W McGuire1, L Clerihew. 1. Centre for Reviews and Dissemination, Hull York Medical School, University of York, York, UK. william.mcguire@hyms.ac.uk
Abstract
BACKGROUND: The validity and applicability of before-after studies compared to randomised controlled trials (RCTs) of fluconazole prophylaxis for very low birthweight (VLBW) infants is uncertain. OBJECTIVES: The aim was to examine whether the study design (before-after studies compared to RCTs) affected the estimate of effect size yielded in meta-analyses and to explore possible causes for any differences detected. METHODS: A systematic review and meta-analysis of before-after studies, which assessed the effect of fluconazole prophylaxis on the incidence of invasive fungal infection in VLBW infants, was undertaken. Data were compared with estimates generated from meta-analyses of RCTs. Funnel plots were examined for evidence of publication bias. RESULTS: Meta-analysis of 11 before-after studies found a reduced risk of invasive fungal infection following introduction of fluconazole prophylaxis: RR 0.19 (95% CI 0.13 to 0.27). This estimate is significantly lower than the estimate generated from meta-analysis of RCTs: RR 0.48 (95% CI 0.31 to 0.73). Inspection of a funnel plot of before-after studies revealed that smaller studies with large effects sizes contributed an excess of data points. CONCLUSIONS: Publication bias may be an important cause of effect size estimate inflation of before-after studies. Data from before-after studies of antifungal prophylaxis for VLBW infants should be interpreted and applied cautiously. Evidence to guide policy and practice for should instead be derived from well-designed RCTs.
BACKGROUND: The validity and applicability of before-after studies compared to randomised controlled trials (RCTs) of fluconazole prophylaxis for very low birthweight (VLBW) infants is uncertain. OBJECTIVES: The aim was to examine whether the study design (before-after studies compared to RCTs) affected the estimate of effect size yielded in meta-analyses and to explore possible causes for any differences detected. METHODS: A systematic review and meta-analysis of before-after studies, which assessed the effect of fluconazole prophylaxis on the incidence of invasive fungal infection in VLBW infants, was undertaken. Data were compared with estimates generated from meta-analyses of RCTs. Funnel plots were examined for evidence of publication bias. RESULTS: Meta-analysis of 11 before-after studies found a reduced risk of invasive fungal infection following introduction of fluconazole prophylaxis: RR 0.19 (95% CI 0.13 to 0.27). This estimate is significantly lower than the estimate generated from meta-analysis of RCTs: RR 0.48 (95% CI 0.31 to 0.73). Inspection of a funnel plot of before-after studies revealed that smaller studies with large effects sizes contributed an excess of data points. CONCLUSIONS: Publication bias may be an important cause of effect size estimate inflation of before-after studies. Data from before-after studies of antifungal prophylaxis for VLBW infants should be interpreted and applied cautiously. Evidence to guide policy and practice for should instead be derived from well-designed RCTs.
Authors: Roland Abou Jaoude; Adel Zauk; Charlotte Morel; Diane McClure; Michael Lamacchia; Vincent A DeBari Journal: Med Microbiol Immunol Date: 2014-04-11 Impact factor: 3.402
Authors: Sofia Aliaga; Reese H Clark; Matthew Laughon; Thomas J Walsh; William W Hope; Daniel K Benjamin; David Kaufman; Antonio Arrieta; Daniel K Benjamin; P Brian Smith Journal: Pediatrics Date: 2014-01-20 Impact factor: 9.703