Burciaga-Jimenez, Erick

We assessed the available evidence regarding adverse effects on surrogate and patient-important health outcomes of third- and fourth-generation combined oral contraceptives among premenopausal women. We performed a systematic review and meta-analysis including randomized controlled trials and observational studies comparing third- and fourth-generation combined oral contraceptives with other generation contraceptives or placebo. Studies that enrolled women aged 15 to 50 years, with at least three cycles of intervention and 6 months of follow-up were included. A total of 33 studies comprising 629,783 women were included. Low-density lipoprotein cholesterol levels were significantly lower in fourth-generation oral contraceptives (mean differences (MD): −0.24 mmol/L; [95% CI −0.39 to −0.08]), while total cholesterol was significantly increased in levonorgestrel users when compared to third-generation oral contraceptives (MD: 0.27 mmol/L; [95% CI 0.04 to 0.50]). A decreased arterial thrombosis incidence was shown in fourth-generation oral contraceptive users, as compared to levonorgestrel (incidence rate ratio (IRR): 0.41; [95% CI 0.19 to 0.86]). No difference was found in the occurrence of deep venous thrombosis between fourth-generation oral contraceptives and levonorgestrel users (IRR: 0.91; [95% CI 0.66 to 1.27]; p = 0.60; I 2 = 0%). Regarding the remaining outcomes, data were heterogeneous and showed no clear difference. In premenopausal women, the use of third- and fourth-generation oral contraceptives is associated with an improved lipid profile and lower risk of arterial thrombosis. Data were inconclusive regarding the rest of outcomes assessed. This review was registered in PROSPERO with CRD42020211133.

Evidence has raised concerns regarding the association between funding sources and doubtful data. Our main outcome was to analyze trends on funding sources in articles published from 1990 to 2020 in the more influential journals of internal and general medicine. In this meta-epidemiological study, we included peer-reviewed studies from the 10 highest impact journals in general and internal medicine published between January 1990 and February 2020 based on published original research according to the 2018 InCites Journal of Citation Reports, these consisted of the following: The New England Journal of Medicine, The Lancet, JAMA, BMJ, JAMA Internal Medicine, Annals of Internal Medicine, PLOS Medicine, Cachexia, BMC Medicine, and Mayo Clinic Proceedings. Two reviewers working in duplicate extracted data regarding year of publication, study design, and sources of funding. In total, 496 articles were found; of these, 311 (62.7%) were observational studies, 167 (33.7%) were experimental, and 16 (3.2%) were secondary analyses. Percentages of grant sources through the years were predominantly from government (60%), industry (23.83%), and non-governmental (16.06%) organizations. The percentage of industry subsidies tended to decrease, but this was not significant in a linear regression model (r=0.02, p≥0.05). Government and non-government funding sources showed a trend to decrease in the same univariate analysis with both significant associations (r=0.21, p ≤0.001 and r=0.10, p≤0.001, respectively). The main funding source in medical research has consistently been government aid. Despite previous reported data, no association was found between the source of funding and statistically significant results favoring study authors’ hypothesis.