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Cross-Sectional Study
Cross-Sectional Study
Cross-sectional study: examines the relationship between an exposure and disease in a defined population at a single point in time by comparing the prevalence of an exposure with the prevalence of a disease
Uses: public health planning, researching etiology
Strengths: fast, inexpensive, for immutable characteristics
Limits: temporal bias, healthy worker effect
Association Between Serum Total Bilirubin and COPD: Results from a Cross-Sectional Study and a Bidirectional Mendelian Randomization Analysis
Association Between Serum Total Bilirubin and COPD: Results from a Cross-Sectional Study and a Bidirectional Mendelian Randomization Analysis
In this paper, Dai et. al. conducted a cross-sectional study to determine if serum total bilirubin (TB), an exposure, is associated with chronic obstructive pulmonary disease (COPD.) Oxidative stress is very involved in COPD, and TB has been hypothesized to antagonize oxidative stress. Thus, the researchers wanted to determine if TB may potentially protect against COPD, especially as past studies have led to mixed results. 3069 participants were analyzed. They found that a higher risk of COPD was associated with low and high concentrations of TB (U-shaped graph as shown below). There was only a small, specific concentration of TB that was associated with lower COPD. Overall, the exposure and disease had a non-linear relationship; thus, this relationship needs to be studied in greater depth. This is significant as it provides evidence against using TB as a concrete biomarker for COPD, so those in clinical care will not apply less statistically strong data to their patient’s care.
Ecological Study
Ecological Study
Ecological study: examines the relationship between exposure and disease using population-level data rater than individidual-level data
Strengths: inexpensive, includes a wide range of data, fast, good for initial research
Limitations: ecological fallacy, difficult to assess confounding and more complex interactions
An ecological study on the association between characteristics of hospital units and the risk of occupational injuries and adverse events on the example of an Italian teaching hospital
An ecological study on the association between characteristics of hospital units and the risk of occupational injuries and adverse events on the example of an Italian teaching hospital
In this study, Valent et. al. examined how characteristics of different units within a teach hospital were associated with injuries and other adverse events. Data was collected on approximately 3800 people at the University Hospital of Udine in Northeastern Italy during the years 2012 and 2013. The Clinical Risk Unit provided data about the amount of occupational injuries, patient falls, medical errors, and other adverse events. The Occupational Health Office provided data about the unit characteristics, which included data on the sex of the employees, the number of sick-leave days, and more. After performing statistical analyses, they found that the distribution of sex among the employees, the amount of sick-leave and overtime hours, the quantity of examinations, and the quality of being a surgical unit all had associations with at least one of the outcomes measured. These results can help improve the workplace environment and thus improve patient care in hospitals.
Question: What are the benefits of choosing an ecological study design with this particular research question?
Randomized Controlled Trial
Randomized Controlled Trial
Randomized controlled trial: examines the role of an agent in the prevention/treatment of a disease through the active manipulation of a variable
Strengths: high validity
Limitations: noncompliance, expensive, ethical and feasibility issues, reluctance
Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis
Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis
In this randomized clinical trial, Bennell et. al. determined whether or not platelet-rich plasma (PRP) would improve the disease progression of knee osteoarthritis (OA) compared to placebo saline injection. PRP as a potential treatment for OA has been increasing in use, but there’s a lack of rigorous evidence supporting its efficacy. This triple-blinded study included 288 participants, all of whom have medial knee OA and reside in Sydney and Melbourne, Australia. A follow-up was conducted 12 months later. Half of the participants received 3 intra-articular injections every week of PRP, while the other half received a saline placebo. The primary outcomes measured were self-reported knee pain scores as well as MRI-observed changes in medial tibial cartilage volume. The researchers found that there was no significant difference in pain score or joint structure between the two groups, thus supporting for the lack of use of PRP for knee OA. To the left is a graph depicting the lack of significant change in pain scores of the two groups over 2 and 12 months.
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8611484/
Cohort Study
Cohort Study
Cohort study: subjects are defined by exposure level and then followed for disease occurrence in order to examine multiple effects of an exposure
Retrospective cohort study: data in retrieved from the past --> quicker, but suffers from temporal bias
Prospective cohort study: participants followed into the future --> gives more information, but high cost and time
Strengths: good if little is known about the exposure or the exposure is rare
Sodium-Glucose Cotransporter-2 Inhibitors and Urinary Tract Infections: A Propensity Score–matched Population-based Cohort Study
Sodium-Glucose Cotransporter-2 Inhibitors and Urinary Tract Infections: A Propensity Score–matched Population-based Cohort Study
In this study, Alkabbani et. al. conducted a cohort study investigating whether the consumption of sodium-glucose transporter-2 (SGLT2) inhibitors was associated with contracting urinary tract infections (UTIs). The exposure, use of SGLT2 inhibitors, was compared to cohorts who used other comparators dipeptidylpeptidase-4 inhibitors, sulfonylureas, glucagon-like peptide-1 receptor agonists, thiazolidinediones, and insulin. The outcome of interest, UTIs, were determined based on hospitalizations or physician visits. Data was collected from the United Kingdom’s Clinical Practice Research Datalink as well as health-care data stemming from Alberta, Canada. The researchers found that SGLT2 inhibitor use did not significantly increase UTI contraction compared to all other comparators besides insulin. Thus, the researchers concluded that there were no associations between SGLT2 inhibitor use and UTI risk.
Source: https://www.sciencedirect.com/science/article/pii/S149926712100472X
Question: What is the benefit of the comparison group being those who used similar treatments?
Case-Control Study
Case-Control Study
Case-control study: subjects are defined by disease status and exposure histories are compared in order to examine multiple exposures related to a disease
Strengths: good if little is known about a disease, less time and money, rare disease, long latent period
Limitations: recall bias
Risk of drug-induced interstitial lung disease in hospitalised patients: a nested case–control study
Risk of drug-induced interstitial lung disease in hospitalised patients: a nested case–control study
In this study, Jo et. al. conducted a nested case-control study regarding which types of drugs are associated with increased risk of drug-induced interstitial disease (DILD) ion hospitalized patients. Studies done regarding DILD in the past have been difficult to conduct, as the disease is rare. The researchers matched 1541 patients who developed DILD with 5677 control patients without DILD in a one-to-four ratio. Patients were identified using the Diagnosis Procedure Combination Database in Japan. After identifying seventy-five categories of drugs, the researchers picked forty-two drugs that had been potentially associated with DILD in previous research articles. Epidermal growth factor receptor inhibitors were found to be greatly associated with increased DILD with an odds ratio of 16.84. The other five drug categories found to be associated with increased DILD were class III anti arrhythmic drugs, quinolones, anticoagulants, and sulfamethoxazole/trimethoprim, with odds ratios of 7.01, 3.10, 2.58, and 2.54, respectively. Statins were found to be associated with decreased risk of DILD with an odds ratio of 0.68.
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