23
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Design and data analysis case-controlled study in clinical research

      other

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Clinicians during their training period and practice are often called upon to conduct studies to explore the association between certain exposures and disease states or interventions and outcomes. More often they need to interpret the results of research data published in the medical literature. Case-control studies are one of the most frequently used study designs for these purposes. This paper explains basic features of case control studies, rationality behind applying case control design with appropriate examples and limitations of this design. Analysis of sensitivity and specificity along with template to calculate various ratios are explained with user friendly tables and calculations in this article. The interpretation of some of the laboratory results requires sound knowledge of the various risk ratios and positive or negative predictive values for correct identification for unbiased analysis. A major advantage of case-control study is that they are small and retrospective and so they are economical than cohort studies and randomized controlled trials.

          Related collections

          Most cited references6

          • Record: found
          • Abstract: not found
          • Article: not found

          Diagnostic tests. 1: Sensitivity and specificity.

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Nonsteroidal anti-inflammatory drugs may protect against Parkinson disease.

            Markers of neuroinflammation, including activated microglia and increased levels of circulating proinflammatory cytokines, have been observed in the brains and CSF of patients with Parkinson disease (PD). Yet the link between anti-inflammatory agents and PD in humans remains uncertain, despite indications that neuroinflammation may contribute to cell death in the PD brain and experimental evidence of anti-inflammatory agents such as nonsteroidal anti-inflammatory drugs (NSAIDs) exerting neuroprotective effects in animal models. Using a population-based approach, we studied NSAID use among 293 incident idiopathic PD cases and 286 age-, race-, and gender-matched controls from three rural California counties. Our data suggested a decreased risk of PD among regular (>or=2 pills/week for at least 1 month) aspirin NSAID users (OR, 0.80; 95% CI, 0.56 to 1.15). A stronger protective effect was observed for regular nonaspirin NSAID users (OR, 0.52; 95% CI, 0.35 to 0.79), particularly those who reported 2 or more years of use (OR, 0.44; 95% CI, 0.26 to 0.74). The aspirin effect estimates differed by gender, showing a protective effect only in women, especially among long term (>or=24 months) regular users (OR, 0.51; 95% CI, 0.26 to 1.02). Our study contributes to the growing body of literature suggesting a protective role for nonsteroidal anti-inflammatory drugs (NSAIDs) in Parkinson disease (PD). Given our results and the biologic plausibility of a neuroprotective function for NSAIDs there is a pressing need for further studies elucidating the protective role such drugs may play in PD.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Amphetamine exposure is elevated in Parkinson's disease.

              Since the 1930's, amphetamine drugs have been used therapeutically and recreationally. High doses are associated with acute injury to axon terminals of dopaminergic neurons. It is unknown whether low dose exposure to amphetamine over a prolonged time period is associated with the development of Parkinson's disease (PD). A telephone survey of drug and chemical exposure was administered to patients from three faculty practice clinics at UCSF. Patients were asked to participate if they had been diagnosed with peripheral neuropathy (PN), amyotrophic lateral sclerosis (ALS), or PD between the ages of 40 and 64. Spouses or caregivers were also asked to participate. "Amphetamine exposure" was defined as a prior use of amphetamine, methamphetamine or dextroamphetamine. "Prolonged exposure" was defined as amphetamine use that occurred more than twice a week for > or =3 months or weekly usage for > or =1 year and had to occur before diagnosis of the neurological condition. Prolonged exposure to either prescribed or non-prescribed amphetamine was common, occurring in 15% with PN (11/76), 13% with ALS (9/72), and 11% with PD (17/158). Prolonged amphetamine exposure was more frequent in diseased patients compared to spouses when all diseases were combined (adjusted OR=3.15, 95% CI 1.42-7.00, p=0.005). When tested alone, only the Parkinson's disease group retained statistical significance (adjusted OR=8.04, 95% CI 1.56-41.4, p=0.013). For most individuals, exposure occurred long before diagnosis (averages: PN 25 years, ALS 28 years, and PD 27 years). The elevated rate of prolonged amphetamine exposure in PD is intriguing and bears further investigation.
                Bookmark

                Author and article information

                Journal
                Ann Indian Acad Neurol
                Ann Indian Acad Neurol
                AIAN
                Annals of Indian Academy of Neurology
                Medknow Publications & Media Pvt Ltd (India )
                0972-2327
                1998-3549
                Oct-Dec 2013
                : 16
                : 4
                : 483-487
                Affiliations
                [1]Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
                [1 ]Department of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Louiseville, USA
                [2 ]Department of Justice Administration, University of Louisville, Louiseville, USA
                Author notes
                For correspondence: Dr. Sanjeev V. Thomas, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum - 695 011, Kerala, India. E-mail: sanjeev.v.thomas@ 123456gmail.com
                Article
                AIAN-16-483
                10.4103/0972-2327.120429
                3841585
                e7321b86-7037-478c-8976-a4e2a7d144b3
                Copyright: © Annals of Indian Academy of Neurology

                This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 01 March 2013
                : 03 July 2013
                : 03 August 2013
                Categories
                Statistically Speaking

                Neurology
                case-control study,analysis,design
                Neurology
                case-control study, analysis, design

                Comments

                Comment on this article