Relationship between hepatitis C virus infection and type 2 diabetes mellitus:Meta-analysis

AIM:To investigate the association between hepatitis C infection and type 2 diabetes mellitus.METHODS:Observational studies assessing the relationship between hepatitis C infection and type 2 diabetes mellitus were identified via electronic and hand searches.Studies published between 1988 to March 2011 were screened,according to the inclusion criteria set for the present analysis.Authors performed separate analyses for the comparisons between hepatitis C virus(HCV) infected and not infected,and HCV infected and hepatitis B virus infected.The included studies were further subgrouped according to the study design.Heterogenity was assessed using I2 statistics.The summary odds ratios with their corresponding 95% CIs were calculated based on a random-effects model.The included studies were subgrouped according to the study design.To assess any factor that could potentially affect the outcome,results were further stratified by age group(proportion of ≥ 40 years),gender(proportion of male gender),body mass index(BMI)(pro-portion of BMI ≥ 27),and family history of diabetes(i.e.,self reported).For stability of results,a sensitivity analysis was conducted including only prospective studies.RESULTS:Combining the electronic database and hand searches,a total of 35 observational studies(in 31 articles) were identified for the final analysis.Based on random-effects model,17 studies(n = 286 084) compared hepatitis C-infected patients with those who were uninfected [summary odds ratio(OR):1.68,95% CI:1.15-2.45].Of these 17 studies,7 were both a cross-sectional design(41.2%) and cohort design(41.2%),while 3 were case-control studies(17.6%).Nineteen studies(n = 51 156) compared hepatitis C-infected participants with hepatitis B-infected(summary OR:1.92,95% CI:1.41-2.62).Of these 19 studies,4(21.1%),6(31.6%) and 9(47.4%) were cross-sectional,cohort and case-control studies,respectively.A sensitivity analysis with 3 prospective studies indicated that hepatitis C-infected patients had a higher risk of developing type 2 diabetes compared with uninfected controls(summary odds ratio:1.41,95% CI:1.17-1.7;I2 = 0%).Among hepatitis C-infected patients,male patients(OR:1.26,95% CI:1.03-1.54) with age over 40 years(summary OR:7.39,95% CI:3.82-9.38) had an increased frequency of type 2 diabetes.Some caution must be taken in the interpretation of these results because there may be unmeasured confounding factors which may introduce bias.CONCLUSION:The findings support the association between hepatitis C infection and type 2 diabetes mellitus.The direction of association remains to be determined,however.Prospective studies with adequate sample sizes are recommended.

Severe thrombocytopaenia in patients with vivax malaria compared to falciparum malaria:a systematic review and metaanalysis

Background:Plasmodium vivax is the most geographically widespread species among human malaria parasites.Immunopathological studies have shown that platelets are an important component of the host innate immune response against malaria infections.The objectives of this study were to quantify thrombocytopaenia in P.vivax malaria patients and to determine the associated risks of severe thrombocytopaenia in patients with vivax malaria compared to patients with P.falciparum malaria.Main body:A systematic review and meta-analysis of the available literature on thrombocytopaenia in P.vivax malaria patients was undertaken.Relevant studies in health-related electronic databases were identified and reviewed.The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.Fifty-eight observational studies(n=29664)were included in the current review.Severe thrombocytopaenia(<50000/mm3)to very severe thrombocytopaenia(<20000/mm3)was observed in 10.1%of patients with P.vivax infection.A meta-analysis of 11 observational studies showed an equal risk of developing severe/very severe thrombocytopaenia between the patients with P.vivax malaria and those with P.falciparum malaria(OR:1.98,95%CI:0.92-4.25).This indicates that thrombocytopaenia is as equally a common manifestation in P.vivax and P.falciparum malaria patients.One study showed a higher risk of developing very severe thrombocytopaenia in children with severe P.vivax malaria than with severe P.falciparum malaria(OR:2.80,95%CI:1.48-5.29).However,a pooled analysis of two studies showed an equal risk among adult severe cases(OR:1.19,95%CI:0.51-2.77).This indicates that the risk of developing thrombocytopaenia in P.vivax malaria can vary with immune status in both children and adults.One study reported higher levels of urea and serum bilirubin in patients with P.vivax malaria and severe thrombocytopaenia compared with patients mild thrombocytopaenia or no thrombocytopaenia,(P<0.001 in all comparisons).A pooled analysis of two other studies showed a similar proportion of bleeding episodes with thrombocytopaenia in severe P.vivax patients and severe P.falciparum patients(P=0.09).This implied that both P.vivax and P.falciparum infections could present with bleeding episodes,if there had been a change in platelet counts in the infected patients.A pooled analysis of another two studies showed an equal risk of mortality with severe thrombocytopaenia in both P.vivax and P.falciparum malaria patients(OR:1.16,95%CI:0.30-4.60).However,due to the low number of studies with small sample sizes within the subset of studies that provided clinically relevant information,our confidence in the estimates is limited.Conclusion:The current review has provided some evidence of the clinical relevance of severe thrombocytopaenia in P.vivax malaria.To substantiate these findings,there is a need for well designed,large-scale,prospective studies among patients infected with P.vivax.These should include patients from different countries and epidemiological settings with various age and gender groups represented.