER and SR patients. Conclusion— No significant difference in the incidence of mortality or SCI was found between ER and SR techniques. The strongest factor associated with SCI remains the extent of the disease. Further studies are indicated to compare ER with patients considered eligible for SR.

Nowadays, doctors face an overwhelming amount of information, even in narrow areas of interest. In response, reviews designed to summarize the large volumes of information are frequently published. When a review is done systematically, following certain criteria, and the results are pooled and analyzed quantitatively, it is called a meta-analysis. A well-designed meta-analysis can provide valuable information for researchers, policy-makers, and clinicians. However, there are many critical caveats in performing and interpreting them, and thus many ways in which meta-analyses can yield misleading information.

Obstructive sleep apnoea (OSA) is often undiagnosed before elective surgery and may predispose patients to perioperative complications. A literature search of PubMed-Medline, Web of Science, Scopus, EMBASE, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials up to November 2010 was conducted. Our search was restricted to cohort or case–control studies in adults diagnosed with OSA by screening questionnaire, oximetry, or polysomnography. Studies without controls, involving upper airway surgery, and with OSA diagnosed by ICD-9 codes alone were excluded. The primary postoperative outcomes were desaturation, acute respiratory failure (ARF), reintubation, myocardial infarction/ischaemia, arrhythmias, cardiac arrest, intensive care unit (ICU) transfer, and length of stay. Thirteen studies were included in the final analysis (n=3942). OSA was associated with significantly higher odds of any postoperative cardiac events [45/1195 (3.76%) vs 24/1420 (1.69%); odds ratio (OR) 2.07; 95% confidence interval (CI) 1.23–3.50, P=0.007] and ARF [33/1680 (1.96%) vs 24/3421 (0.70%); OR 2.43, 95% CI 1.34–4.39, P=0.003]. Effects were not heterogeneous for these outcomes (I²=0–15%, P>0.3). OSA was also significantly associated with higher odds of desaturation [189/1764 (10.71%) vs 105/1881 (5.58%); OR 2.27, 95% CI 1.20–4.26, P=0.01] and ICU transfer [105/2062 (5.09%) vs 58/3681 (1.57%), respectively; OR 2.81, 95% CI 1.46–5.43, P=0.002]. Both outcomes showed a significant degree of heterogeneity of the effect among studies (I²=57–68%, P<0.02). Subgroup analyses had similar conclusions as main analyses. The incidence of postoperative desaturation, respiratory failure, postoperative cardiac events, and ICU transfers was higher in patients with OSA.

Antibiotic exposure is the most important risk factor for Clostridium difficile infection (CDI). Most evaluations of antimicrobial risk factors have been conducted in healthcare settings. The objective of this meta-analysis was to evaluate the association between antibiotic exposure and community-associated CDI (CA-CDI) (i.e. symptom onset in the community with no healthcare facility admission within 12 weeks) and to determine the classes of antibiotics posing the greatest risk. We searched four electronic databases for subject headings and text words related to CA-CDI and antibiotics. Studies that investigated the risk of CA-CDI associated with antibiotic usage were considered eligible. Data from the identified studies were combined using a random-effects model and ORs were calculated. Of 910 citations identified, eight studies (n = 30 184 patients) met our inclusion criteria. Antibiotic exposure was associated with an increased risk of CA-CDI (OR 6.91, 95% CI 4.17–11.44, I² = 95%). The risk was greatest with clindamycin (OR 20.43, 95% CI 8.50–49.09) followed by fluoroquinolones (OR 5.65, 95% CI 4.38–7.28), cephalosporins (OR 4.47, 95% CI 1.60–12.50), penicillins (OR 3.25, 95% CI 1.89–5.57), macrolides (OR 2.55, 95% CI 1.91–3.39) and sulphonamides/trimethoprim (OR 1.84, 95% CI 1.48–2.29). Tetracyclines were not associated with an increased CDI risk (OR 0.91, 95% CI 0.57–1.45). Antibiotic exposure was an important risk factor for CA-CDI, but the risk was different amongst different antibiotic classes. The risk was greatest with clindamycin followed by fluoroquinolones and cephalosporins, whereas tetracyclines were not associated with an increased risk.