Justification of research using systematic reviews continues to be inconsistent in clinical health science:A systematic review and meta-analysis of meta-research studies

BACKGROUND: Redundancy is an unethical, unscientific, and costly challenge in clinical health research. There is a high risk of redundancy when existing evidence is not used to justify the research question when a new study is initiated. Therefore, the aim of this study was to synthesize meta-research studies evaluating if and how authors of clinical health research studies use systematic reviews when initiating a new study. METHODS: Seven electronic bibliographic databases were searched (final search June 2021). Meta-research studies assessing the use of systematic reviews when justifying new clinical health studies were included. Screening and data extraction were performed by two reviewers independently. The primary outcome was defined as the percentage of original studies within the included meta-research studies using systematic reviews of previous studies to justify a new study. Results were synthesized narratively and quantitatively using a random-effects meta-analysis. The protocol has been registered in Open Science Framework (https://osf.io/nw7ch/). RESULTS: Twenty-one meta-research studies were included, representing 3,621 original studies or protocols. Nineteen of the 21 studies were included in the meta-analysis. The included studies represented different disciplines and exhibited wide variability both in how the use of previous systematic reviews was assessed, and in how this was reported. The use of systematic reviews to justify new studies varied from 16% to 87%. The mean percentage of original studies using systematic reviews to justify their study was 42% (95% CI: 36% to 48%). CONCLUSION: Justification of new studies in clinical health research using systematic reviews is highly variable, and fewer than half of new clinical studies in health science were justified using a systematic review. Research redundancy is a challenge for clinical health researchers, as well as for funders, ethics committees, and journals

Systematic reviews are rarely used to contextualise new results-a systematic review and meta-analysis of meta-research studies

BACKGROUND: Results of new studies should be interpreted in the context of what is already known to compare results and build the state of the science. This systematic review and meta-analysis aimed to identify and synthesise results from meta-research studies examining if original studies within health use systematic reviews to place their results in the context of earlier, similar studies. METHODS: We searched MEDLINE (OVID), EMBASE (OVID), and the Cochrane Methodology Register for meta-research studies reporting the use of systematic reviews to place results of original clinical studies in the context of existing studies. The primary outcome was the percentage of original studies included in the meta-research studies using systematic reviews or meta-analyses placing new results in the context of existing studies. Two reviewers independently performed screening and data extraction. Data were synthesised using narrative synthesis and a random-effects meta-analysis was performed to estimate the mean proportion of original studies placing their results in the context of earlier studies. The protocol was registered in Open Science Framework. RESULTS: We included 15 meta-research studies, representing 1724 original studies. The mean percentage of original studies within these meta-research studies placing their results in the context of existing studies was 30.7% (95% CI [23.8%, 37.6%], I(2)=87.4%). Only one of the meta-research studies integrated results in a meta-analysis, while four integrated their results within a systematic review; the remaining cited or referred to a systematic review. The results of this systematic review are characterised by a high degree of heterogeneity and should be interpreted cautiously. CONCLUSION: Our systematic review demonstrates a low rate of and great variability in using systematic reviews to place new results in the context of existing studies. On average, one third of the original studies contextualised their results. Improvement is still needed in researchers’ use of prior research systematically and transparently—also known as the use of an evidence-based research approach, to contribute to the accumulation of new evidence on which future studies should be based. SYSTEMATIC REVIEW REGISTRATION: Open Science registration number https://osf.io/8gkzu/ SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13643-022-02062-8

Histological outcomes in HPV-screened elderly women in Denmark

IntroductionDanish women exit cervical cancer screening at age 65 years, but 23% of cervical cancer cases occur beyond this age. In addition, due to gradual implementation of cervical cancer screening, older women are underscreened by today´s standards. A one-time screening with HPV test was therefore offered to Danish women born before 1948.MethodsRegister based study reporting histology diagnoses and conizations in women found HPV positive in the one-time screening. Number and proportion of women with severe or non-severe histology results were calculated for screened and HPV-positive women by age group or region of residence. Number of women with biopsy and/or conization per case of cervical intraepithelial neoplasia (CIN) grade 2 or worse (CIN2+) or CIN3+ were also calculated by age groups and region.Results4,479 (4.1% of screened women) had positive HPV test. 94% of these had one or more additional tests. 2,785 (62%) of HPV-positive women had histology results, and conization was performed in 1,076 (24% of HPV-positive and 1% of all screened women). HPV positivity and CIN3+ detection varied little between regions, but the proportions of HPV positive women undergoing histology varied between regions from 40% to 86% and the proportion with conization from 13% to 36%. Correspondingly, the number of histologies and conizations per CIN3+ detected varied from 5.9 to 11.2 and 1.8 to 4.7, respectively. In total, 514 CIN2+ (0.47% of screened women, 11% of HPV-positive) and 337 CIN3+ (0.31% of screened women, 7.5% of HPV-positive) were diagnosed, including 37 cervical cancer cases.DiscussionHPV screening of insufficiently screened birth cohorts can potentially prevent morbidity and mortality from cervical cancer but longer follow-up is needed to see if cancer incidence declines in the screened women in the coming years. Management strategies differed among regions which influenced the proportions undergoing biopsy/conization