Observation cohorts in clinical trials serve to monitor natural disease progression
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Peer-reviewed literature and clinical study registries confirm that observational cohort studies follow patient groups over time without interventions to monitor disease progression and outcomes.
<h4>Topic</h4>To compare the visual and anatomical outcomes of vitrectomy with those of observation in eyes with lamellar macular holes associated with epiretinal proliferation (LHEP).<h4>Clinical relevance</h4>LHEP is increasingly recognized in clinical practice, yet uncertainty persists regarding the visual benefits and full-thickness macular hole (FTMH) progression risk of surgical versus observational management. Reliable outcome estimates are essential for patient counseling and treatment planning.<h4>Methods</h4>A systematic review and meta-analysis. Literature search of PubMed, Embase, Scopus, Cochrane Library, and Web of Science were performed according to PRISMA guidelines and registered prospectively on PROSPERO (CRD420251089664). Eligible studies included adult patients with lamellar macular holes and LHEP managed with either vitrectomy or observation. The primary outcome was the change in best-corrected visual acuity (BCVA, logMAR). The secondary outcomes included progression to FTMH. Random-effects meta-analyses were conducted separately for surgical and observational cohorts due to limited direct comparative data. The risk of bias was assessed via the Newcastle-Ottawa Scale and the RoB 2 tool. Publication bias was evaluated via funnel plots, Egger's test, and trim-and-fill analysis.<h4>Results</h4>Seventeen studies encompassing 610 eyes met the inclusion criteria. In surgically treated eyes (14 studies; 328 eyes), vitrectomy was associated with significant visual improvement (pooled mean difference in BCVA -0.170 logMAR; 95% CI [-0.254, -0.086]; P < .001), with minimal heterogeneity (I² = 0%). In the observational cohort (5 studies; 282 eyes), no significant change in visual acuity was observed (-0.029 logMAR; 95% CI [-0.118, 0.176]; P = .695). The pooled rate of progression to FTMH was 7.5% (95% CI [4.0%,13.6%]) after vitrectomy and 4.2% (95% CI [1.4%, 11.8%]) after observation, with overlapping confidence intervals. Bias-adjusted analyses suggested a wider confidence interval for FTMH progression in the vitrectomy cohort, 12.4% (95% CI [7.4%, 20.1%]), and observational cohort, 10.1% (95% CI [3.3%, 27.2%]).<h4>Conclusion</h4>In eyes with LHEP, vitrectomy is associated with clinically meaningful visual acuity improvement, whereas no significant change was observed in pooled observational data, without a clear increase in progression to FTMH. These findings support consideration of surgical intervention in appropriately selected patients, guided by symptoms and OCT-based features.
Selecting the appropriate study design is crucial when developing clinical research. A fundamental decision is whether to collect data to address the research question using an observational study or to apply an intervention and measure outcomes in a clinical trial. There are two well-known types of observational studies: cohort studies and cross-sectional studies. In the former, a cohort of subjects is observed over time. In prospective cohort studies, observations begin in the present and follow subjects for a given time period. In retrospective cohort studies, information is collected at ti
Applications of MRI in Kidney Disease
This study has two major purposes:
1. To test developed multiple anatomic and functional MRI methods;
2. To evaluate the potentials of these MRI methods in the diagnosis, prognosis, and monitoring of the progression of renal dysfunction.
These purposes will be achieved by performing pilot studies with cohorts of patients.
This study is observational with no intervention applied for the patients. In this study, multiple anatomic and functional MRI methods will be performed with three cohorts of patients. In addition to anatomic MRI methods, non-contrast enhanced functional MRI methods will also be applied to evaluate tissue perfusion and vascular reactivity in these patients.
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