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All Things Being Equal – But How? (Designing the Study)
Published in Mitchell G. Maltenfort, Camilo Restrepo, Antonia F. Chen, Statistical Reasoning for Surgeons, 2020
Mitchell G. Maltenfort, Camilo Restrepo, Antonia F. Chen
Assigning treatments is only an option with a prospective study when you are recruiting patients specifically for that study and observing them going forward. If you have a collection of data generated by years of patient care, analysis of that dataset will be a retrospective study. Even if you are collecting data prospectively for the benefit of possible future studies, the studies themselves are still retrospective because the data will not have been specifically gathered to address a research question such as “how does assigning this treatment affect outcome?”
Special Groups
Published in Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan, Comprehensive Textbook on Vitiligo, 2020
Almost all vitiligo variants have been described in late-onset disease. Dogra et al. [2] found vitiligo vulgaris to be the most common presentation (83.5%), followed by focal vitiligo (3%), mucosal vitiligo (2.2%), and vitiligo universalis (0.5%). Mucosal involvement was noted in 17% of patients, with oral mucosa being maximally involved (71%). Associated leukotrichia was seen in 47.3% of sufferers. Head and neck were the most common early sites of involvement. Family history of vitiligo was present in almost 16% of these patients, in 11.5% first-degree relatives were affected, and in 4.4% second-degree relatives were affected. However, these studies had limitations, including a retrospective study design.
Research in Psychology
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
There are three distinct kinds of longitudinal studies: panel, cohort, and retrospective. A panel usually involves a random representative sample of subjects who are followed at particular intervals over a long period, whereas a cohort study observes subjects in a similar group based on a specific variable, such as birth, geographic location or common experiences. A retrospective study involves looking at historical information such as medical records.
How to boost an obstetrician's confidence in vaginal delivery after high-intensity focused ultrasound: a comparison study on delivery outcomes
Published in International Journal of Hyperthermia, 2022
Jinping Gu, Bin Lin, Zhengyu Guo, Aixingzi Aili
There remain limitations to this study. First, because of our data collection approach and the retrospective character of the study, we are unable to detect certain aspects that may influence pregnancy and delivery following HIFU, such as obstetrics policy. A future prospective study with proper controls will be required. Second, this study did not find any unusual complications, such as uterine rupture during pregnancy or labor. We can't say if this is related to HIFU or a result of the small sample size. Third, measurement bias may occur, which is the most significant disadvantage of a retrospective study. Finally, the age range of women in the study population is large. A future prospective study would be needed to address the potential influence of age on the outcomes described here.
Prediction value of procalcitonin combining CURB-65 for 90-day mortality in community-acquired pneumonia
Published in Expert Review of Respiratory Medicine, 2021
Yu Song, Wenxue Sun, Deyu Dai, Yue Liu, Zhongyi Li, Zhennan Tian, Xiaomin Liu
The major limitations of this study were from the study population. Although the sample size is big enough, compared to the survivors, the proportion of non-survivors was relatively small. Some disadvantages of this retrospective study may not be well controlled. For example, only those patients who had their PCT tested at admission were included in the cohort, which may cause selection bias. Data regarding the antimicrobial treatment and the analysis of pathogens were insufficient to support the predictive capacity of PCT. In addition, only the data of inpatients were studied; therefore, the application of these results to outpatients needs further study. To reduce the medical costs and relieve additional financial burden to the patients and society, a single measurement of PCT was performed at the admission of each patient was performed. A serial measurement for the dynamic changes of PCT may provide more information on the severity and prognosis of CAP, therefore a more efficient and accurate predictive model may be developed.
Comparison of Right-side and Left-side Colon Cancers Following Laparoscopic Radical Lymphadenectomy
Published in Journal of Investigative Surgery, 2021
Han Deok Kwak, Jae Kyun Ju, Soo Young Lee, Chang Hyun Kim, Young Jin Kim, Hyeong Rok Kim
This retrospective study used prospective data for analysis. Between December 2009 and December 2014, 966 patients who underwent radical lymph node dissection were included. The right colon group included cecal, ascending, and hepatic flexure colon cancers, while the left colon group included splenic flexure, descending, sigmoid, and rectosigmoid junction colon cancers. The transverse colon is the boundary between midgut and hindgut, with no definite consensus in the literature on the origin, which is either the one-third or mid-portion of the transverse colon. The rectum, which is the transitional area between the hindgut and cloaca, was also excluded. In addition, patients with synchronous or multiple cancers and those with fewer than 12 harvested nodes, which could affect the comparison of sidedness, were also excluded. As most of the cases were performed with laparoscopic surgery, this analysis excluded open surgery, which represented <10%.