Indian J Sex Transm Dis AIDS. 2009 Jul-Dec; 30(2): 112–119. Rahul Mhaskar,1,3
Patricia Emmanuel,3,5 Shobha Mishra,4
Sangita Patel,4 Eknath Naik,5 and Ambuj
Kumar1,2,3,5 Whenever a trial is conducted, there are three possible explanations for the results: a) findings are correct (truth), b) represents random variation (chance) or c) they are influenced by systematic error (bias). Random error is deviation from the ‘truth’ and happens due to play of chance (e.g. trials with small sample, etc.).
Systematic distortion of the estimated intervention effect away from the ‘truth’ can also be caused by inadequacies in the design, conduct or analysis of a trial. Several studies have shown that bias can obscure up to 60% of the real effect of a healthcare intervention. A mounting body of empirical evidence shows that ‘biased results from poorly designed and reported trials can mislead decision making in healthcare at all levels’. Poorly conducted and reported RCTs seriously compromise the
integrity of the research process especially when biased results receive false credibility. Therefore, critical appraisal of the quality of clinical research is central to informed decision-making in healthcare. Critical appraisal is the process of carefully and systematically examining research evidence to judge its trustworthiness, its value and relevance in a particular context. It allows clinicians to use research evidence reliably and efficiently. Critical appraisal is intended to enhance
the healthcare professional's skill to determine whether the research evidence is true (free of bias) and relevant to their patients. Keywords: Critical appraisal, randomized controlled trials, decision-making A five-year-old male child presents with dry and scaly skin on his cheeks and was brought to the pediatric out-patient clinic by his parents. After initial evaluation, the young
patient was diagnosed with atopic dermatitis. During the initial consultation, a junior resident mentions that a topical formulation of tacrolimus, an immunosuppressant currently marketed for the prevention of rejection after solid organ transplant, is a potential therapeutic agent for atopic dermatitis. Nevertheless, the senior resident wants to know the evidence related to the safety and efficacy of topical tacrolimus in treating younger patients with atopic dermatitis. The junior resident
enthusiastically performs an electronic search of the literature and finds a randomized controlled trial (RCT) conducted to determine the safety and efficacy of tacrolimus ointment in pediatric patients with moderate-to-severe atopic dermatitis.[1] The junior resident also mentions that since this is an RCT, it should be considered reliable as it stands at a higher level in
the hierarchy of the evidence pyramid [Figure 1]. However, the question now arises that because the trial claims to be a RCT, are the results from this study reliable, and whether the results are applicable to the young patient in question here? Evidence pyramid showing the hierarchy of evidence.[13] THE NEED FOR CRITICAL APPRAISALWhenever a trial is conducted, there are three possible explanations for the results: a) findings are correct (truth), b) represents random variation (chance) or c) they are influenced by systematic error (bias). Random error is deviation from the ‘truth’ and happens due to play of chance (e.g. trials with small sample, etc.). Systematic distortion of the estimated intervention effect away from the ‘truth’ can also be caused by inadequacies in the design, conduct or analysis of a trial. Several studies have shown that bias can obscure up to 60% of the real effect of a healthcare intervention. A mounting body of empirical evidence shows that ‘biased results from poorly designed and reported trials can mislead decision-making in healthcare at all levels’.[2] Poorly conducted and reported RCTs seriously compromise the integrity of the research process especially when biased results receive false credibility. Therefore, critical appraisal of the quality of clinical research is central to informed decision-making in healthcare. Critical appraisal is the process of systematically examining research evidence to judge its trustworthiness, its value and relevance in a particular context. It allows clinicians to use research evidence reliably and efficiently.[3] Critical appraisal is intended to enhance the healthcare professional's skill to determine whether the research evidence is true (free of bias) and relevant to their patients. In this paper, we focus on the evaluation of an article (RCT) on a treatment intervention. The same framework would be applicable to preventive interventions as well. Three essential questions need to be asked when dealing with an article on therapeutic intervention.[4]
Absolute Risk Reduction (ARR) = risk of the outcome in the control group – risk of the outcome in the treatment group. In our example, the ARR = 0.25 – 0.20 = 0.05 or 5%. Absolute Risk Reduction (ARR) indicates the decrease in risk of a given outcome in patients with the treatment in relation to risk of that outcome in individuals not receiving the treatment. An ARR of ‘0’ suggests that there is no difference between the two groups indicating that treatment had no effect. Relative Risk Reduction (RRR) = absolute risk reduction / risk of the outcome in the control group. In our example, the RRR = 0.05/0.25 = 0.20 or 20%. Relative Risk Reduction (RRR) indicates the reduction in the rate of the outcome in the treatment group relative to that in the control group. Number Needed to Treat (NNT) = 1 / ARR. In our example, the NNT = 1/ 0.05 = 20. Number Needed to Treat (NNT) is the number of patients needs to be treated in order to prevent one additional bad outcome. In conclusion, the reporting of RCT can be plagued with numerous quality control issues. Consolidated Standards of Reporting Trials group (CONSORT) has developed various initiatives to improve the issues arising from inadequate reporting of RCTs. The main products of CONSORT are the CONSORT statement[11] and CONSORT harms statement,[12] which are an evidence-based, minimum set of recommendations for reporting RCTs. These offer a standard way for authors to prepare reports of trial findings, facilitating their complete and transparent reporting and aiding their critical interpretation.[11] In essence there is a need to assess the quality of evidence; and, if adequate, establish the range of true treatment effect. Then, consider whether results are generalizable to the patient at hand, and whether the measured outcomes are relevant and important. Finally, carefully review the patient's risk of TRH and related treatment benefit – risk ratio.[6] We believe that methodologically assessing the strength of evidence and using it to guide treatment of each patient will certainly improve health outcomes. Additional materialA critical appraisal worksheet (with permission from http://www.cebm.net/index.aspx?o=1157) is provided in the appendix section of the manuscript. We encourage the readers to assess the manuscript mentioned in the clinical scenario[1] and critically appraise it using the worksheet (see appendix). ACKNOWLEDGEMENTThis paper was supported in part by the Fogarty International Center/USNIH: Grant # 1D43TW006793-01A2-AITRP. FootnotesSource of Support: Fogarty International Center/USNIH: Grant #1D43TW006793-01A2-AITRP. Conflict of Interest: None declared. REFERENCES1. Boguniewicz M, Fiedler VC, Raimer S, Lawrence ID, Leung DY, Hanifin JM. A randomized, vehicle-controlled trial of tacrolimus ointment for treatment of atopic dermatitis in children. J Allergy Clin Immunol. 1998;102:637–44. [PubMed] [Google Scholar] 2. Moher D, Schulz KF, Altman D. CONSORT Group. The CONSORT Statement: Revised recommendations for improving the quality of reports of parallel-group randomized trials 2001. Explore (NY) 2005;1:40–5. [PubMed] [Google Scholar] 3. Burls A. What is critical appraisal? 2009 [Google Scholar] 4. Guyatt GH, Sackett DL, Cook DJ. Users’ guides to the medical literature.II. How to use an article about therapy or prevention. A. Are the results of the study valid? Evidence-Based Medicine Working Group. JAMA. 1993;270:2598–601. [PubMed] [Google Scholar] 5. Jüni P, Altman DG, Egger M. Systematic reviews in health care: Assessing the quality of controlled clinical trials. BMJ. 2001;323:42–6. [PMC free article] [PubMed] [Google Scholar] 6. Guyatt GH, Sackett DL, Cook DJ. Users’ guides to the medical literature. II. How to use an article about therapy or prevention. B. What were the results and will they help me in caring for my patients? Evidence-Based Medicine Working Group. JAMA. 1994;271:59–63. [PubMed] [Google Scholar] 7. Clinical trials, Shapiro SH. New York: Marcel Dekker; 1983. Armitage. Exclusions, losses to follow-up and withdrawals in clinical trials. [Google Scholar] 8. Gail MH. Eligibility exclusions, losses to follow-up, removal of randomized patients, and uncounted events in cancer clinical trials. Cancer Treat Rep. 1985;69:1107–13. [PubMed] [Google Scholar] 9. Rothwell PM. Treating individuals 2.Subgroup analysis in randomised controlled trials: importance, indications, and interpretation. Lancet. 2005;365:176–86. [PubMed] [Google Scholar] 10. Oxford, T.U.o. Critical appraisal sheet for RCT. 2009 [Google Scholar] 11. Egger M, Altman DG, Schulz KG. The CONSORT Statement: Explanation and Elaboration. Ann Intern Med. 2002;136:926–7. [PubMed] [Google Scholar] 12. Ioannidis JP, Evans SJ, Gøtzsche PC, O’Neill RT, Altman DG, Schulz K, et al. Better reporting of harms in randomized trials: an extension of the CONSORT statement. Ann Intern Med. 2004;141:781–8. [PubMed] [Google Scholar] 13. Sackett DL. New York: Churchill Livingstone Inc; 2000. Evidence-based medicine.How to practice and teach EBM; p. 136. [Google Scholar] Articles from Indian Journal of Sexually Transmitted Diseases and AIDS are provided here courtesy of Wolters Kluwer -- Medknow Publications What is the impact of a poorly designed database?Poor Design/Planning
Consequences of lack of planning are seen further down the line and impacts projects in terms of time management. Improper planning of the database leaves you with no time to go back and fix errors and leads to malicious cyber attacks.
What are some common problems with poorly designed databases Check all that apply?So, the list:. Poor design/planning.. Ignoring normalization.. Poor naming standards.. Lack of documentation.. One table to hold all domain values.. Using identity/guid columns as your only key.. Not using SQL facilities to protect data integrity.. Not using stored procedures to access data.. What are two potential consequences that can result from a poorly designed database?A badly designed database has the following problems: Related data is scattered over various tables. A change must be updated at many places. It's possible that the information is only half present, it's there in one table, but missing in another one.
Why is database design so important?Importance of Database Design
To ensure data accuracy, you must design a database that only stores relevant and valuable information. A well-designed database is essential to guarantee information consistency, eliminate redundant data, efficiently execute queries, and improve the database's performance.
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