Characteristics and Reporting of Number Needed to Treat, Number Needed to Harm, and Absolute Risk Reduction in Controlled Clinical Trials, 2001-2019

Abstract Objective This systematic review aimed to establish the evidence behind the use of pre-operative calcium, vitamin D or both calcium and vitamin D to prevent post-operative hypocalcaemia in patients undergoing thyroidectomy. Method This review included prospective clinical trials on adult human patients that were published in English and which studied the effects of pre-operative supplementation with calcium, vitamin D or both calcium and vitamin D on the rate of post-operative hypocalcaemia following total thyroidectomy. Results Seven out of the nine trials included reported statistically significantly reduced rates of post-operative laboratory hypocalcaemia (absolute risk reduction, 13–59 per cent) and symptomatic hypocalcaemia (absolute reduction, 11–40 per cent) following pre-operative supplementation. Conclusion Pre-operative treatment with calcium, vitamin D or both calcium and vitamin D reduces the risk of post-operative hypocalcaemia and should be considered in patients undergoing total thyroidectomy.

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Folic Acid and Folinic Acid for Reducing Side Effects in Patients Receiving Methotrexate for Rheumatoid Arthritis

The Journal of Rheumatology ◽

10.3899/jrheum.130738 ◽

2014 ◽

Vol 41 (6) ◽

pp. 1049-1060 ◽

Cited By ~ 60

Author(s):

Beverley Shea ◽

Michael V. Swinden ◽

Elizabeth Tanjong Ghogomu ◽

Zulma Ortiz ◽

Wanruchada Katchamart ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Clinical Trials ◽

Folic Acid ◽

Side Effects ◽

Folinic Acid ◽

Risk Reduction ◽

Absolute Risk ◽

Absolute Risk Reduction ◽

Risk Of Bias ◽

Serum Transaminase

Objective.To perform a systematic review of the benefits and harms of folic acid and folinic acid in reducing the mucosal, gastrointestinal, hepatic, and hematologic side effects of methotrexate (MTX); and to assess whether folic or folinic acid supplementation has any effect on MTX benefit.Methods.We searched the Cochrane Library, MEDLINE, EMBASE, and US National Institutes of Health clinical trials registry from inception to March 2012. We selected all double-blind, randomized, placebo-controlled clinical trials in which adult patients with rheumatoid arthritis (RA) were treated with MTX (dose ≤ 25 mg/week) concurrently with folate supplementation. We included only trials using low-dose folic or folinic acid (a starting dose of ≤ 7 mg weekly) because the high dose is no longer recommended or used. Data were extracted from the trials, and the trials were independently assessed for risk of bias using a predetermined set of criteria.Results.Six trials with 624 patients were eligible for inclusion. Most studies had low or unclear risk of bias for key domains. The quality of the evidence was rated as “moderate” for each outcome as assessed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) working group, with the exception of hematologic side effects, which were rated as “low.” There was no significant heterogeneity between trials, including where folic acid and folinic acid studies were pooled. For patients supplemented with any form of exogenous folate (either folic or folinic acid) while receiving MTX therapy for RA, a 26% relative (9% absolute) risk reduction was seen for the incidence of gastrointestinal side effects such as nausea, vomiting, or abdominal pain (RR 0.74, 95% CI 0.59 to 0.92; p = 0.008). Folic and folinic acid also appear to be protective against abnormal serum transaminase elevation caused by MTX, with a 76.9% relative (16% absolute) risk reduction (RR 0.23, 95% CI 0.15 to 0.34; p < 0.00001), as well as reducing patient withdrawal from MTX for any reason [60.8% relative (15.2% absolute) risk reduction, RR 0.39, 95% CI 0.28 to 0.53; p < 0.00001].Conclusion.The results support a protective effect of supplementation with either folic or folinic acid for patients with RA during treatment with MTX. There was a clinically important significant reduction shown in the incidence of GI side effects and hepatic dysfunction (as measured by elevated serum transaminase levels), as well as a clinically important significant reduction in discontinuation of MTX treatment for any reason.

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MEASURING THE SIZE OF A TREATMENT EFFECT: RELATIVE RISK REDUCTION, ABSOLUTE RISK REDUCTION, AND NUMBER NEEDED TO TREAT

Evidence-Based Ophthalmology ◽

10.1097/01.ieb.0000389901.44113.62 ◽

2010 ◽

Vol 11 (4) ◽

pp. 190-194

Author(s):

Hussein Hollands ◽

Peter J. Kertes

Keyword(s):

Relative Risk ◽

Risk Reduction ◽

Treatment Effect ◽

Relative Risk Reduction ◽

Absolute Risk ◽

Absolute Risk Reduction ◽

Number Needed To Treat

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Abstract 02: Distribution Of Predicted Cardiovascular And All-cause Mortality Benefit Of Intensive Vs Standard Blood Pressure Control Among Us Adults Eligible For The Systolic Blood Pressure Intervention Trial

Hypertension ◽

10.1161/hyp.78.suppl_1.02 ◽

2021 ◽

Vol 78 (Suppl_1) ◽

Author(s):

Catherine G Derington ◽

Brandon Bellows ◽

Gabriel S Tajeu ◽

Jennifer S Herrick ◽

Ransmond O Berchie ◽

...

Keyword(s):

Blood Pressure ◽

Risk Reduction ◽

Racial Differences ◽

Absolute Risk ◽

Absolute Risk Reduction ◽

Pressure Control ◽

Number Needed To Treat ◽

Health And Nutrition ◽

Population Sizes ◽

Event Rates

Introduction: If resources are scarce, achieving national SBP control goals will require prioritizing treatment among those likely to benefit. To identify patients with greatest predicted benefit with intensive SBP treatment and estimate population sizes, we applied algorithms to community samples who met the SPRINT enrollment criteria. Methods: The published algorithms separately predict the absolute risk reduction in CVD events and mortality at 3.26 years with intensive (<120 mm Hg) vs standard (<140 mm Hg) SBP lowering. We applied and calibrated the algorithms to SPRINT standard arm participants (n=4 399) and samples meeting SPRINT enrollment criteria from the National Health and Nutrition Examination Survey (NHANES, n=1 297) and the Reasons for Geographic And Racial Differences in Stroke (REGARDS, n=2 785). Predicted absolute risk reduction estimated number needed to treat (NNT), categorized as <50, 50-100, and ≥100. Observed 3.26 year CVD event (SPRINT, REGARDS) and mortality rates (all cohorts) were calculated. Results: The median ages were 67 (SPRINT), 69 (NHANES), and 72 (REGARDS). Greater proportions of NHANES and REGARDS vs SPRINT had predicted NNT <100 for CVD events (NHANES 94.8%, REGARDS 99.2%, SPRINT 87.8%) and mortality (NHANES 64.3%, REGARDS 63.7%, SPRINT 38.8%) ( Table ). Event rates were comparable within NNT groups. Conclusions: Predicted NNT distributions differ between cohorts but event rates are similar. Most adults who meet SPRINT enrollment criteria have predicted NNT <100 for CVD and mortality with intensive SBP treatment. These results suggest that published algorithms can identify those most likely to benefit and can guide implementation.

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Nonvitamin-K-antagonist oral anticoagulants versus warfarin in patients with atrial fibrillation and previous stroke or transient ischemic attack: An updated systematic review and meta-analysis of randomized controlled trials

International Journal of Stroke ◽

10.1177/1747493017700663 ◽

2017 ◽

Vol 12 (6) ◽

pp. 589-596 ◽

Cited By ~ 43

Author(s):

George Ntaios ◽

Vasileios Papavasileiou ◽

Hans-Chris Diener ◽

Konstantinos Makaritsis ◽

Patrik Michel

Keyword(s):

Atrial Fibrillation ◽

Relative Risk ◽

Risk Reduction ◽

Relative Risk Reduction ◽

Absolute Risk ◽

Meta Analysis ◽

Oral Anticoagulants ◽

Absolute Risk Reduction ◽

Number Needed To Treat ◽

Ischemic Attack

Background In a previous systematic review and meta-analysis, we assessed the efficacy and safety of nonvitamin-K antagonist oral anticoagulants versus warfarin in patients with atrial fibrillation and stroke or transient ischemic attack. Since then, new information became available. Aim The aim of the present work was to update the results of the previous systematic review and meta-analysis. Methods We searched PubMed until 24 August 2016 for randomized controlled trials using the following search items: “atrial fibrillation” and “anticoagulation” and “warfarin” and “previous stroke or transient ischemic attack.” Eligible studies had to be phase III trials in patients with atrial fibrillation comparing warfarin with nonvitamin-K antagonist oral anticoagulants currently on the market or with the intention to be brought to the market in North America or Europe. The outcomes assessed in the efficacy analysis included stroke or systemic embolism, stroke, ischemic or unknown stroke, disabling or fatal stroke, hemorrhagic stroke, cardiovascular death, death from any cause, and myocardial infarction. The outcomes assessed in the safety analysis included major bleeding, intracranial bleeding, and major gastrointestinal bleeding. We performed fixed effects analyses on intention-to-treat basis. Results Among 183 potentially eligible articles, four were included in the meta-analysis. In 20,500 patients, compared to warfarin, nonvitamin-K antagonist oral anticoagulants were associated with a significant reduction of stroke/systemic embolism (relative risk reduction: 13.7%, absolute risk reduction: 0.78%, number needed to treat to prevent one event: 127), hemorrhagic stroke (relative risk reduction: 50.0%, absolute risk reduction: 0.63%, number needed to treat: 157), any stroke (relative risk reduction: 13.1%, absolute risk reduction: 0.7%, number needed to treat: 142), and intracranial hemorrhage (relative risk reduction: 46.1%, absolute risk reduction: 0.88%, number needed to treat: 113) over 1.8–2.8 years. Conclusions This updated meta-analysis in 20,500 atrial fibrillation patients with previous stroke or transient ischemic attack shows that compared to warfarin non-vitamin-K antagonist oral anticoagulants are associated with a significant reduction of stroke, stroke or systemic embolism, hemorrhagic stroke, and intracranial bleeding.

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Adjuvant Chemotherapy for Breast Cancer: How Presentation of Recurrence Risk Influences Decision-Making

Journal of Clinical Oncology ◽

10.1200/jco.2003.06.025 ◽

2003 ◽

Vol 21 (23) ◽

pp. 4299-4305 ◽

Cited By ~ 61

Author(s):

Celia Chao ◽

Jamie L. Studts ◽

Troy Abell ◽

Terence Hadley ◽

Lynne Roetzer ◽

...

Keyword(s):

Breast Cancer ◽

Relative Risk ◽

Risk Reduction ◽

Survival Benefit ◽

Relative Risk Reduction ◽

Absolute Risk ◽

Treatment Decision ◽

Absolute Risk Reduction ◽

Number Needed To Treat ◽

The Impact

Purpose: The purpose of this study was to examine the impact of four methods of communicating survival benefits on chemotherapy decisions. We hypothesized that the four methods of communicating mathematically equivalent risk information would lead to different chemotherapy decisions. Methods: Each participant received two hypothetical scenarios regarding their mother (a postmenopausal woman with an invasive, lymph node-negative, hormone receptor-positive breast cancer) and was asked to decide whether they would encourage their mother to take chemotherapy in addition to surgery and tamoxifen. In the part 1, participants received one of four methods of describing the chemotherapy survival benefit: (1) relative risk reduction, (2) absolute risk reduction, (3) absolute survival benefit, or (4) number needed to treat. In part 2, each participant received all four methods. Following each decision, participants were asked to rate their confidence and confusion regarding their decision. Results: Participants included 203 preclinical medical students. In part 1, participants who received relative risk reduction information were significantly more likely to endorse chemotherapy. In part 2, there were no treatment decision differences when participants received all four methods of communicating survival benefits of chemotherapy. However, receiving all four methods led to significantly higher ratings of confusion. In deciding on endorsing chemotherapy, participants understood the information best when presented with data in the absolute survival benefit format. Conclusion: These results support the hypothesis that the method used to present information about chemotherapy influences treatment decisions. Absolute survival benefit is the most easily understood method of conveying the information regarding benefit of treatment.

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Outcome Reporting Bias in COVID-19 mRNA Vaccine Clinical Trials

Medicina ◽

10.3390/medicina57030199 ◽

2021 ◽

Vol 57 (3) ◽

pp. 199

Author(s):

Ronald B. Brown

Keyword(s):

Clinical Trials ◽

Relative Risk ◽

Risk Reduction ◽

Relative Risk Reduction ◽

Absolute Risk ◽

Absolute Risk Reduction ◽

Reporting Bias ◽

Outcome Reporting Bias ◽

Outcome Reporting ◽

Risk Reduction Measures

Relative risk reduction and absolute risk reduction measures in the evaluation of clinical trial data are poorly understood by health professionals and the public. The absence of reported absolute risk reduction in COVID-19 vaccine clinical trials can lead to outcome reporting bias that affects the interpretation of vaccine efficacy. The present article uses clinical epidemiologic tools to critically appraise reports of efficacy in Pfzier/BioNTech and Moderna COVID-19 mRNA vaccine clinical trials. Based on data reported by the manufacturer for Pfzier/BioNTech vaccine BNT162b2, this critical appraisal shows: relative risk reduction, 95.1%; 95% CI, 90.0% to 97.6%; p = 0.016; absolute risk reduction, 0.7%; 95% CI, 0.59% to 0.83%; p < 0.000. For the Moderna vaccine mRNA-1273, the appraisal shows: relative risk reduction, 94.1%; 95% CI, 89.1% to 96.8%; p = 0.004; absolute risk reduction, 1.1%; 95% CI, 0.97% to 1.32%; p < 0.000. Unreported absolute risk reduction measures of 0.7% and 1.1% for the Pfzier/BioNTech and Moderna vaccines, respectively, are very much lower than the reported relative risk reduction measures. Reporting absolute risk reduction measures is essential to prevent outcome reporting bias in evaluation of COVID-19 vaccine efficacy.

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