scholarly journals Do Case-Control Studies Always Estimate Odds Ratios?

2020 ◽  
Author(s):  
Jeremy A Labrecque ◽  
Myriam M G Hunink ◽  
M Arfan Ikram ◽  
M Kamran Ikram
Keyword(s):  
Incidence Rate ◽  
Case Control Study ◽  
Case Control ◽  
Small Sample ◽  
Incidence Density ◽  
Odds Ratios ◽  
Case Control Studies ◽  
Rate Ratios ◽  
Study Designs ◽  
Control Study

Abstract Case-control studies are an important part of the epidemiologic literature, yet confusion remains about how to interpret estimates from different case-control study designs. We demonstrate that not all case-control study designs estimate odds ratios. On the contrary, case-control studies in the literature often report odds ratios as their main parameter even when using designs that do not estimate odds ratios. Only studies using specific case-control designs should report odds ratios, whereas the case-cohort and incidence-density sampled case-control studies must report risk ratio and incidence rate ratios, respectively. This also applies to case-control studies conducted in open cohorts, which often estimate incidence rate ratios. We also demonstrate the misinterpretation of case-control study estimates in a small sample of highly cited case-control studies in general epidemiologic and medical journals. We therefore suggest that greater care be taken when considering which parameter is to be reported from a case-control study.

Case-control studies in neurosurgery

2014 ◽  
Vol 121 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Cody L. Nesvick ◽  
Clinton J. Thompson ◽  
Frederick A. Boop ◽  
Paul Klimo
Keyword(s):  
Logistic Regression ◽  
Observational Studies ◽  
Case Control Study ◽  
Low Cost ◽  
Case Control ◽  
Odds Ratios ◽  
Case Control Studies ◽  
Inappropriate Use ◽  
Kaplan Meier ◽  
Control Study

Object Observational studies, such as cohort and case-control studies, are valuable instruments in evidence-based medicine. Case-control studies, in particular, are becoming increasingly popular in the neurosurgical literature due to their low cost and relative ease of execution; however, no one has yet systematically assessed these types of studies for quality in methodology and reporting. Methods The authors performed a literature search using PubMed/MEDLINE to identify all studies that explicitly identified themselves as “case-control” and were published in the JNS Publishing Group journals (Journal of Neurosurgery, Journal of Neurosurgery: Pediatrics, Journal of Neurosurgery: Spine, and Neurosurgical Focus) or Neurosurgery. Each paper was evaluated for 22 descriptive variables and then categorized as having either met or missed the basic definition of a case-control study. All studies that evaluated risk factors for a well-defined outcome were considered true case-control studies. The authors sought to identify key features or phrases that were or were not predictive of a true case-control study. Those papers that satisfied the definition were further evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist. Results The search detected 67 papers that met the inclusion criteria, of which 32 (48%) represented true case-control studies. The frequency of true case-control studies has not changed with time. Use of odds ratios (ORs) and logistic regression (LR) analysis were strong positive predictors of true case-control studies (for odds ratios, OR 15.33 and 95% CI 4.52–51.97; for logistic regression analysis, OR 8.77 and 95% CI 2.69–28.56). Conversely, negative predictors included focus on a procedure/intervention (OR 0.35, 95% CI 0.13–0.998) and use of the word “outcome” in the Results section (OR 0.23, 95% CI 0.082–0.65). After exclusion of nested case-control studies, the negative correlation between focus on a procedure/intervention and true case-control studies was strengthened (OR 0.053, 95% CI 0.0064–0.44). There was a trend toward a negative association between the use of survival analysis or Kaplan-Meier curves and true case-control studies (OR 0.13, 95% CI 0.015–1.12). True case-control studies were no more likely than their counterparts to use a potential study design “expert” (OR 1.50, 95% CI 0.57–3.95). The overall average STROBE score was 72% (range 50–86%). Examples of reporting deficiencies were reporting of bias (28%), missing data (55%), and funding (44%). Conclusions The results of this analysis show that the majority of studies in the neurosurgical literature that identify themselves as “case-control” studies are, in fact, labeled incorrectly. Positive and negative predictors were identified. The authors provide several recommendations that may reverse the incorrect and inappropriate use of the term “case-control” and improve the quality of design and reporting of true case-control studies in neurosurgery.

scholarly journals Bias control in the analysis of case–control studies with incidence density sampling

2019 ◽  
Vol 48 (6) ◽  
pp. 1981-1991 ◽  
Author(s):  
Yin Bun Cheung ◽  
Xiangmei Ma ◽  
K F Lam ◽  
Jialiang Li ◽  
Paul Milligan
Keyword(s):  
Logistic Regression ◽  
Reduction Method ◽  
Case Control Study ◽  
Case Control ◽  
Bias Reduction ◽  
Incidence Density ◽  
Haemophilus Influenzae Type ◽  
Case Control Studies ◽  
Residual Time ◽  
Control Study

Abstract Background Previous simulation studies of the case–control study design using incidence density sampling, which required individual matching for time, showed biased estimates of association from conditional logistic regression (CLR) analysis; however, the reason for this is unknown. Separately, in the analysis of case–control studies using the exclusive sampling design, it has been shown that unconditional logistic regression (ULR) with adjustment for an individually matched binary factor can give unbiased estimates. The validity of this analytic approach in incidence density sampling needs evaluation. Methods In extensive simulations using incidence density sampling, we evaluated various analytic methods: CLR with and without a bias-reduction method, ULR with adjustment for time in quintiles (and residual time within quintiles) and ULR with adjustment for matched sets and bias reduction. We re-analysed a case–control study of Haemophilus influenzae type B vaccine using these methods. Results We found that the bias in the CLR analysis from previous studies was due to sparse data bias. It can be controlled by the bias-reduction method for CLR or by increasing the number of cases and/or controls. ULR with adjustment for time in quintiles usually gave results highly comparable to CLR, despite breaking the matches. Further adjustment for residual time trends was needed in the case of time-varying effects. ULR with adjustment for matched sets tended to perform poorly despite bias reduction. Conclusions Studies using incidence density sampling may be analysed by either ULR with adjustment for time or CLR, possibly with bias reduction.

scholarly journals O6E.6 Occupational exposures and ALS: international collaborations and new ways to identify risk factors

2019 ◽  
Vol 76 (Suppl 1) ◽  
pp. A61.1-A61
Author(s):  
Susan Peters ◽  
Leonard van den Berg ◽  
Jan Veldink ◽  
Roel Vermeulen
Keyword(s):  
Risk Factors ◽  
Case Control Study ◽  
Disease Onset ◽  
Occupational Exposures ◽  
Case Control ◽  
Incidence Density ◽  
Recall Bias ◽  
Case Control Studies ◽  
Incident Cases ◽  
Control Study

BackgroundAssociations between occupational exposures and amyotrophic lateral sclerosis (ALS) have been suggested, but results are inconsistent. Case-control studies are best suited for inclusion of clinically confirmed incident cases, but prone to recall bias. Cohort studies are free from recall bias and may have pre-symptomatic blood stored, to inform about exposures (e.g. lead) well before disease onset.MethodsAn ongoing nation-wide ALS case-control study has been conducted in the Netherlands since 2006 (currently over 3000 cases and 4500 controls) to study risk factors and possible gene-environment interactions. Part of this study has been pooled with case-control studies from Ireland and Italy (Euro-MOTOR), where the same questionnaire was administered.ResultsWithin the Euro-MOTOR study, ∼1300 cases and ∼2600 controls had full job histories available. Occupational exposures to a range of agents were assessed using job-exposure matrices. Analyses were adjusted for age, sex, centre, education, smoking and alcohol. We found significant associations between ALS and exposure to silica (OR 1.73, 95% CI 1.28–2.33), extremely low-frequency magnetic fields (OR 1.16, 95% CI 1.01–1.33) and electric shocks (OR 1.23, 95% CI 1.05–1.43), independent of the other occupational exposures studied.Future perspectivesA nested ALS case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. 219 people who died from ALS have been identified, and pre-symptomatic blood samples from 168 of these cases are available for analyses. Three controls per case were selected by incidence density sampling matched by age at recruitment, sex and study centre. Metal concentrations will be analysed in the erythrocytes. This would be the first prospective study on the association between exposure to metals and ALS.ConclusionEach study design has its strengths and weaknesses, and ALS should be investigated in a range of (occupational) studies to gain better understanding of its aetiology.

scholarly journals Correlation between matrix metalloproteinase-2 polymorphisms and first and recurrent atherosclerotic ischemic stroke events: a case–control study

2021 ◽  
Vol 49 (6) ◽  
pp. 030006052110229
Author(s):  
Ying Li ◽  
Qing-rong Ouyang ◽  
Juan Li ◽  
Xiao-rong Chen ◽  
Lin-lin Li ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Matrix Metalloproteinase ◽  
Chinese Population ◽  
Case Control Study ◽  
Case Control ◽  
Matrix Metalloproteinase 2 ◽  
Odds Ratios ◽  
Control Study

Objective To determine the associations between matrix metalloproteinase-2 (MMP-2, encoded by the MMP2 gene) 1306C/T and 735C/T polymorphisms and first and recurrent ischemic stroke in a Chinese population. Methods Patients with first and recurrent ischemic stroke were included. Serum MMP-2 was measured, and MMP2 1306C/T and 735C/T polymorphisms were detected. The associations between MMP2 1306C/T and 735C/T polymorphisms and first and recurrent ischemic stroke were analyzed. Results Serum MMP-2 in patients with first and recurrent ischemic stroke was significantly higher compared with controls, and patients with recurrent ischemic stroke had higher MMP-2 than those with first ischemic stroke. The frequency of the CC genotype and C allele of MMP2 735C/T was highest in patients with recurrent ischemic stroke, followed by patients with first ischemic stroke, and controls. Conversely, the genotype and allele of MMP2 1306C/T did not significantly differ between groups. The CC genotype of MMP2 735C/T was independently associated with first and recurrent ischemic stroke (odds ratios = 1.45 and 1.64, respectively), as was the C allele of MMP2 735C/T (odds ratios = 1.68 and 1.77, respectively). Conclusions The CC genotype and C allele of MMP2 735C/T were associated with first and recurrent ischemic stroke in a Chinese population.

Association between blood transfusion and ventilator-associated events: a nested case-control study

2021 ◽  
pp. 1-6
Author(s):  
Wen Wang ◽  
Qiao He ◽  
Shichao Zhu ◽  
Mingqi Wang ◽  
Yan Kang ◽  
...  
Keyword(s):  
Blood Transfusion ◽  
Case Control Study ◽  
Case Control ◽  
Incidence Density ◽  
Cox Models ◽  
Hospital System ◽  
Increased Risk ◽  
Healthcare Associated ◽  
Nested Case Control ◽  
Control Study

Abstract Objectives: The association between blood transfusion and ventilator-associated events (VAEs) has not been fully understood. We sought to determine whether blood transfusion increases the risk of a VAE. Design: Nested case-control study. Setting: This study was based on a registry of healthcare-associated infections in intensive care units at West China Hospital system. Patients: 1,657 VAE cases and 3,293 matched controls were identified. Methods: For each case, 2 controls were randomly selected using incidence density sampling. We defined blood transfusion as a time-dependent variable, and we used weighted Cox models to calculate hazard ratios (HRs) for all 3 tiers of VAEs. Results: Blood transfusion was associated with increased risk of ventilator-associated complication-plus (VAC-plus; HR, 1.47; 95% CI, 1.22–1.77; P <.001), VAC-only (HR, 1.29; 95% CI, 1.01–1.65; P = .038), infection-related VAC-plus (IVAC-plus; HR, 1.78; 95% CI, 1.33–2.39; P < .001), and possible ventilator-associated pneumonia (PVAP; HR, 2.10; 95% CI, 1.10–3.99; P = .024). Red blood cell (RBC) transfusion was also associated with increased risk of VAC-plus (HR, 1.34; 95% CI, 1.08–1.65; P = .007), IVAC-plus (HR, 1.70; 95% CI, 1.22–2.36; P = .002), and PVAP (HR, 2.49; 95% CI, 1.17–5.28; P = .018). Compared to patients without transfusion, the risk of VAE was significantly higher in patients with RBC transfusions of >3 units (HR, 1.73; 95% CI, 1.25–2.40; P = .001) but not in those with RBC transfusions of 0–3 units. Conclusion: Blood transfusions were associated with increased risk of all tiers of VAE. The risk was significantly higher among patients who were transfused with >3 units of RBCs.

scholarly journals Safety and Effectiveness of Transforaminal Epiduroscopic Laser Ablation in Single Level Disc Disease: A Case-Control Study

2018 ◽  
Vol 1 (21;1) ◽  
pp. E643-E650
Author(s):  
Dong Ah Shin
Keyword(s):  
Laser Ablation ◽  
Nucleus Pulposus ◽  
Case Control Study ◽  
Case Control ◽  
Small Sample ◽  
Control Group ◽  
Disc Disease ◽  
Single Level ◽  
The Mean ◽  
Control Study

Background: The non-operative treatment of herniated intervertebral discs has long been a fundamental challenge. A novel technique of laser ablation to ablate the nucleus pulposus under a transforaminal epiduroscope (TELA system, Lutronics, Seoul, Republic of Korea) was recently developed. Objective: The purpose of this study was to evaluate the safety and effectiveness of transforaminal epiduroscopic laser ablation (TELA) for selective ablation of the nucleus pulposus in single-level disc disease. Study Design: Prospective case control study Setting: Multicenter study Methods: This study included a group of 56 patients who underwent transforaminal epiduroscopic laser ablation (TELA) and 56 patients who underwent selective transforaminal epidural block (STEB) for single-level disc disease. Visual analog scale (VAS), Oswestry Disability Index (ODI), and SF-12 were assessed at admission and at 1, 3, 6, and 12 months postoperatively. Results: The mean VAS of back pain was lower for the TELA group than for the STEB group 12 months postoperative (P < 0.05). The mean ODI was lower in the TELA group than in the STEB group at 12 months postoperatively (P < 0.05). There were no major complications related to the TELA and STEB procedures. Limitations: The primary limitation is a small sample size. The control group was created from a database which was prospectively collected in a different time line. Conclusions: The TELA procedure is superior to the STEB procedure in terms of patients reporting less pain and better quality of life over a year. TELA may be a reasonable alternative to conventional interventions or open surgery in single-level disc disease. Key words: Laser-assisted spinal endoscopy, disc decompression, Nd:YAG laser, laser ablation, intervertebral disc disease, lumbar spine

scholarly journals The Acquisition of Multidrug-Resistant Bacteria in Patients Admitted to COVID-19 Intensive Care Units: A Monocentric Retrospective Case Control Study

2020 ◽  
Vol 8 (11) ◽  
pp. 1821
Author(s):  
Elisa G. Bogossian ◽  
Fabio S. Taccone ◽  
Antonio Izzi ◽  
Nicolas Yin ◽  
Alessandra Garufi ◽  
...  
Keyword(s):  
Intensive Care ◽  
Risk Analysis ◽  
Case Control Study ◽  
Multidrug Resistant ◽  
Case Control ◽  
Incidence Density ◽  
Resistant Bacteria ◽  
Competing Risk Analysis ◽  
Multidrug Resistant Bacteria ◽  
Control Study

Whether the risk of multidrug-resistant bacteria (MDRB) acquisition in the intensive care unit (ICU) is modified by the COVID-19 crisis is unknown. In this single center case control study, we measured the rate of MDRB acquisition in patients admitted in COVID-19 ICU and compared it with patients admitted in the same ICU for subarachnoid hemorrhage (controls) matched 1:1 on length of ICU stay and mechanical ventilation. All patients were systematically and repeatedly screened for MDRB carriage. We compared the rate of MDRB acquisition in COVID-19 patients and in control using a competing risk analysis. Of note, although we tried to match COVID-19 patients with septic shock patients, we were unable due to the longer stay of COVID-19 patients. Among 72 patients admitted to the COVID-19 ICUs, 33% acquired 31 MDRB during ICU stay. The incidence density of MDRB acquisition was 30/1000 patient days. Antimicrobial therapy and exposure time were associated with higher rate of MDRB acquisition. Among the 72 SAH patients, 21% acquired MDRB, with an incidence density was 18/1000 patient days. The septic patients had more comorbidities and a greater number of previous hospitalizations than the COVID-19 patients. The incidence density of MDRB acquisition was 30/1000 patient days. The association between COVID-19 and MDRB acquisition (compared to control) risk did not reach statistical significance in the multivariable competing risk analysis (sHR 1.71 (CI 95% 0.93–3.21)). Thus, we conclude that, despite strong physical isolation, acquisition rate of MDRB in ICU patients was at least similar during the COVID-19 first wave compared to previous period.

scholarly journals Aetiology and prevalence of mixed-infections and mono-infections in non-gonococcal urethritis in men: a case-control study

2019 ◽  
Vol 96 (4) ◽  
pp. 306-311 ◽  
Author(s):  
Stephen J Jordan ◽  
Evelyn Toh ◽  
James A Williams ◽  
Lora Fortenberry ◽  
Michelle L LaPradd ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Case Control Study ◽  
Ureaplasma Urealyticum ◽  
Clinical Information ◽  
Mycoplasma Genitalium ◽  
Case Control ◽  
Mixed Infections ◽  
Case Control Studies ◽  
Gonococcal Urethritis ◽  
Control Study

ObjectivesChlamydia trachomatis (CT) and Mycoplasma genitalium (MG) cause the majority of non-gonococcal urethritis (NGU). The role of Ureaplasma urealyticum (UU) in NGU is unclear. Prior case–control studies that examined the association of UU and NGU may have been confounded by mixed infections and less stringent criteria for controls. The objective of this case–control study was to determine the prevalence and aetiology of mixed infections in men and assess if UU monoinfection is associated with NGU.MethodsWe identified 155 men with NGU and 103 controls. Behavioural and clinical information was obtained and men were tested for Neisseria gonorrhoeae and CT, MG, UU and Trichomonas vaginalis (TV). Men who were five-pathogen negative were classified as idiopathic urethritis (IU).ResultsTwelve per cent of NGU cases in which a pathogen was identified had mixed infections, mostly UU coinfections with MG or CT; 27% had IU. In monoinfected NGU cases, 34% had CT, 17% had MG, 11% had UU and 2% had TV. In controls, pathogens were rarely identified, except for UU, which was present in 20%. Comparing cases and controls, NGU was associated with CT and MG monoinfections and mixed infections. UU monoinfection was not associated with NGU and was almost twice as prevalent in controls. Men in both the case and control groups who were younger and who reported no prior NGU diagnosis were more likely to have UU (OR 0.97 per year of age, 95% CI 0.94 to 0.998 and OR 6.3, 95% CI 1.4 to 28.5, respectively).ConclusionsMixed infections are common in men with NGU and most of these are UU coinfections with other pathogens that are well-established causes of NGU. UU monoinfections are not associated with NGU and are common in younger men and men who have never previously had NGU. Almost half of NGU cases are idiopathic.

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