Benefits of Therapeutic Drug Monitoring of Vancomycin: A Systematic Review and Meta-Analysis

Background and Objective

The necessity of therapeutic drug monitoring (TDM) for vancomycin is controversial. The objective of the current review was to evaluate the available evidence for the necessity of TDM in patients given vancomycin to treat Gram-positive infections.

Methods

Medline, Embase, Web of Sciences, the Cochrane Library and two Chinese literature databases (CNKI, CBM) were searched. Randomized controlled studies and observational studies that compared the clinical outcomes of TDM groups vs. non-TDM groups were included. Two reviewers independently extracted the data. The primary outcome was clinical efficacy of therapy. Secondary outcomes included vancomycin associated nephrotoxicity, duration of vancomycin therapy, length of hospital stay, and mortality. Meta-analysis was performed using the Mantel-Haenszel fixed effect method (FEM). Odds ratios (ORs) or weighted mean differences (WMD) with 95% confidence intervals (95%CIs) were calculated for categorical and continuous outcomes, respectively.

Results

One randomized controlled trial (RCT) and five cohort studies were included in the meta-analysis. Compared with non-TDM groups, TDM groups had significantly higher rates of clinical efficacy (OR = 2.62, 95%CI 1.34–5.11 P = 0.005) and decreased rates of nephrotoxicity (OR = 0.25, 95%CI 0.13–0.48 P<0.0001). Subgroup analyses showed that TDM group had significantly higher rates of clinical efficacy in both cohort studies subgroup (OR = 3.04, 95%CI 1.34–6.90) and in Asian population subgroup (OR = 3.04, 95%CI 1.34–6.90). TDM group had significantly decreased rates of nephrotoxicity in all subgroup. There was no significant difference in duration of vancomycin therapy (WMD = −0.40, 95%CI −2.83–2.02 P = 0.74) or length of stay (WMD = −1.01, 95%CI −7.51-5.49 P = 0.76) between TDM and non-TDM groups. Subgroup analyses showed there were no differences in duration of vancomycin therapy. Only one study reported mortality rates.

Conclusions

Studies to date show that TDM significantly increases the rate of clinical efficacy and decreases the rate of nephrotoxicity in patients treated with vancomycin.     

Coffee Consumption and Risk of Breast Cancer: An Up-To-Date Meta-Analysis

Objectives

This updated meta-analysis was conducted to assess the association between coffee consumption and breast cancer risk.

Methods

We conducted a systematic search updated July 2012 to identify observational studies providing quantitative estimates for breast cancer risk in relation to coffee consumption. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and generalized least square trend estimation was used to assess dose–response relationships.

Results

A total of 26 studies (16 cohort and 10 case–control studies) on coffee intake with 49497 breast cancer cases were included in the meta-analysis. The pooled RR showed a borderline significant influence of highest coffee consumption (RR = 0.96; 95% CI 0.93–1.00), low-to moderate coffee consumption (RR = 0.99; 95% CI 0.95–1.04), or an increment of 2 cups/day of coffee consumption (RR = 0.98; 95% CI 0.97–1.00) on the risk of breast cancer. In stratified analysis, a significant inverse association was observed in ER-negative subgroup. However, no significant association was noted in the others.

Conclusions

Our findings suggest that increased coffee intake is not associated with a significantly reduced risk of breast cancer, but we observe an inverse association in ER-negative subgroup analysis. More large studies are needed to determine subgroups to obtain more valuable data on coffee drinking and breast cancer risk.     

The Association between MTHFR Gene Polymorphisms and Hepatocellular Carcinoma Risk: A Meta-Analysis

Background

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and hepatocellular carcinoma (HCC) risk was inconsistent and underpowered. To clarify the effects of MTHFR gene polymorphisms on the risk of HCC, a meta-analysis of all available studies relating C677T and/or A1298C polymorphisms of MTHFR gene to the risk of HCC was conducted.

Methods

The authors searched PubMed, EMBASE, Cochrane Library, Web of Science, and Chinese Biomedical Literature database (CBM) for the period up to July 2012. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity.

Results

Finally, 12 studies with 2,351 cases and 4,091 controls were included for C677T polymorphism and 6 studies with 1,333 cases and 1,878 controls were included for A1298C polymorphism. With respect to A1298C polymorphism, significantly decreased HCC risk was found in the overall population (CC vs. AA: OR = 0.660, 95%CI 0.460–0.946, P = 0.024; recessive model: OR = 0.667, 95%CI = 0.470–0.948, P = 0.024). In subgroup analyses, significantly decreased HCC risk was found in Asian population (CC vs. AA: OR = 0.647, 95%CI = 0.435–0.963; P = 0.032) and population-based studies (CC vs. AA: OR = 0.519, 95%CI = 0.327–0.823; P = 0.005). With respect to C677T polymorphism, no significant association with HCC risk was demonstrated in overall and stratified analyses.

Conclusions

We concluded that MTHFR A1298C polymorphism may play a protective role in the carcinogenesis of HCC. Further large and well-designed studies are needed to confirm this association.     

Prehypertension Is Not Associated with All-Cause Mortality: A Systematic Review and Meta-Analysis of Prospective Studies

Objectives

Quantitative associations between prehypertension or its two separate blood pressure (BP) ranges and cardiovascular disease (CVD) or all-cause mortality have not been reliably documented. In this study, we performed a comprehensive systematic review and meta-analysis to assess these relationships from prospective cohort studies.

Methods

We conducted a comprehensive search of PubMed (1966-June 2012) and the Cochrane Library (1988-June 2012) without language restrictions. This was supplemented by review of the references in the included studies and relevant reviews identified in the search. Prospective studies were included if they reported multivariate-adjusted relative risks (RRs) and corresponding 95% confidence intervals (CIs) of CVD or all-cause mortality with respect to prehypertension or its two BP ranges (low range: 120–129/80–84 mmHg; high range: 130–139/85–89 mmHg) at baseline. Pooled RRs were estimated using a random-effects model or a fixed-effects model depending on the between-study heterogeneity.

Results

Thirteen studies met our inclusion criteria, with 870,678 participants. Prehypertension was not associated with an increased risk of all-cause mortality either in the whole prehypertension group (RR: 1.03; 95% CI: 0.91 to 1.15, P = 0.667) or in its two separate BP ranges (low-range: RR: 0.91; 95% CI: 0.81 to 1.02, P = 0.107; high range: RR: 1.00; 95% CI: 0.95 to 1.06, P = 0.951). Prehypertension was significantly associated with a greater risk of CVD mortality (RR: 1.32; 95% CI: 1.16 to 1.50, P<0.001). When analyzed separately by two BP ranges, only high range prehypertension was related to an increased risk of CVD mortality (low-range: RR: 1.10; 95% CI: 0.92 to 1.30, P = 0.287; high range: RR: 1.26; 95% CI: 1.13 to 1.41, P<0.001).

Conclusions

From the best available prospective data, prehypertension was not associated with all-cause mortality. More high quality cohort studies stratified by BP range are needed.     

Chemotherapy Plus Best Supportive Care versus Best Supportive Care in Patients with Non-Small Cell Lung Cancer: A Meta-Analysis of Randomized Controlled Trials

Background

The use of chemotherapy has been proposed to increase the effectiveness of best supportive care (BSC) in patients with non-small cell lung cancer (NSCLC). Previous trials reported inconsistent findings regarding the efficacy and safety of chemotherapy on overall survival (OS) and treatment-related mortality. We performed a systematic review and meta-analysis to evaluate the effects of chemotherapy plus BSC versus BSC alone on survival of patients with NSCLC.

Methodology and Principal Findings

We systematically searched PubMed, EmBase, and the Cochrane Central Register of Controlled Trials for relevant literature. All eligible studies included patients with NSCLC who had received chemotherapy and BSC or BSC alone. All eligible studies measured at least 1 of the following outcomes: OS or treatment-related mortality. Overall, patients that received chemotherapy plus BSC had significant longer OS than those that received BSC alone (HR, 0.76; 95%CI, 0.69–0.84; P<0.001). Additionally, chemotherapy plus BSC as compared to BSC alone resulted in a 28% RR reduction (95%CI: 12–40; P = 0.001) in 6-month mortality, 11% RR reduction (95%CI: 8–15; P<0.001) in 12-month mortality, and 5% RR reduction (95%CI: 1–8; P = 0.02) in 2-year mortality. Toxicity was greater in patients that received chemotherapy plus BSC.

Conclusion/Significance

Chemotherapy plus BSC increased the OS and reduced the 6-month, 12-month, and 2-year mortality of NSCLC patients.     

Meta-Analysis of the Association between COX-2 Polymorphisms and Risk of Colorectal Cancer Based on Case–Control Studies

Objective

Cyclooxygenase-2 (COX-2) is an inducible enzyme converting arachidonic acid to prostaglandins and playing important roles in inflammatory diseases as well as tumor development. Previous studies investigating the association between COX-2 polymorphisms and colorectal cancer (CRC) risk reported conflicting results. We performed a meta-analysis of all available studies to explore this association.

Methods

All studies published up to October 2013 on the association between COX-2 polymorphisms and CRC risk were identified by searching electronic databases PubMed, EMBASE, and Cochrane library. The association between COX-2 polymorphisms and CRC risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs).

Results

Ten studies with 6,774 cases and 9,772 controls were included for −1195A>G polymorphism, 13 studies including 6,807 cases and 10,052 controls were available for −765G>C polymorphism, and 8 studies containing 5,121 cases and 7,487 controls were included for 8473T>C polymorphism. With respect to −765G>C polymorphism, we did not find a significant association with CRC risk when all eligible studies were pooled into the meta-analysis. However, in subgroup analyses by ethnicity and cancer location, with a Bonferroni corrected alpha of 0.05/2, statistical significant increased CRC risk was found in the Asian populations (dominant model CC+CG vs. GG: OR = 1.399, 95%CI: 1.113–1.760, P = 0.004) and rectum cancer patients (CC vs. GG: OR = 2.270, 95%CI: 1.295–3.980, P = 0.004; Recessive model CC vs. CG+GG: OR = 2.269, 95%CI: 1.297–3.970, P = 0.004). In subgroup analysis according to source of control, no significant association was detected. With respect to −1195A>G and 8473T>C polymorphisms, no significant association with CRC risk was demonstrated in the overall and subgroup analyses.

Conclusions

The present meta-analysis suggests that the COX-2 −765G>C polymorphism may be a risk factor for CRC in Asians and rectum cancer patients. Further large and well-designed studies are needed to confirm this association.     

Efficacy and Safety of Adding Clopidogrel to Aspirin on Stroke Prevention among High Vascular Risk Patients: A Meta-Analysis of Randomized Controlled Trials

Objectives

Whether clopidogrel should be added to aspirin for stroke prevention remained controversial for the risk of hemorrhagic complications. This meta-analysis was aimed to assess the efficacy and safety of adding clopidogrel to aspirin on stroke prevention in high vascular risk patients, and to provide evidence for a suitable duration of dual antiplatelet therapy.

Methods

We searched PubMed, EMBase, OVID and Cochrane Central Register of Controlled Trials (up to June, 2013) for randomized controlled trials evaluating the efficacy and safety of clopidogrel plus aspirin versus aspirin alone in high vascular risk patients. Comparisons of stroke and hemorrhagic complications between treatment groups were expressed by the pooled Relative Risks (RRs) with 95% Confidence Intervals (CIs).

Results

Fifteen trials with a total of 97692 intention-to-treat participants were included with duration of follow-up ranging from 7 days to 3.6 years. Dual antiplatelet therapy reduced all stroke by 21% (RR: 0.79, 95% CI: 0.73–0.85) with no evidence of heterogeneity across the trials (P = 0.27, I ² = 17%).The effects were consistent between short-term subgroup (≤1 month, RR: 0.76, 95% CI: 0.67–0.85) and long-term subgroup (≥3 months, RR: 0.81, 95% CI: 0.73–0.89). The risk of major bleeding was not significantly increased by dual antiplatelet therapy in short-term subgroup (RR: 1.11, 95% CI: 0.91–1.36), while significantly increased in long-term subgroup (RR: 1.52, 95% CI: 1.36–1.69). Long-term dual antiplatelet therapy substantially increased the risk of intracranial bleeding (RR: 1.76, 95% CI: 1.22–2.54).

Conclusions

This meta-analysis demonstrates that short-term combination of clopidogrel and aspirin is effective and safe for stroke prevention in high vascular risk patients. Long-term combination therapy substantially increases the risk of major bleeding and intracranial bleeding.     

Association between Irrigation Fluids,Washout Volumes and Risk of Local Recurrence of Anterior Resection for Rectal Cancer: A Meta-Analysis of 427 Cases and 492 Controls

Background

Rectal washout can prevent local recurrence after anterior resection of rectal cancer. Few studies have focused particularly on the association between irrigation fluids volume or agents and the risk of local recurrence after anterior resection of rectal cancer.

Objective

To estimate the association between irrigation fluids types, volumes of rectal washout and risk of local recurrence after anterior resection for cancer.

Data Sources

Relevant studies were identified by a search of Medline, Embase, Wiley Online Library, China National Knowledge Infrastructure, Cochrane Oral Health Group Specialized Register, Wanfang databases and Google Website from their inception until October 18,2013.

Study Selection

Studies reporting the association between rectal washout types and volumes and risk of local recurrence after anterior resection for cancer were included.

Interventions

Eligible studies used rectal washout. Control groups were defined as no washout.

Study Appraisal and Synthesis Methods

Random-effects model were used to obtain summary estimates of RR and 95% CI, with Stata version 11 and RevMan 5.2.5 softwares used. The quality of report was appraised in reference to the MINORS item.

Results

Of the 919 rectal cancer patients in 8 included studies, a total of 61(6.64%) cases of local recurrence were reported, with a pooled RR 0.51 (95%CI = 0.28–0.92, P = 0.03). The RRs 0.37 and 0.39 in normal saline and washout volume (≥1500 ml normal saline) subgroup, respectively, indicated that rectal washout with normal saline, or ≥1500 ml in volume could significantly reduce local recurrence (LR) rate (95% CI = 0.17–0.79, P = 0.01; 95% CI = 0.18–0.87, P = 0.02) after anterior resection for cancer.

Limitation

The included studies were non-randomized observational studies, with diversity of study designs.

Conclusion

Rectal washout with normal saline alone can reduce the risk of local recurrence in patients with resectable rectal cancer, and 1.5 liters rectal washout in volume is recommended.     

Tumor Necrosis Factor Alpha rs1800629 Polymorphism and Risk of Cervical Lesions: A Meta-Analysis

Background

Tumor necrosis factor- alpha (TNF-α) is an inflammatory cytokine which may play important role on the immune response may control the progression of cervical lesions. There is a possible association between TNF-α rs1800629 G/A polymorphism and cervical lesions, but previous studies report conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α rs1800629 polymorphism and cervical lesions risk.

Methods

Literature searches of Pubmed, Embase, Web of Science, and Wanfang databases were performed for all publications on the association between TNF-α rs1800629 polymorphism and cervical lesions through December 15, 2012. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the strength of the association.

Results

Twenty individual case-control studies from 19 publications with a total of 4,146 cases and 4,731 controls were finally included into the meta-analysis. Overall, TNF-α rs1800629 polymorphism was significantly associated with increased risk of cervical lesions under two main genetic comparison models (For A versus G: OR 1.22, 95%CI 1.04–1.44, P = 0.017; for AA versus GG: OR 1.32, 95%CI 1.02–1.71, P = 0.034). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α rs1800629 polymorphism and increased risk of cervical lesions in Caucasians but not in Asians. Subgroup analysis by the types of cervical lesions showed that there was a significant association between TNF-α rs1800629 polymorphism and increased risk of cervical cancer (For A versus G: OR 1.24, 95%CI 1.05–1.47, P = 0.011; for AA versus GG: OR 1.31, 95%CI 1.01–1.70, P = 0.043; for AA/GA versus GG: OR 1.25, 95%CI 1.01–1.54, P = 0.039).

Conclusion

The meta-analysis suggests that TNF-α rs1800629 polymorphism is associated with increased risk of cervical lesions, especially in Caucasians.     

Downregulated E-Cadherin Expression Indicates Worse Prognosis in Asian Patients with Colorectal Cancer: Evidence from Meta-Analysis

Background

Epithelial-mesenchymal transition (EMT) plays a crucial role in the progression and aggressiveness of colorectal carcinoma. E-cadherin is the best-characterized molecular marker of EMT, but its prognostic significance for patients with CRC remains inconclusive.

Methodology

Eligible studies were searched from the PubMed, Embase and Web of Science databases. Correlation between E-cadherin expression and clinicopathological features and prognosis was analyzed. Subgroup analysis was also performed according to study location, number of patients, quality score of studies and cut-off value.

Principal Findings

A total of 27 studies comprising 4244 cases met the inclusion criteria. Meta-analysis suggested that downregulated E-cadherin expression had an unfavorable impact on overall survival (OS) of CRC (n = 2730 in 14 studies; HR = 2.27, 95%CI: 1.63–3.17; Z = 4.83; P = 0.000). Subgroup analysis indicated that low E-cadherin expression was significantly associated with worse OS in Asian patients (n = 1054 in 9 studies; HR = 2.86, 95%CI: 2.13–3.7, Z = 7.11; P = 0.000) but not in European patients (n = 1552 in 4 studies; HR = 1.14, 95%CI: 0.95–1.35, Z = 1.39; P = 0.165). In addition, reduced E-cadherin expression indicated an unfavorable OS only when the cut off value of low E-cadherin expression was >50% (n = 512 in 4 studies; HR = 2.08, 95%CI 1.45–2.94, Z = 4.05; P = 0.000). Downregulated E-cadherin expression was greatly related with differentiation grade, Dukes'' stages, lymphnode status and metastasis. The pooled OR was 0.36(95%CI: 0.19–0.7, Z = 3.03, P = 0.002), 0.34(95%CI: 0.21–0.55, Z = 6.61, P = 0.000), 0.49(95%CI: 0.32–0.74, Z = 3.02, P = 0.002) and 0.45(95%CI: 0.22–0.91, Z = 3.43, P = 0.001), respectively.

Conclusions

This study showed that low or absent E-cadherin expression detected by immunohistochemistry served as a valuable prognostic factor of CRC. However, downregulated E-cadherin expression seemed to be associated with worse prognosis in Asian CRC patients but not in European CRC patients. Additionally, this meta-analysis suggested that the negative threshold of E-cadherin should be >50% when we detected its expression in the immunohistochemistry stain.     

E-Selectin Gene Polymorphisms and Essential Hypertension in Asian Population: An Updated Meta-Analysis

Objective

Epidemiological studies have shown that E-selectin gene polymorphisms (A561C and C1839T) may be associated with essential hypertension (EH), but the results are conflicting in different ethnic populations. Thus, we performed this meta-analysis to investigate a more authentic association between E-selectin gene polymorphisms and the risk of EH.

Methods

We searched the relevant studies for the present meta-analysis from the following electronic databases: PubMed, Embase, Cochrane Library, Google Scholar, Web of Science, Wanfang Data, and China National Knowledge Infrastructure (CNKI). Odds ratios (OR) with 95% confidence interval (CI) were used to evaluate the strength of the association between E-selectin gene polymorphisms and EH susceptibility. The pooled ORs were performed for dominant model, allelic model and recessive model. The publication bias was examined by Begg’s funnel plots and Egger’s test.

Results

A total of eleven studies met the inclusion criteria. All studies came from Asians. Ten studies (12 cohorts) evaluated the A561C polymorphism and EH risk, including 2,813 cases and 2,817 controls. The pooled OR was 2.280 (95%CI: 1.893–2.748, P<0.001) in dominant model, 5.284 (95%CI: 2.679–10.420, P<0.001) in recessive model and 2.359 (95%CI: 1.981–2.808, P = 0.001) in allelic model. Four studies (six cohorts) evaluated C1839T polymorphism and EH risk, including 1,700 cases and 1,681 controls. The pooled OR was 0.785 (95%CI: 0.627–0.983, P = 0.035) in dominant model, 1.250 (95%CI: 0.336–4.652, P = 0.739) in recessive model and 0.805 (95%CI: 0.649–0.999, P = 0.049) in allelic model.

Conclusion

The current meta-analysis concludes that the C allele of E-selectin A561C gene polymorphism might increase the EH risk in Asian population, whereas the T allele of E-selectin C1839T gene polymorphism might decrease the EH risk.     

Aspirin Use and Risk of Age-Related Macular Degeneration: A Meta-Analysis

Background

Age-related macular degeneration (AMD) is the main cause of blindness and the curative options are limited. The objective of this meta-analysis was to determine the association between aspirin use and risk of AMD.

Methods

A comprehensive literature search was performed in PubMed, Embase, Web of Science, and reference lists. A meta-analysis was performed by STATA software.

Results

Ten studies involving 171729 individuals examining the association between aspirin use and risk of AMD were included. Among the included studies, 2 were randomized-controlled trials (RCTs), 4 were case-control studies and 4 were cohort studies. The relative risks (RRs) were pooled using a random-effects model. Relative risks with 95% confidence intervals (CIs) of aspirin use as a risk for AMD. The pooled RR of 10 included studies between the use of aspirin and risk of AMD was 1.09 (95% CI, 0.96–1.24). The same result was detected in early and late stage AMD subgroup analysis. In the subgroup analyses, the pooled RR of RCTs, case-control studies and cohort studies were 0.81 (95% CI, 0.64–1.02), 1.02 (95% CI, 0.92–1.14) and 1.08 (95% CI, 0.91–1.28), respectively.

Conclusions

The use of aspirin was not associated with the risk of AMD.     

Postoperative Use of the Chemopreventive Vitamin K2 Analog in Patients with Hepatocellular Carcinoma

Aim

To evaluate the chemopreventive efficacy of vitamin K2 (VK2) analog in patients with hepatocellular carcinoma (HCC) after curative hepatic resection or local ablation, since a recent randomized control trial (RCT) and systematic review have given contradictory results.

Methods

MEDLINE, EMBASE and Cochrane library databases were systematically searched through the end of May 2012. Meta-analysis of RCTs and cohort studies was performed to estimate the effects of the VK2 analog on tumor recurrence rate and overall survival (OS). Risk ratios (RRs) and 95% confidence intervals (95% CIs) were calculated.

Results

Six RCTs and one cohort study involving a total of 930 patients were included. VK2 analog therapy did not reduce the 1-year recurrence rate, with a pooled RR of 0.67 (95% CI 0.39–1.13, p = 0.13). However, VK2 analog therapy was associated with a significant reduction in the 2- and 3-year tumor recurrence rates, with respective pooled RRs of 0.65 (95% CI 0.51–0.83, p<0.001) and 0.70 (95% CI = 0.58–0.85, p<0.001). The therapy was also associated with a significant improvement in 1-, 2-, and 3-year OS, with respective pooled RRs of 1.03 (95% CI 1.01–1.05, p = 0.02), 1.11 (95% CI 1.03–1.19, p = 0.005) and 1.14 (95% CI 1.02–1.28, p = 0.02). None of the studies reported adverse effects attributable to VK2 analog therapy.

Conclusion

The VK2 analog may reduce recurrence rate after 1 year and improve OS in HCC patients as early as 1 year. However, these findings should be considered preliminary since the majority of patients came from an RCT with survival data out to only 1 year. More extensive studies with larger sample sizes and longer follow-up are needed.     

Significant Association of Glutathione S-Transferase T1 Null Genotype with Prostate Cancer Risk: A Meta-Analysis of 26,393 Subjects

Background

Recent studies on the association between Glutathione S-transferase T1 (GSTT1) polymorphism and risk of prostate cancer showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies.

Methods

Data were collected from the following electronic databases: Pubmed, Embase, and Chinese Biomedical Database (CBM). The odds ratio (OR) and its 95% confidence interval (95%CI) was used to assess the strength of the association. We summarized the data on the association between GSTT1 null genotype and risk of prostate cancer in the overall population, and performed subgroup analyses by ethnicity, adjusted ORs, and types of controls.

Results

Ultimately, a total of 43 studies with a total of 26,393 subjects (9,934 cases and 16,459 controls) were eligible for meta-analysis. Overall, there was a significant association between GSTT1 null genotype and increased risk of prostate cancer (OR = 1.14, 95%CI 1.01–1.29, P = 0.034). Meta-analysis of adjusted ORs also showed a significant association between GSTT1 null genotype and increased risk of prostate cancer (OR = 1.34, 95%CI 1.09–1.64, P = 0.006). Similar results were found in the subgroup analyses by ethnicity and types of controls.

Conclusion

This meta-analysis demonstrates that GSTT1 null genotype is associated with prostate cancer susceptibility, and GSTT1 null genotype contributes to increased risk of prostate cancer.     

Association between CD14 Promoter -159C/T Polymorphism and the Risk of Sepsis and Mortality: A Systematic Review and Meta-Analysis

Background

Recent studies on the association between CD14-159C/T polymorphism and sepsis showed inconclusive results. Accordingly, we conducted a comprehensive literature search and a meta-analysis to determine whether the CD14-159C/T polymorphism conferred susceptibility to sepsis or was associated with increased risk of death from sepsis.

Methodology

Data were collected from the following electronic databases: PubMed, Embase, Medline, Web of Knowledge, and HuGE Navigator, with the last report up to June 15, 2012. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association. We summarized the data on the association between CD14-159C/T polymorphism and sepsis in the overall population and subgroup by ethnicity and sepsis subtype.

Principal Findings

A total of 16 studies on sepsis morbidity (1369 cases and 2382 controls) and 4 studies on sepsis mortality (731 sepsis patients) met the inclusion criteria for meta-analysis. Overall analysis showed no strong evidences of association with sepsis susceptibility under any genetic model. However, slight associations were found in Asian populations (dominant model: OR = 1.38, 95%CI = 0.96–1.98, P = 0.08) and septic shock patients (dominant model: OR = 1.72, 95%CI 1.05–2.83, P = 0.03; allelic model: OR = 1.52, 95%CI 1.09–2.12, P = 0.01) in the stratified analysis. Moreover, there was borderline association between CD14-159C/T and sepsis mortality under the dominant genetic model (OR = 1.44, 95%CI = 0.98–2.11, P = 0.06).

Conclusions/Significance

This meta-analysis suggests that the CD14-159C/T polymorphism may not be a significant susceptibility factor in the risk of sepsis and mortality. Only weak associations were observed in Asian populations and septic shock patients. More studies based on larger sample sizes and homogeneous sepsis patients are needed to confirm these findings.     

Diabetes Mellitus and Risk of Bladder Cancer: A Meta-Analysis of Cohort Studies

Background

Increasing evidence suggests that diabetes mellitus (DM) may be associated with an increased risk of bladder cancer. To provide a quantitative assessment of this association, we evaluated the relation between DM and incidence and mortality of bladder cancer in an updated meta-analysis of cohort studies. Methods We identified cohort studies by searching the EMBASE and MEDLINE databases, through 31 March 2012. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with random-effects models.

Results

A total of 29 cohort studies (27 articles) were included in this meta-analysis. DM was associated with an increased incidence of bladder cancer (RR 1.29, 95% CI: 1.08–1.54), with significant evidence of heterogeneity among these studies (p<0.001, I² = 94.9%). In stratified analysis, the RRs of bladder cancer were 1.36 (1.05–1.77) for diabetic men and 1.28 (0.75–2.19) for diabetic women, respectively. DM was also positively associated with bladder cancer mortality (RR 1.33, 95% CI: 1.14–1.55), with evident heterogeneity between studies (p = 0.002, I² = 63.3%). The positive association was observed for both men (RR 1.54, 95% CI: 1.30–1.82) and women (RR 1.50, 95% CI: 1.05–2.14).

Conclusion

These findings suggest that compared to non-diabetic individuals, diabetic individuals have an increased incidence and mortality of bladder cancer.     

Active Smoking and Risk of Metabolic Syndrome: A Meta-Analysis of Prospective Studies

Background

Epidemiological evidence suggests that smoking has been associated with emergence of metabolic syndrome. However, data on this issue are inconsistent and controversial. We therefore conducted a meta-analysis to examine the association between smoking and metabolic syndrome.

Methodology and Principal Findings

We searched the Medline, Embase and the Cochrane Library database up to March 2012 to identify prospective cohort studies related to smoking and metabolic syndrome. Reference lists of retrieved articles were also reviewed. Summary effect estimates were derived using a random-effects model and stratified by gender, smoking dose, follow-up duration and geographical area. Primary analysis of 13 studies involving 56,691 participants and 8,688 cases detected a significant positive association between active smoking and risk of metabolic syndrome (pooled relative risk [RR] 1.26, 95% CI: 1.10–1.44). Estimates of effects were substantially consistent in the stratified analyses. In the dose-response analysis, risk of metabolic syndrome was stronger for active male smokers (pooled RR 1.34, 95% CI: 1.20–1.50) than it was for former male smokers (pooled RR 1.19, 95% CI: 1.00–1.42), and greater for heavy smokers (pooled RR 1.42, 95% CI: 1.27–1.59) compared with light smokers (pooled RR 1.10, 95% CI: 0.90–1.35). No evidence of statistical publication bias was found (Egger'' s test P = 0.227, Begg'' s test P = 0.113).

Conclusions

Active smoking is associated with development of metabolic syndrome. Smoking cessation appears to reduce the risk of metabolic syndrome.     

Genetic Polymorphism of the Kinesin-Like Protein KIF1B Gene and the Risk of Hepatocellular Carcinoma

Background

Frequent deletions of the kinesin-like protein gene 1B (KIF1B) have been reported in neural tumors. Recently, a genome-wide association study revealed an association between polymorphisms in the KIF1B gene and the risk of hepatocellular carcinoma (HCC), and several case-control studies have further investigated this relationship. However, these studies have yielded controversial results. We therefore performed a meta-analysis to derive a more precise estimation of the association between the KIF1B gene polymorphisms and HCC risk.

Methodology/Principal Finding

PubMed, EMBASE, the ISI Web of Science and the CNKI databases were systematically searched to identify relevant studies. A total of 5 studies containing 13 cohorts with 5,773 cases and 6,404 controls were included. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to assess the strength of the associations. Subgroup analyses were conducted based on ethnicities, sample sizes and quality scores. Overall, the G allele at rs17401966 of the KIF1B gene was associated with a significantly decreased risk for HCC (OR  = 0.81, 95%CI: 0.70–0.93; P = 0.003). Furthermore, subgroup analyses showed that the G allele at rs17401966 of the KIF1B gene significantly reduced the risk for HCC in Chinese cohorts (OR  = 0.76, 95%CI: 0.64–0.90; P = 0.002), large-sample-size cohorts (OR  = 0.80, 95%CI: 0.73–0.88, P<0.01) and high-quality cohorts (OR  = 0.78, 95%CI: 0.71–0.87, P<0.01). However, no significant associations were found in small-sample-size cohorts, studies with low-quality scores and when excluding the cohorts from the study reporting the original discovery.

Conclusion/Significance

These findings demonstrate that the presence of the G allele at rs17401966 of the KIF1B gene may decrease the risk for HCC and suggest that KIF1B may play a critical role in the development of HCC. High-quality studies with larger sample sizes and different ethnic populations will be of great value to further confirm these findings.     

Obesity and Risk of Colorectal Cancer: A Systematic Review of Prospective Studies

Background

Mounting evidence indicates that obesity may be associated with the risk of colorectal cancer (CRC). To conduct a systematic review of prospective studies assessing the association of obesity with the risk of CRC using meta-analysis.

Methodology/Principal Findings

Relevant studies were identified by a search of MEDLINE and EMBASE databases before January 2012, with no restrictions. We also reviewed reference lists from retrieved articles. We included prospective studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the association between general obesity [measured using body mass index (BMI)] or central obesity [measured using waist circumference (WC)] and the risk of colorectal, colon, or rectal cancer. Approximately 9, 000, 000 participants from several countries were included in this analysis. 41 studies on general obesity and 13 studies on central obesity were included in the meta-analysis. The pooled RRs of CRC for the obese vs. normal category of BMI were 1.334 (95% CI, 1.253–1.420), and the highest vs. lowest category of WC were 1.455 (95% CI, 1.327–1.596). There was heterogeneity among studies of BMI (P<0.001) but not among studies of WC (P = 0.323).

Conclusions

Both of general and central obesity were positively associated with the risk of CRC in this meta-analysis.     

CD133 Expression and the Prognosis of Colorectal Cancer: A Systematic Review and Meta-Analysis

Objective

CD133 has recently been reported as a marker of cancer stem-like cells in colorectal cancer (CRC). However, its predictive value in CRC still remains controversial. In this study, we aimed to evaluate the association between the expression of CD133 and clinicopathological features and the outcome of CRC patients by performing a meta-analysis.

Methods

A comprehensive literature search for relevant studies published up to December 2012 was performed using PubMed, MEDLINE and ISI Web of Science. Only articles in which CD133 antigen was detected in situ localisation by immunohistochemical staining were included. This meta-analysis was done using RevMan 4.2 software.

Results

We found that a total of 15 studies involving 810 CD133-high and 1487 CD133-low patients met the inclusion criteria for the analysis of 5-year overall survival (OS) rate. In a random-effects model, the results showed that CD133-high expression in colorectal cancer was an independent prognostic marker correlating with both OS rate (RR = 0.67, 95%CI 0.54–0.82, P<0.01) and disease free survival (DFS) rate (RR = 0.71, 95%CI 0.52–0.96, P = 0.03). CD133-high expression was also associated with more T3,4 tumor invasion, N positive and vascular invasion cases, corresponding to a risk difference of 1.12 (95%CI 1.01–1.23, P = 0.03), 1.31 (95%CI 1.06–1.63, P = 0.01) and 1.24 (95%CI 1.08–1.41, P<0.01), respectively. However, when types of histology, lymphatic invasion and distant metastasis were considered, CD133 overexpression was not significantly related with these clinicopathological parameters.

Conclusion

Our meta-analysis results suggest that CD133 is an efficient prognostic factor in CRC. Higher CD133 expression is significantly associated with poorer clinical outcome and some clinicopathological factors such as T category, N category and vascular invasion in CRC patients.