Flores-Rodríguez, Andrea

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.

Background: Combined therapy with levothyroxine (LT4)/L-triiodothyronine (LT3) has garnered attention among clinicians and patients as a potential treatment alternative to LT4 monotherapy. The objective of this study was to compare the benefits and harms of LT4/LT3 combined therapy and LT4 monotherapy for patients with hypothyroidism. Methods: A systematic search in MEDLINE, Scopus, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials was performed by a librarian from inception date until September 2020. Randomized clinical trials and quasiexperimental studies comparing combined therapy (LT4/LT3) versus monotherapy (LT4) for adult patients with hypothyroidism were considered for inclusion. Independent data extraction was performed by paired reviewers. A meta-analysis comparing standardized mean differences of the effect of each therapy was performed on clinical outcomes and patient preferences. Proportions of adverse events and reactions were assessed narratively. Results: A total of 1398 references were retrieved, from which 18 fulfilled the inclusion criteria. Results supported by evidence at low-to-moderate certainty evidence did not display a difference in treatment effect between therapies on clinical status, quality of life, psychological distress, depressive symptoms, and fatigue; all measured with standardized questionnaires. Furthermore, meta-analysis of patient preferences revealed higher proportions of choice for combined therapy (43%) when compared with monotherapy (23%) or having no preference (30%). When evaluating treatment adverse events or adverse reactions, similar proportions were observed between treatment groups; meta-analysis was not possible. Conclusions: The available evidence at low-to-moderate certainty demonstrates that there is no difference in clinical outcomes between LT4/LT3 combined therapy and LT4 monotherapy for treating hypothyroidism in adults, except for a higher proportion of patient preferring combined therapy. Adverse events and reactions appear to be similar across both groups, however, this observation is only narrative. These results could inform shared decision-making conversations between patients with hypothyroidism and their clinicians. PROSPERO Registration ID: CRD42020202658.